CA1211698A - Pulse combustor - Google Patents
Pulse combustorInfo
- Publication number
- CA1211698A CA1211698A CA000422260A CA422260A CA1211698A CA 1211698 A CA1211698 A CA 1211698A CA 000422260 A CA000422260 A CA 000422260A CA 422260 A CA422260 A CA 422260A CA 1211698 A CA1211698 A CA 1211698A
- Authority
- CA
- Canada
- Prior art keywords
- combustion chamber
- chamber
- extending portion
- end plate
- pulse combustor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C15/00—Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
Abstract
Abstract of the Disclosure A pulse combustor has a housing having a combustion chamber. The housing has a cylindrical body, a first end plate closing one end of the body, and a second end plate closing the other end of the body. Air inlet holes and fuel gas inlet holes are formed in the second end plate and communicate with the chamber. Air and a fuel gas are fed into the chamber through the holes, and a mixture gas of the air and the fuel gas flows along the axial direction of the body. The mixture gas is ignited by a plug arranged in the chamber, and a flame propagates along the axial direction of the body.
A tail pipe is mounted on the body in communication with the chamber. The tail pipe has an extending portion extending from the chamber along a direction perpen-dicular to the axial direction of the body. Combustion gas produced in the chamber is exhausted into the extending portion.
A tail pipe is mounted on the body in communication with the chamber. The tail pipe has an extending portion extending from the chamber along a direction perpen-dicular to the axial direction of the body. Combustion gas produced in the chamber is exhausted into the extending portion.
Description
lZ1~6~3 The present invention relates to a pulse combus-tor~
A pulse combustor is widely known as a type of combustor whiCh has a high combustion efficiency. The pulse combustor is commonly used as a heating source S for deviceSsuch as a hot water supplying apparatus.
A pulse combustor has a housing including a combustion chamber, and a long, slerlder tube, Which iS called a "tail pipe", communicating with the chamber mounted in the housing. Combustion gas produced in the chamber is exhausted while pulsating in the tail pipe. The housing ~6S~c ~ L~/
has an air inlet hole and a fuel gas inlet hole~communi-cating with the chamber. Air and fuel gas are auto-matically fed into the chamber through the air inlet hole and the fuel gas inlet hole due to a negative pressure produced in the chamber, respectively. A flame produced at the time of combustion is propagated along a predetermined direction in the chamber. The predeter-mined direction is called the "propagating direction of a flame".
In a conventional pulse combustor, a tail pipe extends from the housing alona the above-described propagating direction of the flame. This is because the conventional pulse combustor has been thvught to fail to generate a pulse if the tail pipe does not extend in the propagating direction of the flame.
However, in the combustor of this type it is difficult to sufficiently mix the air and the fuel gas and to
A pulse combustor is widely known as a type of combustor whiCh has a high combustion efficiency. The pulse combustor is commonly used as a heating source S for deviceSsuch as a hot water supplying apparatus.
A pulse combustor has a housing including a combustion chamber, and a long, slerlder tube, Which iS called a "tail pipe", communicating with the chamber mounted in the housing. Combustion gas produced in the chamber is exhausted while pulsating in the tail pipe. The housing ~6S~c ~ L~/
has an air inlet hole and a fuel gas inlet hole~communi-cating with the chamber. Air and fuel gas are auto-matically fed into the chamber through the air inlet hole and the fuel gas inlet hole due to a negative pressure produced in the chamber, respectively. A flame produced at the time of combustion is propagated along a predetermined direction in the chamber. The predeter-mined direction is called the "propagating direction of a flame".
In a conventional pulse combustor, a tail pipe extends from the housing alona the above-described propagating direction of the flame. This is because the conventional pulse combustor has been thvught to fail to generate a pulse if the tail pipe does not extend in the propagating direction of the flame.
However, in the combustor of this type it is difficult to sufficiently mix the air and the fuel gas and to
2~
~ 2 -completely burn the resulting mixture. As a resulk, the exhaust level o~ ~arbon monoxide (CO) gas in this combus-tor is significant, so that approx. 0.01 to 0.1% of the exhaust gas is Co.
The present invention has for its object the provision of a pulse combustor which is better able properly to mix air and fuel gas and able more completely to burn a mixture of the two.
According to the invention, a pulse combustor comprises a housing, having a cylindrical combustion chamber, for propagating a flame generated in the chamber in a predetermined direction; guiding means for guiding air and a fuel gas into the combustion chamber and for defining a flow path for a mixture gas of the air and the fuel gas in the predetermined direction; igniting means for i~niting the mixture gas to generate the flame with combustion gas in the comhustion chamber; and a tail pipe mounted on the housing in communication with the combustion chamber for guiding combustion gas produced in the combustion chambPr out of the combustion chamber, the tail pipe having a straight extending portion extend-ing non-tangentially from the combustion chamber in a direction perpendicular to said predetermined direction, and the extending portion being formed to satisfy the relationship of the following formula: h ~ 21D wherein h rep-esents the axial length of said straight extending portion, and D represents the diameter of said combustion chamber.
-~ ~z~
The tail pipe thus has an extending portion which extends along a direction substantially perpendicular to the propagating direction of a flame. The flow direction of th~ gas mixture and the reverse flow direction of the combustion gas from the tail pipe to the combustion chamber are thus perpenclicular, with the result that the flow of the gases in the chamber becomes turbulent.
Accordingly, the fuel gals and the air can be better mixed, the gas mixture can be c:ompletely burned, and the pressure produced in the chamber can be raised. In this manner, there is provided a pulse combustor which is capable of providing low exhaust gaLs CO gas content and of providing more complete burning of the gas mixture at high loads.
This invention can be more fully understood from lS the following detailed description when taken in conjunc-tion with the accompanying drawings, in which:
Fig. 1 is a longitudinal sectional view of a hot water supply apparatus having a pulse combustor according to an embodiment of the present invention;
Fig. 2 is a longitudinal sectional view of the pulse combustor;
Figs. 3A and 3B are sectional viewsschematically showing the operating states of the combustor;
Figs. 4A through 4C are schematic views of pulse combustors respectively showing the siæe of the presentpulse combustor and the sizes of two conventional pulse combustors of different types;
Fig. 5 is a longitudinal sectional view of the ~21~L69~3 - 3a ~
combustor schematically showing the disposition of a tail pipe and a co~ustion chamber;
. . .
~Zl~1.6~1~
Figs. 6A through 6D are sectional views sche-matically showing the operating states of pulse combustors having tail pipes provided at different positions;
Fig. 7 is a view showing the variation in the exhaust gas characteristics of co gas with respect to the instaLling positions of the tail pipe; and Fig. 8 is a sectional view schematically showing a modified embodiment of the present invention.
An embodiment of the present invention will no~ be described in more detail with reference to the accom-panying drawings.
Fig. 1 shows a hot water supplying apparatus 12 which has a pulse combustor 10 according to an embodiment of the present invention. The apparatus 12 has a supporting frame 14 and a hot water storage tank 16 of substantially cylindrical shape supported on the frame 14. The -tank 16 has a hot water supplying tube 18 moun~ed at the top end thereofl and at the bottom thereof a water supplying tube 20. The combustor ].0 is arranged in the inner bottom portion of the tank 16.
The combustor 10 comprises a housing 22 fixedly secured to the tank 12, and a tail pipe 24 extending from the housing 22 into the tank ~. The tail pipe 24 operates as a heat exchanger. The extended end of the tail pipe 24 is connected to an exhaust muffler 26 provided in the frame 14.
~2~
As shown in Fig. 2, the housing 22 of the com~ustor 10 comprises a body 28 of cylindrical shape, a first flat end plate 30 secured to the body 28 for blocking the left end of the body and a second flat end plate 32 detachably mounted on the body for blocking the right end of the body and facing the first end plate 30.
The body 28 defines a combustion chamber 34 of cylin-~drical hollow shape with the first and second plates 30 and 32 in the housing 22. The body 28 has a flange~36 at the right end thereof and the second plate 32 has a ~lang~ 38. The flange 38 of the plate 32 is clamped wi~th bol-ks 40 ko the flange 36 of the body 28. The ~lange 36 of the body 28 is fixed with the bolts 40 to the tank 16.
lS A number of air inlet holes 42:and a~number of~
fuel gas inlet holes 44 are formed through the plate 32.
The holes 42 are extended along:the axial direction of -the body 28, and are disposed along the circumferentlal direction coaxial with the body. The holes 44 are extended along the axial direction of the body 28 and are disposed along the circumferential direction coaxlal with the body. The diameter of~the hole 42 is formed larger than that of the~hole;~44.~ The holes~42 are~
disposed inside the holes 44. A throttle:~late 46 ~
confronting the plate 32 is~:provided in the chamber 34.
The plate 46 is formed in a~ circular:shape in such a manner that the peIipheral edge thereof is fixed to the :
~21~6 inner peripheral s~rface of the body 28. The interior of the chamber 34 is partitioned by the plate 46 into a mixture Section 48 commUnicating with ~he holes 44 and 42, and a combustion section 49 communicating with the tail pipe 24. A communication hole So is formed coaxial with t;he body 28, in the plate 46, thereby communicating the sections 48 and 49. In the section 48 an annular flap valve! 52 for opening and closing the hoLes 42 and 44, and an annular valve retainer 54 are arranged. The holes 42 and 44, the valve 52, the retainer 54 and the plate 46 form a part of guiding means in the pulse combustor of the present invention.
An ignition plug 56 is mounted as igniting means at the plate 32. This plug 56 has a holder 58 fixed to the center of the plate 32, and a pair of terminals 60 extendinq from the holder 58 into the chamber 34 along the axial direction of the body 28. The terminals 60 extend into the section 43 through the section 48 and the hole 50.
A cover 62 of cylindrical shape is mounted with the bolts 40 on the outer surface of the plate 32.
This cover 62 is mounted coa~ially with the body 28, and has an inner diameter substantially equal to that of the body 28. An air chamber 64 communicating with the holes 42 is defined by the cover 62 and the plate 32. An air supplying tube 66 is mounted at the cover 62 and communicates with the chamber 640 A gas su~plying - ~2~
tube 68 communicating with the holes 44 is mounted on the oUter surface of the plate 32, and extends exter-nally through the cover 62. The tubes 66 and 68 form a part of the guiding means. In Fig. 2, reference numeral 70 designates lead wires of the plug 56.
As shown in Figs. l a~d 2, the tail pipe 24 is mounted on the! body 28 of the housing 22, and includes an extending portion 72 which communicates with the chamber 34. This extending portion 72 is mounted at the lower end thereof o]n the body 28, and extends upwardly from the body 28 perpendicular to the axial direction of the body 28. The tail pipe 24 has a descending portion 74. The descending portion 74 extends downward toward the housing 22 from the extended end of the extending portion 72, i.e. the upper end of the extending portion. The descending portion 74 spirals around the exterlding portion 72 as a center.
The end of the descending portion 14 is connected to the muffler 26 through the tank 16.
The operation of the pulse combustor lO thus constructed will now be described.
Air and fuel gas are respectively flowed into the section 48 through the tubes 66 and 68 as well as the chamber 64, the holes 42 and 44. The air and the fuel gas are mixed in the section 48, become a mixture gas, and flow into the section 49 through the hole 50. In this case, the mixture gas is flowed along the axial ~2~.6~
direction of the body 28. Then, the mixture gas is ignited by the plug 56, and is burned in the chamber 34. During combustion of the mixture gas, a flame is propagated along the flowing direction of the mixture gas, that is, l:he axial direction of the body 28. The pressure in the~ chamber 34 becomes positive due to the combustion of 1:he mixture gas. Thus, the valve 5~ is urged to block the holes 42 and 44. Therefore, the combustion gas produced in the chamber 34 is exhausted into the extending portion 72 of the tail pipe 24 which is vertical with respect to the propagating direction of the flame, that is, the axial direction of the body 28. When the combustion gas is exhausted, the pressure in the chamber 34 becomes negative. In this manner, the valve 52 is attracted to open the holes 42 and 44, with the result that air and fuel gas ~ flow into the chamber 34 through the holes 42 and 44. Simul-taneously, the combustion gas in the extending portion 72 partially flows back into the chamber 34. Since the combustion gas is hot, the mixture ~as in the chamber 34 is automatically ignited. In this case, the flowing direction of the mixture gas and the flowing direction of the combustion gas cross perpendicular to each other as shown by arrows in Fig. 3A. Therefore, the gas stream in the chamber 34 becomes a turbulent flow, and the mixture gas is thus mixed sufficiently. The combustion gas collides with the plate 30, flows 121~6~3 g reversely and is exhausted into the riser 72 at the time of combustion, as shown by arrows in Fig. 3B.
Accordingly, the mixture gas is completely burned.
Therefore, the pressure in the chamber 34 becomes sufficiently h.igh.
The performance of the combustor 10 as described above is compared with l:hat of the conventional pulse combustor having a tail pipe provided along the propa-gating direction of a f].ame. The combustor A of the above embodiment, and conventional pulse combustors B
and C of different sizes are respectively shown in Figs. 4A, 4B and 4C. The performances of combustors A, B and C are listed in the following Table:
TABLE
~Combustion amAunt ~ 6530 5230 Maximum pressure 2270 931 780 Oscillating fre- 118.5114 130.6 quency Hz CO % _0.01 to 0.1 0.01 to 0.1 As seen from the above Table, it is clear that the oscillating frequency of pulse combustor A is substan-tially equal to that of pulse combustor B having a combustion chamber of substa.ntially equal volume, and ~hat the maximum pressure of combus.or A is much higher ~2~
-- 1.0 --than that of combustor B. It is also understood that the maximum pressure of combustor A is much higher than that of combus~or C while their combustion a~ounts are substantially equal. It: is clear from this fact that the mixture o~ the air and the fuel gas is sati.sfac-torily performled and thaLt the fuel gas is completely burned in combustor A. Therefore, combustor A can perform greater high~ l.oad combustion than either combustors B or C. The CO level in the exhaust gas of combustor A is less t.han 0.01, and combustor A has eXcellent exhaust gas characteristics.
More particularly, the mounting position of the extending portion 72 of the tail pipe 24 is set, as shown in Fig. 5, to satisfy the relationship o~ the following formulae:
Q < 2-L, h > 2-D
where L represents the axial length of the chamber 34, D represents the inner diameter of the chamber 3~, Q represents the distance between the plate 30 and the central axis of the extending portion 72, and h repre-sents the axial length of the extending portion 72.
The reason for setting the formula Q < L/2 will now be described. In order to effectively utilize the reverse flow of the combustion gas produced due to the collision of the gas with the plate 30, it is preferred that the extending portion 72 be disposed at the upstream side of the chamber 3~ r that is, near to the plate 32.
~2~16~
In other words, as shown in Fig. 6~, the longer the distance for the reverse flo~ of the combustion gas, the better the air and the fuel gas will be mixed. However, when the re~erse flow distance is set too long, the s com~ustion gas is not smoothly exhausted in case of explosion and exhaustion of the gas. Thus, the space of the chamber 34 cannot be effectively utilized in case of the explosion and the combustion of the gas. There-fore, the combustion characteristics of the combustor are deteriorated. In o-ther words, if the extending portion 72 is installed clt distance Q larger than L/2 from the plate 30, as shown in Fig. 6B, the cornbustion gas accumulates in the vicinity of the plate 30, and very little is exhausted. As shown in Fig. 6C, since the extending portion 72 is disposed adjacent to the holes 42 and 44, the flow of the combustion gas which reversely flows from the extending portion 72 into the chamber 34 tends to become parallel to the mixture gas due to the negative pressure produced in the chamber 34.
Therefore, the combustion gas readily becomes stagnant in the vicinity of the plate 30, and in some cases the pulse combustor may stop generating pulses.
In order to preferably perform the suction, mixture, combustion and exhaustion of the gas to a similar degree, ~5 it s preferred to carry out in a range of Q = L/2 to L/5. However, as shown in Fig. 6D, when the distance is set to Q < L/2, the relationship of Q = Q' can be obtained at least as minimum as possible, where Q' is l/2 of the diameter of the extending portion 72. There-fore, even in the case of Q < L/5, the reverse flow of combustion gas is produced, and the mixture gas can be completely burned. Fur1:her, Fig. 7 shows the exhaust gas characteristics of 1he CO with respect to the installing position Q oi- the extending portion 72.
It can be readily understood from Fig. 7 that the relationship of Q < L/2 is preferred.
In order to effecti.vely perform the pulse oscilla-t`ion, it is understood that the relationship h > D/2 should be achieved. In other words, when the extending portion 72 is set to the relationship of h < D/2, the resistance of the combustion gas flowing in the extending portion increases. Thus, the combustor does not perform pulse oscillation or, even if it does produce a pulse oscillation, the oscillation becomes irregular. There-fore, the combustion characteristics of the combustor become extremely unfavorable.
According to the pulse combustor lO of the embodi-ment as described above, the extending portion 72 or the tail pipe 24 extends in a direction perpendicular to the propagating direction of the flame, that is, to the axial direction of the body 28. Therefore, according to the combustor lO, the air and the fuel gas can be sufficiently mixed, thereby completely burning the mixture gas. Consequently, excellent exhaust gas characteristics can be obtained in the combustor lO, high load combustion can be performed, and the combus-tion chamber can be reduced in size.
The above-described embodiment of the present invention has k,een described by way of illustration only. I'he present invention is not limited to the particular embodiment delscribed above. Various other changes and modifications may be made within the spirit and scope of the present invention. For example, as shown in Fig. 8, the first plate 30 may have a concave inner surace 76 facing the end plate 32. In this case, the reverse flow of combustion gas caused by the plate 30 can be satisfactorily performed, and the air and the fuel gas can be still further mixed.
Further, the shape of the body 28 is not limited to the cylindrical shape. For example, the body 28 may be formed in a cylindrical shape having an elliptical cross section.
~ 2 -completely burn the resulting mixture. As a resulk, the exhaust level o~ ~arbon monoxide (CO) gas in this combus-tor is significant, so that approx. 0.01 to 0.1% of the exhaust gas is Co.
The present invention has for its object the provision of a pulse combustor which is better able properly to mix air and fuel gas and able more completely to burn a mixture of the two.
According to the invention, a pulse combustor comprises a housing, having a cylindrical combustion chamber, for propagating a flame generated in the chamber in a predetermined direction; guiding means for guiding air and a fuel gas into the combustion chamber and for defining a flow path for a mixture gas of the air and the fuel gas in the predetermined direction; igniting means for i~niting the mixture gas to generate the flame with combustion gas in the comhustion chamber; and a tail pipe mounted on the housing in communication with the combustion chamber for guiding combustion gas produced in the combustion chambPr out of the combustion chamber, the tail pipe having a straight extending portion extend-ing non-tangentially from the combustion chamber in a direction perpendicular to said predetermined direction, and the extending portion being formed to satisfy the relationship of the following formula: h ~ 21D wherein h rep-esents the axial length of said straight extending portion, and D represents the diameter of said combustion chamber.
-~ ~z~
The tail pipe thus has an extending portion which extends along a direction substantially perpendicular to the propagating direction of a flame. The flow direction of th~ gas mixture and the reverse flow direction of the combustion gas from the tail pipe to the combustion chamber are thus perpenclicular, with the result that the flow of the gases in the chamber becomes turbulent.
Accordingly, the fuel gals and the air can be better mixed, the gas mixture can be c:ompletely burned, and the pressure produced in the chamber can be raised. In this manner, there is provided a pulse combustor which is capable of providing low exhaust gaLs CO gas content and of providing more complete burning of the gas mixture at high loads.
This invention can be more fully understood from lS the following detailed description when taken in conjunc-tion with the accompanying drawings, in which:
Fig. 1 is a longitudinal sectional view of a hot water supply apparatus having a pulse combustor according to an embodiment of the present invention;
Fig. 2 is a longitudinal sectional view of the pulse combustor;
Figs. 3A and 3B are sectional viewsschematically showing the operating states of the combustor;
Figs. 4A through 4C are schematic views of pulse combustors respectively showing the siæe of the presentpulse combustor and the sizes of two conventional pulse combustors of different types;
Fig. 5 is a longitudinal sectional view of the ~21~L69~3 - 3a ~
combustor schematically showing the disposition of a tail pipe and a co~ustion chamber;
. . .
~Zl~1.6~1~
Figs. 6A through 6D are sectional views sche-matically showing the operating states of pulse combustors having tail pipes provided at different positions;
Fig. 7 is a view showing the variation in the exhaust gas characteristics of co gas with respect to the instaLling positions of the tail pipe; and Fig. 8 is a sectional view schematically showing a modified embodiment of the present invention.
An embodiment of the present invention will no~ be described in more detail with reference to the accom-panying drawings.
Fig. 1 shows a hot water supplying apparatus 12 which has a pulse combustor 10 according to an embodiment of the present invention. The apparatus 12 has a supporting frame 14 and a hot water storage tank 16 of substantially cylindrical shape supported on the frame 14. The -tank 16 has a hot water supplying tube 18 moun~ed at the top end thereofl and at the bottom thereof a water supplying tube 20. The combustor ].0 is arranged in the inner bottom portion of the tank 16.
The combustor 10 comprises a housing 22 fixedly secured to the tank 12, and a tail pipe 24 extending from the housing 22 into the tank ~. The tail pipe 24 operates as a heat exchanger. The extended end of the tail pipe 24 is connected to an exhaust muffler 26 provided in the frame 14.
~2~
As shown in Fig. 2, the housing 22 of the com~ustor 10 comprises a body 28 of cylindrical shape, a first flat end plate 30 secured to the body 28 for blocking the left end of the body and a second flat end plate 32 detachably mounted on the body for blocking the right end of the body and facing the first end plate 30.
The body 28 defines a combustion chamber 34 of cylin-~drical hollow shape with the first and second plates 30 and 32 in the housing 22. The body 28 has a flange~36 at the right end thereof and the second plate 32 has a ~lang~ 38. The flange 38 of the plate 32 is clamped wi~th bol-ks 40 ko the flange 36 of the body 28. The ~lange 36 of the body 28 is fixed with the bolts 40 to the tank 16.
lS A number of air inlet holes 42:and a~number of~
fuel gas inlet holes 44 are formed through the plate 32.
The holes 42 are extended along:the axial direction of -the body 28, and are disposed along the circumferentlal direction coaxial with the body. The holes 44 are extended along the axial direction of the body 28 and are disposed along the circumferential direction coaxlal with the body. The diameter of~the hole 42 is formed larger than that of the~hole;~44.~ The holes~42 are~
disposed inside the holes 44. A throttle:~late 46 ~
confronting the plate 32 is~:provided in the chamber 34.
The plate 46 is formed in a~ circular:shape in such a manner that the peIipheral edge thereof is fixed to the :
~21~6 inner peripheral s~rface of the body 28. The interior of the chamber 34 is partitioned by the plate 46 into a mixture Section 48 commUnicating with ~he holes 44 and 42, and a combustion section 49 communicating with the tail pipe 24. A communication hole So is formed coaxial with t;he body 28, in the plate 46, thereby communicating the sections 48 and 49. In the section 48 an annular flap valve! 52 for opening and closing the hoLes 42 and 44, and an annular valve retainer 54 are arranged. The holes 42 and 44, the valve 52, the retainer 54 and the plate 46 form a part of guiding means in the pulse combustor of the present invention.
An ignition plug 56 is mounted as igniting means at the plate 32. This plug 56 has a holder 58 fixed to the center of the plate 32, and a pair of terminals 60 extendinq from the holder 58 into the chamber 34 along the axial direction of the body 28. The terminals 60 extend into the section 43 through the section 48 and the hole 50.
A cover 62 of cylindrical shape is mounted with the bolts 40 on the outer surface of the plate 32.
This cover 62 is mounted coa~ially with the body 28, and has an inner diameter substantially equal to that of the body 28. An air chamber 64 communicating with the holes 42 is defined by the cover 62 and the plate 32. An air supplying tube 66 is mounted at the cover 62 and communicates with the chamber 640 A gas su~plying - ~2~
tube 68 communicating with the holes 44 is mounted on the oUter surface of the plate 32, and extends exter-nally through the cover 62. The tubes 66 and 68 form a part of the guiding means. In Fig. 2, reference numeral 70 designates lead wires of the plug 56.
As shown in Figs. l a~d 2, the tail pipe 24 is mounted on the! body 28 of the housing 22, and includes an extending portion 72 which communicates with the chamber 34. This extending portion 72 is mounted at the lower end thereof o]n the body 28, and extends upwardly from the body 28 perpendicular to the axial direction of the body 28. The tail pipe 24 has a descending portion 74. The descending portion 74 extends downward toward the housing 22 from the extended end of the extending portion 72, i.e. the upper end of the extending portion. The descending portion 74 spirals around the exterlding portion 72 as a center.
The end of the descending portion 14 is connected to the muffler 26 through the tank 16.
The operation of the pulse combustor lO thus constructed will now be described.
Air and fuel gas are respectively flowed into the section 48 through the tubes 66 and 68 as well as the chamber 64, the holes 42 and 44. The air and the fuel gas are mixed in the section 48, become a mixture gas, and flow into the section 49 through the hole 50. In this case, the mixture gas is flowed along the axial ~2~.6~
direction of the body 28. Then, the mixture gas is ignited by the plug 56, and is burned in the chamber 34. During combustion of the mixture gas, a flame is propagated along the flowing direction of the mixture gas, that is, l:he axial direction of the body 28. The pressure in the~ chamber 34 becomes positive due to the combustion of 1:he mixture gas. Thus, the valve 5~ is urged to block the holes 42 and 44. Therefore, the combustion gas produced in the chamber 34 is exhausted into the extending portion 72 of the tail pipe 24 which is vertical with respect to the propagating direction of the flame, that is, the axial direction of the body 28. When the combustion gas is exhausted, the pressure in the chamber 34 becomes negative. In this manner, the valve 52 is attracted to open the holes 42 and 44, with the result that air and fuel gas ~ flow into the chamber 34 through the holes 42 and 44. Simul-taneously, the combustion gas in the extending portion 72 partially flows back into the chamber 34. Since the combustion gas is hot, the mixture ~as in the chamber 34 is automatically ignited. In this case, the flowing direction of the mixture gas and the flowing direction of the combustion gas cross perpendicular to each other as shown by arrows in Fig. 3A. Therefore, the gas stream in the chamber 34 becomes a turbulent flow, and the mixture gas is thus mixed sufficiently. The combustion gas collides with the plate 30, flows 121~6~3 g reversely and is exhausted into the riser 72 at the time of combustion, as shown by arrows in Fig. 3B.
Accordingly, the mixture gas is completely burned.
Therefore, the pressure in the chamber 34 becomes sufficiently h.igh.
The performance of the combustor 10 as described above is compared with l:hat of the conventional pulse combustor having a tail pipe provided along the propa-gating direction of a f].ame. The combustor A of the above embodiment, and conventional pulse combustors B
and C of different sizes are respectively shown in Figs. 4A, 4B and 4C. The performances of combustors A, B and C are listed in the following Table:
TABLE
~Combustion amAunt ~ 6530 5230 Maximum pressure 2270 931 780 Oscillating fre- 118.5114 130.6 quency Hz CO % _0.01 to 0.1 0.01 to 0.1 As seen from the above Table, it is clear that the oscillating frequency of pulse combustor A is substan-tially equal to that of pulse combustor B having a combustion chamber of substa.ntially equal volume, and ~hat the maximum pressure of combus.or A is much higher ~2~
-- 1.0 --than that of combustor B. It is also understood that the maximum pressure of combustor A is much higher than that of combus~or C while their combustion a~ounts are substantially equal. It: is clear from this fact that the mixture o~ the air and the fuel gas is sati.sfac-torily performled and thaLt the fuel gas is completely burned in combustor A. Therefore, combustor A can perform greater high~ l.oad combustion than either combustors B or C. The CO level in the exhaust gas of combustor A is less t.han 0.01, and combustor A has eXcellent exhaust gas characteristics.
More particularly, the mounting position of the extending portion 72 of the tail pipe 24 is set, as shown in Fig. 5, to satisfy the relationship o~ the following formulae:
Q < 2-L, h > 2-D
where L represents the axial length of the chamber 34, D represents the inner diameter of the chamber 3~, Q represents the distance between the plate 30 and the central axis of the extending portion 72, and h repre-sents the axial length of the extending portion 72.
The reason for setting the formula Q < L/2 will now be described. In order to effectively utilize the reverse flow of the combustion gas produced due to the collision of the gas with the plate 30, it is preferred that the extending portion 72 be disposed at the upstream side of the chamber 3~ r that is, near to the plate 32.
~2~16~
In other words, as shown in Fig. 6~, the longer the distance for the reverse flo~ of the combustion gas, the better the air and the fuel gas will be mixed. However, when the re~erse flow distance is set too long, the s com~ustion gas is not smoothly exhausted in case of explosion and exhaustion of the gas. Thus, the space of the chamber 34 cannot be effectively utilized in case of the explosion and the combustion of the gas. There-fore, the combustion characteristics of the combustor are deteriorated. In o-ther words, if the extending portion 72 is installed clt distance Q larger than L/2 from the plate 30, as shown in Fig. 6B, the cornbustion gas accumulates in the vicinity of the plate 30, and very little is exhausted. As shown in Fig. 6C, since the extending portion 72 is disposed adjacent to the holes 42 and 44, the flow of the combustion gas which reversely flows from the extending portion 72 into the chamber 34 tends to become parallel to the mixture gas due to the negative pressure produced in the chamber 34.
Therefore, the combustion gas readily becomes stagnant in the vicinity of the plate 30, and in some cases the pulse combustor may stop generating pulses.
In order to preferably perform the suction, mixture, combustion and exhaustion of the gas to a similar degree, ~5 it s preferred to carry out in a range of Q = L/2 to L/5. However, as shown in Fig. 6D, when the distance is set to Q < L/2, the relationship of Q = Q' can be obtained at least as minimum as possible, where Q' is l/2 of the diameter of the extending portion 72. There-fore, even in the case of Q < L/5, the reverse flow of combustion gas is produced, and the mixture gas can be completely burned. Fur1:her, Fig. 7 shows the exhaust gas characteristics of 1he CO with respect to the installing position Q oi- the extending portion 72.
It can be readily understood from Fig. 7 that the relationship of Q < L/2 is preferred.
In order to effecti.vely perform the pulse oscilla-t`ion, it is understood that the relationship h > D/2 should be achieved. In other words, when the extending portion 72 is set to the relationship of h < D/2, the resistance of the combustion gas flowing in the extending portion increases. Thus, the combustor does not perform pulse oscillation or, even if it does produce a pulse oscillation, the oscillation becomes irregular. There-fore, the combustion characteristics of the combustor become extremely unfavorable.
According to the pulse combustor lO of the embodi-ment as described above, the extending portion 72 or the tail pipe 24 extends in a direction perpendicular to the propagating direction of the flame, that is, to the axial direction of the body 28. Therefore, according to the combustor lO, the air and the fuel gas can be sufficiently mixed, thereby completely burning the mixture gas. Consequently, excellent exhaust gas characteristics can be obtained in the combustor lO, high load combustion can be performed, and the combus-tion chamber can be reduced in size.
The above-described embodiment of the present invention has k,een described by way of illustration only. I'he present invention is not limited to the particular embodiment delscribed above. Various other changes and modifications may be made within the spirit and scope of the present invention. For example, as shown in Fig. 8, the first plate 30 may have a concave inner surace 76 facing the end plate 32. In this case, the reverse flow of combustion gas caused by the plate 30 can be satisfactorily performed, and the air and the fuel gas can be still further mixed.
Further, the shape of the body 28 is not limited to the cylindrical shape. For example, the body 28 may be formed in a cylindrical shape having an elliptical cross section.
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pulse combustor comprising:
a housing, having a cylindrical combustion chamber, for propagating a flame generated in the chamber in a predetermined direction;
guiding means for guiding air and a fuel gas into the combustion chamber and for defining a flow path for a mixture gas of the air and the fuel gas in the predeter-mined direction;
igniting means for igniting the mixture gas to generate the flame with combustion gas in the combustion chamber; and a tail pipe mounted on the housing in communication with the combustion chamber for guiding combustion gas produced in the combustion chamber out of the combustion chamber, the tail pipe having a straight extending portion extending non-tangentially from the combustion chamber in a direction perpendicular to said predetermined direction, and the extending portion being formed to satisfy the relationship of the following formula:
wherein h represents the axial length of said straight extending portion and D represents the diameter of said combustion chamber.
a housing, having a cylindrical combustion chamber, for propagating a flame generated in the chamber in a predetermined direction;
guiding means for guiding air and a fuel gas into the combustion chamber and for defining a flow path for a mixture gas of the air and the fuel gas in the predeter-mined direction;
igniting means for igniting the mixture gas to generate the flame with combustion gas in the combustion chamber; and a tail pipe mounted on the housing in communication with the combustion chamber for guiding combustion gas produced in the combustion chamber out of the combustion chamber, the tail pipe having a straight extending portion extending non-tangentially from the combustion chamber in a direction perpendicular to said predetermined direction, and the extending portion being formed to satisfy the relationship of the following formula:
wherein h represents the axial length of said straight extending portion and D represents the diameter of said combustion chamber.
2. The pulse combustor according to Claim 1, wherein said housing comprises a body of elongate cylind-rical shape having an inner peripheral surface, a first end plate having a first inner surface and mounted at one end of the body for blocking the one end thereof, and a second end plate having a second inner surface mounted at the other end of the body and confronting the first end plate for blocking the other end of the body, said combustion chamber being defined by the inner peri-pheral surface of the body and the first and second inner surfaces of the first and second end plates respectively.
3. The pulse combustor according to Claim 2, wherein said guiding means includes air inlet holes and fuel gas inlet holes formed in the second end plate and communicating with the combustion chamber, and a valve arranged in the combustion chamber for opening and closing the air inlet holes and the fuel gas inlet holes, and wherein the mixture gas of the air and the fuel gas flows along said flow path in a direction axial to the body.
4. The pulse combustor according to Claim 3, wherein said extending portion of the tail pipe is mounted on the body, and extends from the body along a direction perpendicular to the axial direction of the body.
5. The pulse combustor according to Claim 4, wherein the inner surface of said first end plate is perpendicular to the axial direction of the body.
6. The pulse combustor according to Claim 5, wherein said guiding means includes a throttle plate arranged in the combustion chamber, one surface of said throttle plate facing the second end plate, and wherein the throttle plate partitions the combustion chamber into a mixture section communicating with the air inlet holes and the fuel gas inlet holes, and a combustion section communicating with the extending portion, and said throttle plate has a communication hole for communicating the mix-ture section with the combustion section.
7. The pulse combustor according to Claim 6, wherein said igniting means includes an ignition plug mounted at the second end plate, said ignition plug in-cluding (a) a holder mounted at the second end plate, and (b) terminals extending from the holder through the mixture section and the communication hole into the combustion section.
8. The pulse combustor according to Claim 6, wherein said guiding means includes an air supplying tube mounted at the second end plate and communicating with the air inlet holes, and a fuel gas supplying tube mounted at the second end plate and communicating with the fuel gas inlet holes.
9. The pulse combustor according to Claim 4, wherein the inner surface of said first end plate is concaved.
10. The pulse combustor according to Claim 4, wherein said extending portion of the tail pipe is mounted at the body at a position to satisfy the rela-tionship of the following formula:
where ? represents the distance between a central axis of the extending portion and the inner surface of the first end plate, and L represents an axial length of the combus-tion chamber.
where ? represents the distance between a central axis of the extending portion and the inner surface of the first end plate, and L represents an axial length of the combus-tion chamber.
11. The pulse combustor according to Claim 4, wherein said tail pipe includes a descending portion extending from the extending end of the extending portion toward the housing.
12. The pulse combustor according to Claim 11, wherein said descending portion is spirally wound around the extending portion as a centre.
13. The combustor according to Claim 1, wherein:
said guide means defines a flow path for a mixture gas of the air and the fuel gas in a direction axial to the combustion chamber, and the extending portion extends from the housing in a direction perpendicular to the axial direction of the combustion chamber.
said guide means defines a flow path for a mixture gas of the air and the fuel gas in a direction axial to the combustion chamber, and the extending portion extends from the housing in a direction perpendicular to the axial direction of the combustion chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP42082/82 | 1982-03-17 | ||
| JP4208282A JPS58158407A (en) | 1982-03-17 | 1982-03-17 | Pulsation combustion unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1211698A true CA1211698A (en) | 1986-09-23 |
Family
ID=12626119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000422260A Expired CA1211698A (en) | 1982-03-17 | 1983-02-23 | Pulse combustor |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS58158407A (en) |
| CA (1) | CA1211698A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60160315U (en) * | 1984-03-30 | 1985-10-24 | 株式会社東芝 | pulse combustion device |
-
1982
- 1982-03-17 JP JP4208282A patent/JPS58158407A/en active Pending
-
1983
- 1983-02-23 CA CA000422260A patent/CA1211698A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58158407A (en) | 1983-09-20 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |