CN105019983A - Single-node sudden-changed section tubular muffler for high-power diesel engine - Google Patents

Abstract

The invention discloses a single-node sudden-changed section tubular muffler for a high-power diesel engine. The single-node sudden-changed section tubular muffler consists of an induction passage, an expansion room and exhaust passages. The traverse section area S1 of the induction passage, the traverse section area S2 of the expansion room, the traverse section area S3 of each exhaust passage and the length l of the expansion room satisfy the equations (1)-(4) in the specification, wherein c relates to exhaust sound velocity m/s; f relates to a frequency which has a larger influence on noise among exhaust frequencies; n relates to the number of the exhaust passages; m is an odd number; and w is zero or a positive integer. Maximum noise reduction can be realized; an optimum noise reduction effect is achieved; blindness in a design process of the muffler is avoided; and a large amount of complicated and tedious trial workload is omitted.

Description

High-power diesel engine single-unit abrupt-change cross section pipe silencer

Technical field

The present invention relates to a kind of high-power diesel engine single-unit abrupt-change cross section pipe silencer, belong to diesel engine manufacturing technology field.

Background technique

Current high-power diesel engine generally adopts single-unit abrupt-change cross section pipe silencer, be made up of gas-entered passageway, expansion chamber and exhaust passage, reduce sound wave acoustic pressure by expansion chamber structure, and make sound wave produce reflection and transmission, to reach the object reducing noise, see accompanying drawing 1.For the silencing apparatus of this structure, the length of expansion chamber and each passage and expansion chamber sectional area ratio most important for the soundproof effect of silencing apparatus, the soundproof effect that the sectional area of the length and expansion chamber that strengthen expansion chamber simply might not bring.Especially, when expansion chamber length is the integral multiple of noise 1/2nd wavelength, the sound deadening capacity of silencing apparatus can be also zero on the contrary; The excessive expansion chamber of sectional area then can produce high frequency failure phenomenon, sound deadening capacity equally also can be made significantly to reduce (see " Design calcu-lation of noise control engineering " 92 pages, intelligence be just, Xu Yafen writes, hydraulic and electric engineering publishing house, in December, 1994 first edition).The optimal values of length and each sectional area ratio therefore how to choose expansion chamber is the difficult problem of puzzlement the art always.

Summary of the invention

Object of the present invention overcomes the deficiency of above-mentioned prior art exactly, provides a kind of high-power diesel engine single-unit abrupt-change cross section pipe silencer, can reach best soundproof effect.

The object of the present invention is achieved like this: a kind of high-power diesel engine single-unit abrupt-change cross section pipe silencer, is made up of gas-entered passageway, expansion chamber and exhaust passage, it is characterized in that its gas-entered passageway transverse cross-sectional profile amasss S ₁, expansion chamber transverse cross-sectional profile amasss S ₂, exhaust passage transverse cross-sectional profile amasss S ₃and expansion chamber length l must meet simultaneously:

$S_2=1.17\×{\left(\frac{c}{f}\right)}^2---\left(1\right)$

$S_3\≤\frac{S_2}{n}\≤S_1---\left(2\right)$

$l=\frac{mc}{4f}---\left(3\right)$

$l\≤\frac{(2w+1)}{2.44}\sqrt{\frac{S_2}{\mathrm{\π}}}---\left(4\right)$

In formula: c-is vented frequency larger to influence of noise in velocity of sound m/s, f-discharge frequency, n-exhaust passage number, m-odd number, w-zero or positive integer.

Technological scheme of the present invention, accurately determine each physical dimension factor of abrupt-change cross section pipe silencer with four mathematic(al) representations, maximum sound deadening capacity can be realized, reach best soundproof effect, avoid the blindness of muffler desing process, eliminate the tentative calculation workload that large amount of complex is loaded down with trivial details.

Accompanying drawing explanation

Fig. 1 is high-power abrupt-change cross section pipe silencer structural principle schematic diagram.

Be labeled as in figure: 1-gas-entered passageway; 2-expansion chamber; 3-exhaust passage group.

Embodiment

For making the object of the embodiment of the present invention, technological scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, technological scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Embodiment one

The given exhaust conditions of diesel engine is: relief opening sectional area is 0.28 square metre, frequency f=800Hz larger to influence of noise in discharge frequency, and exhaust velocity of sound c=528 meter per second, exhaust airstream speed is 10 meter per seconds, and extraction flow is 13880 cubes ms/h.Gas-entered passageway transverse cross-sectional profile according to specified criteria determination silencing apparatus amasss S ₁, expansion chamber transverse cross-sectional profile amasss S ₂, exhaust passage transverse cross-sectional profile amasss S ₃and expansion chamber length l.

The first step: determine that the gas-entered passageway transverse cross-sectional profile of silencing apparatus amasss S ₁.Get diesel exhaust gas mouth sectional area be silencing apparatus gas-entered passageway transverse cross-sectional profile amass, namely

S ₁＝0.28m ²

Second step: determine that the expansion chamber transverse cross-sectional profile of silencing apparatus amasss S ₂.Correlation values is substituted into formula (1)

$S_2=1.17\×{\left(\frac{c}{f}\right)}^2=1.17\×{\left(\frac{528}{800}\right)}^2=0.509652m$

3rd step: determine that exhaust passage transverse cross-sectional profile amasss S ₃.Consider that diesel exhaust gas airspeed is 10 meter per seconds, extraction flow is 13880 cubes ms/h, and choosing channel number is 4, correlation values is substituted into formula (2)

$\begin{array}{cc}{S}_3\≤\frac{S_2}{n}\≤S_1& S_3=\frac{S_2}{4}=\frac{0.509652}{4}=0.127413m^2\end{array}$

4th step: determine expansion chamber length l.Correlation values is substituted into formula (3), gets m=1:

$l=\frac{mc}{4f}=\frac{528}{4\×800}=0.165m$

Correlation values is substituted into formula (4), when to get w be 0, inequality right scale is minimum

$\begin{array}{cc}l\≤\frac{(2w+1)}{2.44}\sqrt{\frac{S_2}{\mathrm{\π}}}& 0.165\≤\frac{1}{2.44}\sqrt{\frac{0.509652}{3.14}}\end{array}$

Now inequality is still set up.

Finally, determine that the gas-entered passageway transverse cross-sectional profile of this silencing apparatus amasss S ₁=0.28m ², expansion chamber transverse cross-sectional profile is long-pending gets two-decimal S ₂=0.51m ², exhaust passage transverse cross-sectional profile amasss S ₃=0.1278m ², expansion chamber length l=165mm.Show that actual maximum sound deadening capacity is 6.5dB through test.

Embodiment two

The given exhaust conditions of diesel engine is: relief opening sectional area is 0.05 square metre, frequency f=800Hz that discharge frequency is larger to influence of noise, and exhaust velocity of sound c=229 meter per second, exhaust airstream speed is 10 meter per seconds, and extraction flow is 7770 cubes ms/h.Gas-entered passageway transverse cross-sectional profile according to specified criteria determination silencing apparatus amasss S ₁, expansion chamber transverse cross-sectional profile amasss S ₂, exhaust passage transverse cross-sectional profile amasss S ₃and expansion chamber length l.

The first step: determine that the gas-entered passageway transverse cross-sectional profile of silencing apparatus amasss S ₁.Get diesel exhaust gas mouth sectional area be silencing apparatus gas-entered passageway transverse cross-sectional profile amass, namely

S ₁＝0.05m ²

Second step: determine that the expansion chamber transverse cross-sectional profile of silencing apparatus amasss S ₂.Correlation values is substituted into formula (1)

$S_2=1.17\×{\left(\frac{c}{f}\right)}^2=1.17\×{\left(\frac{229}{800}\right)}^2=0.096m$

3rd step: determine that exhaust passage transverse cross-sectional profile amasss S ₃.Consider that diesel exhaust gas airspeed is 10 meter per seconds, extraction flow is 7770 cubes ms/h, and choosing channel number is 3, correlation values is substituted into formula (2)

$\begin{array}{cc}{S}_3\≤\frac{S_2}{n}\≤S_1& S_3=\frac{S_2}{3}=\frac{0.096}{3}=0.032m^2\end{array}$

4th step: determine expansion chamber length l.Related data is substituted into formula (3), get m=1

$l=\frac{mc}{4f}=\frac{229}{4\×800}=0.07156m$

Correlation values is substituted into formula (4), when to get w be 0, inequality right scale is minimum

$\begin{array}{cc}l\≤\frac{(2w+1)}{2.44}\sqrt{\frac{S_2}{\mathrm{\π}}}& 0.07156\≤\frac{1}{2.44}\sqrt{\frac{0.096}{3.14}}\end{array}$

Now inequality is still set up.

Finally, determine that the gas-entered passageway transverse cross-sectional profile of this silencing apparatus amasss S ₁=0.05m ², expansion chamber transverse cross-sectional profile amasss S ₂=0.096m ², exhaust passage transverse cross-sectional profile amasss S ₃=0.032m ², expansion chamber length l=71.56mm.Show that actual maximum sound deadening capacity is 4.4dB through test.

Last it is noted that above embodiment is only in order to illustrate technological scheme of the present invention, be not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technological scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technological scheme.

Claims (1)

1. a high-power diesel engine single-unit abrupt-change cross section pipe silencer, is made up of gas-entered passageway, expansion chamber and exhaust passage, it is characterized in that its gas-entered passageway transverse cross-sectional profile amasss S ₁, expansion chamber transverse cross-sectional profile amasss S ₂, exhaust passage transverse cross-sectional profile amasss S ₃and expansion chamber length l must meet simultaneously:

$S_2=1.17\×{\left(\frac{c}{f}\right)}^2---\left(1\right)$

$S_3\≤\frac{S_2}{n}\≤S_1---\left(2\right)$

$l=\frac{mc}{4f}---\left(3\right)$

$l\≤\frac{(2w+1)}{2.44}\sqrt{\frac{S_2}{\mathrm{\π}}}---\left(4\right)$

In formula: c-is vented frequency larger to influence of noise in velocity of sound m/s, f-discharge frequency, n-exhaust passage number, m-odd number, w-zero or positive integer.