CN106644387B - Inner wall of the pipe frictional resistant coefficient test device and test method under unsteady flow - Google Patents
Inner wall of the pipe frictional resistant coefficient test device and test method under unsteady flow Download PDFInfo
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Abstract
Inner wall of the pipe frictional resistant coefficient test device under unsteady flow of the present invention changes over time the wave-height gauge of situation including high level water tank, low-level cistern, for measuring Water in Water Tanks position, for measuring the pressure sensor of water flow pressure suffered by tested pipeline tube wall and for data record, processing and the computer of storage；The high level water tank is provided with apopore, and the low-level cistern is provided with inlet opening, and is equipped with the sluice that can open or close inlet opening；The wave-height gauge is made of two wave height acquisition probes and a wave height processing instrument, and wave height processing instrument is connect with computer；The pressure sensor is made of pressure acquisition devices and pressure transmitter, and pressure transmitter is connect with computer.Additionally provide inner wall of the pipe frictional resistant coefficient test method under the unsteady flow using test device of the present invention.Device and method of the present invention can quickly and accurately test out the frictional resistant coefficient of inner wall of the pipe corresponding to different liquids flow velocity under unsteady flow.
Description
Technical field
The invention belongs to liquid measurement technology fields, the in particular to test device and survey of inner wall of the pipe frictional resistant coefficient
Method for testing.
Background technique
In pipeline liquid process, inner wall of the pipe frictional resistant coefficient is characterization liquid drag size suffered by the journey
One dimension.Inner wall of the pipe frictional resistant coefficient when being laminar flow in pipeline has theoretical formula method, but inner wall of the pipe is disorderly
Inner wall of the pipe frictional resistant coefficient when stream there is no theoretical formula method so far, need to obtain by testing test.Existing measurement
The method of inner wall of the pipe frictional resistant coefficient is that steady flow is passed through into tested pipeline, and the flow of pipeline is obtained with flow measurement, is used
Pressure-measuring pipe or pressure sensor measure head loss, then calculate inner wall of the pipe frictional resistant coefficient.Due to this method one
The secondary inner wall of the pipe frictional resistant coefficient that can only be measured under a particular liquid flow velocity, thus it is different in flow rate right to obtain liquid
The inner wall of the pipe frictional resistant coefficient answered, the especially frictional resistant coefficient under turbulent-flow conditions then need to carry out many experiments, not only
Operating time is long, and test accuracy also have it is to be hoisted.
Summary of the invention
In view of the above-mentioned deficiencies in the prior art, it is an object of the present invention to provide inner wall of the pipe on-way resistance under a kind of unsteady flow
The test device and test method of coefficient, quickly and accurately to test out under unsteady flow corresponding to different liquids flow velocity
Inner wall of the pipe frictional resistant coefficient.
Inner wall of the pipe frictional resistant coefficient test device under unsteady flow of the present invention, including high level water tank, low water
Position water tank changes over time the wave-height gauge of situation for measuring Water in Water Tanks position, for measuring water flow suffered by tested pipeline tube wall
The pressure sensor of pressure and for data record, processing and the computer of storage；The one side wall lower part of the high level water tank
It is provided with apopore, the one side wall lower part of the low-level cistern is provided with inlet opening, and is equipped with and can open or close into water
The sluice in hole, low-level cistern is provided with drainage hole towards opposite sidewall bottom with the side wall of setting inlet opening, and is equipped with
Have when water storage for blocking the plug of drainage hole；The wave-height gauge is by two wave height acquisition probes and a wave height processing instrument group
When at, test, two wave height acquisition probes are separately mounted in high level water tank and low-level cistern, and pass through transmission line respectively
It is connect with wave height processing instrument, the wave height processing instrument is connect with computer；The pressure sensor is by pressure acquisition devices and pressure
Transmitter composition, the quantity of pressure tap being arranged in the quantity and tested pipeline of pressure acquisition devices is identical, and when test, each pressure is adopted
Storage is separately mounted in the pressure tap being arranged on tested pipeline, and is connect by transmission line with pressure transmitter, the pressure
Transmitter is connect with computer.
Inner wall of the pipe frictional resistant coefficient test device under above-mentioned unsteady flow, low-level cistern setting inlet opening
Side wall is sandwich, and the sluice is made of gate and the carrying handle that is connected on gate, gate installation in the interlayer of side wall,
The handheld terminal of carrying handle extends the interlayer of side wall.
Inner wall of the pipe frictional resistant coefficient test device under above-mentioned unsteady flow, the set water outlet of high level water tank lower sidewall
The central axis in sidewall width direction and intersection where the center line in hole and the apopore, set by low-level cistern lower sidewall
The central axis in sidewall width direction and intersection, low-level cistern sidewall bottom where the center line of inlet opening and the inlet opening
The central axis in sidewall width direction and intersection where the center line of set drainage hole and the drainage hole.
Inner wall of the pipe frictional resistant coefficient test device under above-mentioned unsteady flow, the aperture of apopore set by high level water tank
Aperture=1.6d1~2d1 of inlet opening set by=low-level cistern, the center line and high water level of apopore set by high level water tank
The center line and low-level cistern bottom wall inner surface of inlet opening set by spacing=low-level cistern between tank bottom wall inner surface
Between spacing=2d1~3d1, aperture=0.6d1~d1 of drainage hole set by low-level cistern, the set draining of low-level cistern
Spacing between the center line and low-level cistern bottom wall inner surface in hole is equal to the aperture of the drainage hole, and the d1 is tested pipeline
Internal diameter, unit cm.
Inner wall of the pipe frictional resistant coefficient test device under above-mentioned unsteady flow, the length a1=width b1 of high level water tank
=50~70cm, height c1=120~200cm of high level water tank；The length a2=width b2=30 of low-level cistern~
50cm, height c2=90~150cm of low-level cistern.
Inner wall of the pipe frictional resistant coefficient test method under unsteady flow of the present invention is filled using test of the present invention
It sets, steps are as follows:
1. the processing of tested pipeline
Horn mouth is processed at the both ends of tested pipeline, is processing a survey pressure respectively on the bell-mouthed tube wall of two close end
The length L in hole, tested pipeline is controlled in 200~300cm, bell-mouthed maximum outside diameter d 3=1.6d1~2d1, formula, described
D1 is the internal diameter of tested pipeline, unit cm；
2. the combination of tested pipeline and test device
High level water tank, low-level cistern in test device is placed on same elevation, and sets high level water tank
The side wall for having the side wall of apopore to be equipped with inlet opening with low-level cistern is in opposite orientation, by the both ends loudspeaker of tested pipeline
In the water outlet that mouth is separately fixed at high level water tank by the way of bonding and in the water inlet of low-level cistern；
Two wave height acquisition probes in test device are separately mounted in high level water tank and low-level cistern, and point
Two wave height acquisition probes are not connect by transmission line with wave height processing instrument, wave height processing instrument is connect with computer；
Install the pressure acquisition devices in test device respectively in each pressure tap of tested pipeline, and by pressure acquisition devices
It is connect by transmission line with pressure transmitter, pressure transmitter is connect with computer；
3. the debugging of test device
The inlet opening that sluice closes low-level cistern is operated, and blocks the drainage hole of low-level cistern with plug, is then divided
It is not filled the water into high level water tank and low-level cistern, the water injection rate of low-level cistern controls the water level h2 in low-level cistern
=4d1~6d1, the water level h1 that the water injection rate of high level water tank controls in high level water tank meet inequality h2 < h1≤
0.8c1, in formula, the d1 is the internal diameter of tested pipeline, the height of c1 high level water tank, then operation sluice opens low level water afterwards
The inlet opening of case, and record time t needed for the water level in high level water tank and low-level cistern reaches balance1, after rear opening
The drainage hole of low-level cistern, by high level water tank and low-level cistern water all discharge after close low-level cistern into
Water hole and drainage hole；
4. test operation
The inlet opening that sluice closes low-level cistern is operated, and blocks the drainage hole of low-level cistern with plug, to Gao Shui
Be injected separately into position water tank and low-level cistern with step 3. identical water, make high level water tank and low-level cistern formed with
Step 3. identical water-head, then powers on, the frequency acquisition and acquisition time of setting pressure sensor, wave-height gauge, institute
State acquisition time be set as step 3. in water level in high level water tank and low-level cistern reach balance needed for time t1, after
The inlet opening of low-level cistern is opened afterwards, and opens pressure sensor, wave-height gauge while opening low-level cistern inlet opening
Beginning work sends computer, the high level water tank that computer will receive to after collected signal is handled and converted
The number that water flow pressure suffered by the data and tested pipeline tube wall changed over time with the water level in low-level cistern changes over time
According to being handled and saved；
5. the acquisition of frictional resistant coefficient
The data that the water level in high level water tank and low-level cistern changes over time are fitted to respectively by computer
Polynomial function respectively obtains the flow velocity of two Water in Water Tanks stream, then root by obtain two polynomial functions to time derivation
According to the flow rate of water flow in high level water tank by continuity equation v1A1=v2A2Acquire the flow velocity v of water flow in tested pipelinehg, according to
Flow rate of water flow in low-level cistern is by continuity equation v1A1=v2A2Acquire the flow velocity v of water flow in tested pipelinedg, by vhgWith
vdgIt is compared, when the absolute value of two differences is less than or equal to 10cm/s, then with vhgOr vdgAs water in tested pipeline
The flow velocity of stream indicates that test macro is wrong when the absolute value of two differences is greater than 10cm/s, then needs to check test macro,
It is tested again, in the continuity equation, v1For the flow velocity of water flow in high level water tank or low-level cistern, v2It is tested
The flow velocity of water flow in pipeline, A1For the floor space of high level water tank or low-level cistern, A2For the cross section face of tested pipeline inner hole
Product；According to water flow pressure data suffered by the same time tested pipeline tube wall of acquisition and pipeline water flow flow speed data by there is pressure pipe
The road unsteady flow equation of motion finds out tested pipeline frictional head loss, then finds out tested pipeline on-way resistance by Darcy formula
Coefficient；
The pressure conduit unsteady flow equation of motion is as follows:
In formula, z1And z2The respectively average bit energy of pressure conduit arbitrary cross-section 1 and section 2,WithIt is respectively disconnected
The average pressure energy in face 1 and section 2,WithThe respectively mean kinetic energy of section 1 and section 2,For energy damage
It loses,For inertial hydraulic head；
The Darcy formula is as follows:
In formula, hfIt is frictional head loss, λ is frictional resistant coefficient, and d is tested pipeline internal diameter, and g is acceleration of gravity, l
It is the distance between two pressure taps.
Above-mentioned Darcy formula, pressure conduit unsteady flow equation of motion water breakthrough power reckoner second edition, Wu Chigong chief editor the
4 editions.
In the above method, the pressure tap processed on the tube wall of tested pipeline both ends it is equal with the spacing of both ends flare end and
It is L2=2d1。
Compared with prior art, the invention has the following advantages:
1. the device is not only the present invention provides a kind of test device of inner wall of the pipe frictional resistant coefficient under unsteady flow
Structure is simple, and convenient for assembling, easily operated.
2. using test device of the present invention and test method, primary test can quickly and accurately test out one
Pipe'resistance coefficient in flow rates.
Detailed description of the invention
Fig. 1 be unsteady flow of the present invention under inner wall of the pipe frictional resistant coefficient test device structural schematic diagram and
The combination diagram of tested pipeline and the test device.
Fig. 2 is the structural schematic diagram of high water tank.
Fig. 3 is the structural schematic diagram of lower water box.
Fig. 4 is the schematic diagram of tested pipeline.
The relation curve that water level changes over time in the high level water tank, low-level cistern of test device when Fig. 5 is test.
The relation curve that water flow pressure suffered by tested pipeline tube wall changes over time when Fig. 6 is test.
Fig. 7 is the frictional resistant coefficient of tested pipeline and the relation curve of water flow in pipeline (liquid) flow velocity.
In figure, 1-high level water tank, 2-low-level cisterns, 3-1-wave height acquisition probe, 3-2-wave height processing instrument, 4
Sluice, the apopore of 5-high level water tanks, the inlet opening of 6-low-level cisterns, the drainage hole of 7-low-level cisterns, 8-1-
Pressure acquisition devices, 8-2-pressure transmitter, 9-computers, 10-tested pipelines, 10-1-horn mouth, 10-2-pressure tap.
Specific embodiment
Below by embodiment to the test device of inner wall of the pipe frictional resistant coefficient under unsteady flow of the present invention and
Test method is described further.
Embodiment 1
Inner wall of the pipe frictional resistant coefficient test device structure under unsteady flow described in the present embodiment as shown in Figure 1-3, packet
It includes high level water tank 1, low-level cistern 2, change over time the wave-height gauge of situation for measuring Water in Water Tanks position, for measuring quilt
Survey the pressure sensor of water flow pressure suffered by pipe wall and for data record, processing and the computer of storage 9；The Gao Shui
The right side wall lower part of position water tank 1 is provided with apopore 5, where the center line of apopore and the apopore in sidewall width direction
Heart line is vertical and intersects；The left side wall lower part of the low-level cistern 2 is provided with inlet opening 6, and right side wall bottom is provided with draining
Hole 7 and when equipped with water storage for blocking the plug of drainage hole, sidewall width side where the center line of inlet opening 7 and the inlet opening
To central axis and intersection, the central axis in sidewall width direction where the center line of drainage hole 7 and the drainage hole is simultaneously
Intersection；The left side wall of the low-level cistern is sandwich and is equipped with the sluice 4 that can open or close inlet opening 6, described
Sluice 4 is made of gate and the carrying handle being connected on gate, and in the interlayer of left side wall, the handheld terminal of carrying handle extends gate installation
The interlayer of left side wall out.
The wave-height gauge is condenser type wave-height gauge, originates from China Water Resources & Hydropower Science Research Institute, range 150cm, and water level misses
Difference < ± 1%F.S (hydrostatic level), the wave-height gauge are made of two wave height acquisition probe 3-1 and a wave height processing instrument 3-2, test
When, two wave height acquisition probes are separately mounted in high level water tank and low-level cistern, and pass through transmission line and wave height respectively
Processing instrument connection, the wave height processing instrument are connect with computer.
The pressure sensor is CY200 digital pressure sensor, by pressure acquisition devices 8-1 and pressure transmitter 8-2 group
At, 1 time/hour~1000 time of sample rate/second adjustable；Pressure type gauge pressure (0~60Mpa), absolute pressure (0~50Kpa), negative pressure (-
100Kpa~1Mpa), synthesis precision 0.1%FS；The survey pressure being arranged in the quantity and tested pipeline 10 of the pressure acquisition devices 8-1
The quantity of hole 10-2 is identical, and when test, each pressure acquisition devices are separately mounted in the pressure tap being arranged on tested pipeline, and are passed through
Transmission line is connect with pressure transmitter, and the pressure transmitter is connect with computer.
The computer 9 is common computer, is equipped with software matched with wave-height gauge and matched with pressure sensor
Software.
In the present embodiment, the high level water tank 1, the size of low-level cistern 2 in test device are as follows:
High level water tank: long a1=50cm wide b1=50cm, high c1=150cm
Low-level cistern: long a2=30cm wide b2=30cm, high c2=100cm
Aperture=1.7d1 of inlet opening 6 set by aperture=low-level cistern of apopore 5 set by high level water tank, Gao Shui
The set water inlet of spacing=low-level cistern between the center line and high level water tank bottom wall inner surface of apopore 5 set by the water tank of position
Spacing=2.5d1 between the center line and low-level cistern bottom wall inner surface in hole 6, the hole of drainage hole 7 set by low-level cistern
Diameter=0.8d1, the spacing between the center line and low-level cistern bottom wall inner surface of drainage hole set by low-level cistern is equal to should
The aperture of drainage hole, the d1 are the internal diameter of tested pipeline, unit cm.
Embodiment 2
The method for testing inner wall of the pipe frictional resistant coefficient under unsteady flow using test device described in embodiment 1, step
It is as follows:
1. the processing of tested pipeline
Tested pipeline 10 is PVC pipeline, the length L=200cm of pipeline, internal diameter d1=5cm adds the both ends of tested pipeline
Work is L in the spacing away from both ends flare end at horn mouth 10-1, bell-mouthed maximum outside diameter d3=1.6d1=8cm2=
2d1A pressure tap 10-2 is processed on the tube wall of=10cm respectively, the aperture of each pressure tap is 0.8cm；
2. the combination of tested pipeline and test device
High level water tank 1, low-level cistern 2 in test device is placed on same elevation, and makes high level water tank
The left side wall that right side wall and low-level cistern equipped with apopore 5 are equipped with inlet opening 6 is in opposite orientation, by tested pipeline
In the apopore that both ends horn mouth is separately fixed at high level water tank 1 by the way of the bonding and inlet opening of low-level cistern 2
In；
Two wave height acquisition probe 3-1 in test device are separately mounted in high level water tank and low-level cistern,
And respectively connect two wave height acquisition probes with wave height processing instrument 3-2 by transmission line, wave height processing instrument and computer 9 are connected
It connects；
Install the pressure acquisition devices 8-1 in test device respectively in each pressure tap 10-2 of tested pipeline, and will pressure
Power collector is connect by transmission line with pressure transmitter 8-2, and pressure transmitter is connect with computer 9；
3. the debugging of test device
The inlet opening 6 that sluice closes low-level cistern is operated, and blocks the drainage hole 7 of low-level cistern with plug, then
It is filled the water respectively into high level water tank 1 and low-level cistern 2, the water injection rate of low-level cistern controls the water in low-level cistern
The water injection rate of position h2=20cm, high level water tank 1 are controlled in high level water tank water level h1=110cm, then operation sluice is opened afterwards
The inlet opening of low-level cistern, and record time t needed for the water level in high level water tank 1 and low-level cistern 2 reaches balance1
=2min will be closed after the rear drainage hole 7 for opening low-level cistern after the water in high level water tank and low-level cistern all discharge
Close inlet opening 6 and the drainage hole 7 of low-level cistern；
4. test operation
The inlet opening 6 that sluice closes low-level cistern is operated, and blocks the drainage hole 7, Xiang Gao of low-level cistern with plug
Be injected separately into level water tank 1 and low-level cistern 2 with step 3. identical water, make high level water tank 1 and low-level cistern 2
Formed with step 3. identical water-head, then power on, the frequency acquisition that pressure sensor apparatus is arranged is 1ms, acquisition
Time is 2min, and the frequency acquisition of wave-height gauge is 2ms, acquisition time 2min；After the rear inlet opening for opening low-level cistern, and
Pressure sensor, wave-height gauge is set to start to work while opening low-level cistern inlet opening, at collected signal
Computer is sent to after reason and conversion, and computer becomes the water level in the high level water tank and low-level cistern that receive at any time
The data that water flow pressure suffered by the data and tested pipeline tube wall of change changes over time are handled and are saved, and typing excel
Table,；
5. the acquisition of frictional resistant coefficient
By computer, by data that wave-height gauge measures, (water level in high level water tank and low-level cistern becomes I at any time
The data of change) and time match at polynomial function, the polynomial function of high level water tank SEA LEVEL VARIATION is following (1-1) formulas:
Y=0.0539t2-2.4878t+0.9504 (1-1)
Wherein t is the time, and y is that water level adds up changing value；
The polynomial function of low-level cistern SEA LEVEL VARIATION is following (1-2) formulas:
Y=-0.0123t3-0.0237t2+6.7311t-1.8258 (1-2)
Wherein t is the time, and y is that water level adds up changing value；
The curve of above-mentioned polynomial function is as shown in Figure 5.
Formula (1-1) to time derivation, is obtained the situation of change of flow rate of water flow in high level water tank by II, due to two water tanks
Water velocity it is contrary (high level water tank water velocity is downward, and low-level cistern water velocity is upward, contrary, and
Sign indicates direction, compares so the opposite number of a speed is taken to can be carried out size), opposite number is taken to water velocity,
Obtain the variation expression formula of flow rate of water flow in high level water tank:
vh=-0.10478t+2.4878 (1-3)
Wherein t is time, vhFor flow rate of water flow changing value in high level water tank；
By formula (1-2) to time derivation, the variation expression formula of flow rate of water flow in low-level cistern is obtained:
vd=-0.0369t2-0.0474t+6.7311 (1-4)
Wherein t is time, vdFor flow rate of water flow changing value in low-level cistern.
III is according to the flow rate of water flow in low-level cistern by continuity equation v1A1=v2A2(1-5) seeks water in tested pipeline
The flow velocity v of streamdg
By A1=a2b2,v1=vd, bring (1-5) into and obtain
It obtains
In formula, vdgFlow rate of water flow in the tested pipeline acquired for low-level cistern SEA LEVEL VARIATION, a2For low-level cistern
Bottom side length, b2The bottom edge of low-level cistern is wide, d1For the internal diameter of tested pipeline；
By a2=30cm, b2=30cm, d1=5cm and formula vd=-0.0369t2- 0.0474t+6.7311 (1-4) is brought into
Formula (1-7) acquires tested pipeline water velocity expression way
vdg=-1.69t2-2.17t+308.68 (1-8)
According to the flow rate of water flow in high level water tank by continuity equation v1A1=v2A2(1-5) seeks water flow in tested pipeline
Flow velocity vhgBy A1=a1b1,v1=vh, bring (1-5) into and obtain
It obtains
Wherein vhgFlow rate of water flow in the tested pipeline acquired for high level water tank SEA LEVEL VARIATION, a1For the bottom of high level water tank
Side length, b1The bottom edge of high level water tank is wide, d1For the internal diameter for testing pipeline；
By a1=50cm, b1=50cm, d1=5cm and formula vh=-0.10478t+2.4878 (1-3) brings formula (1- into
10), acquiring water velocity expression way in tested pipeline is
vhg=-13.3t+316.91 (1-11)
Since the water velocity of two water tanks is contrary, for the ease of comparing the pipe flow speed that two water tanks acquire, by 1-11
Opposite number is taken to obtain
vhg=13.3t-316.91 (1-11)
By the v at (1-11) and (1-8) the formula same time point calculatedhgAnd vdgIt is compared, if the absolute value of two differences
Less than or equal to 10cm/s, then with vhgOr vdgAs the flow velocity of water flow in tested pipeline, if the absolute value of two differences is greater than
10cm/s indicates that test macro is wrong, then needs to check test macro, be tested again.
Flow rate of water flow in water flow pressure data and tested pipeline suffered by same time tested pipeline tube wall of the IV by acquisition
Data find out tested pipeline frictional head loss, pressure conduit unsteady flow campaign side by the pressure conduit unsteady flow equation of motion
Journey is shown in following formula:
In formula, z1And z2The respectively average bit energy of pressure conduit arbitrary cross-section 1 and section 2,WithIt is respectively disconnected
The average pressure energy in face 1 and section 2,WithThe respectively mean kinetic energy of section 1 and section 2,For energy damage
It loses,For inertial hydraulic head；
Without local head loss between two test points of tested pipeline, then all frictional head loss of head loss,
1-12 is converted to obtain
Wherein hfFor the frictional head loss of tested pipeline；
Since the elevation of two test points is identical, then average bit can be identical, and same uncompressed pipe flow speed is identical, so average
Kinetic energy is identical, obtains
Water flow pressure suffered by tested pipeline tube wall that two test points measure is brought into (1-14) formula, by water flow in tested pipeline
The expression formula (1-11 or 1-8 formula) of flow velocity acquires h to time derivationf, recycle Darcy formula
It obtains
In formula, λ is the frictional resistant coefficient of tested pipeline inner wall, and d is tested pipeline internal diameter, and g is acceleration of gravity, and l is
The distance between two measuring points (pressure tap) of tested pipeline；
By d=5cm, g=9.8m2/s, l=L-2*L2=180cm brings (1-16) into, acquires frictional resistant coefficient λ and quilt
Flow rate of water flow v relation curve in test tube road, as shown in Figure 7.
Claims (10)
1. inner wall of the pipe frictional resistant coefficient test method under unsteady flow, it is characterised in that the test device used includes Gao Shui
It is position water tank (1), low-level cistern (2), the wave-height gauge for changing over time for measuring Water in Water Tanks position situation, tested for measuring
The pressure sensor of water flow pressure suffered by pipe wall and for data record, processing and the computer of storage (9)；The Gao Shui
The one side wall lower part of position water tank (1) is provided with apopore (5), and the one side wall lower part of the low-level cistern (2) is provided with into water
Hole (6), and the sluice (4) that can open or close inlet opening is installed, the side wall court with setting inlet opening of low-level cistern (2)
Opposite side bottom is provided with drainage hole (7), and for blocking the plug of drainage hole when equipped with water storage；
The wave-height gauge is made of two wave height acquisition probes (3-1) and a wave height processing instrument (3-2), when test, two waves
High acquisition probe is separately mounted in high level water tank and low-level cistern, and is connected respectively by transmission line and wave height processing instrument
It connects, the wave height processing instrument is connect with computer；
The pressure sensor is made of pressure acquisition devices (8-1) and pressure transmitter (8-2), the number of pressure acquisition devices (8-1)
Measure identical as the quantity of pressure tap (10-2) being arranged on tested pipeline (10), when test, each pressure acquisition devices are separately mounted to
In the pressure tap being arranged on tested pipeline, and it is connect by transmission line with pressure transmitter, the pressure transmitter and computer
Connection；
Steps are as follows:
1. the processing of tested pipeline
Horn mouth (10-1) is processed at the both ends of tested pipeline (10), is processing one respectively on the bell-mouthed tube wall of two close end
A pressure tap (10-2), the length L control of tested pipeline in 200~300cm, bell-mouthed maximum outside diameter d 3=1.6d1~
2d1, in formula, the d1 is the internal diameter of tested pipeline, unit cm；
2. the combination of tested pipeline and test device
High level water tank (1), low-level cistern (2) in test device is placed on same elevation, and makes high level water tank
The side wall that side wall and low-level cistern equipped with apopore (5) are equipped with inlet opening (6) is in opposite orientation, by tested pipeline
Both ends horn mouth using bonding by the way of be separately fixed at high level water tank (1) apopore in and low-level cistern (2) into
In water hole；
Two wave height acquisition probes (3-1) in test device are separately mounted in high level water tank and low-level cistern, and
Two wave height acquisition probes are connect by transmission line with wave height processing instrument (3-2) respectively, by wave height processing instrument and computer (9)
Connection；
Install the pressure acquisition devices (8-1) in test device respectively in each pressure tap (10-2) of tested pipeline, and will pressure
Power collector is connect by transmission line with pressure transmitter (8-2), and pressure transmitter is connect with computer (9)；
3. the debugging of test device
The inlet opening (6) that sluice closes low-level cistern is operated, and blocks the drainage hole (7) of low-level cistern with plug, then
The water injection rate of the water filling into high level water tank (1) and low-level cistern (2) respectively, low-level cistern controls in low-level cistern
Water level h2=4d1~6d1, the water level h1 that the water injection rate of high level water tank (1) controls in high level water tank meets inequality
H2 < h1≤0.8c1, in formula, the d1 is the internal diameter of tested pipeline, the height of c1 high level water tank, then operation sluice is opened afterwards
The inlet opening of low-level cistern, and record the water level in high level water tank (1) and low-level cistern (2) reach balance needed for when
Between t1, after the rear drainage hole (7) for opening low-level cistern, will be closed after the water in high level water tank and low-level cistern all discharge
Close inlet opening (6) and the drainage hole (7) of low-level cistern；
4. test operation
The inlet opening (6) that sluice closes low-level cistern is operated, and blocks the drainage hole (7) of low-level cistern, Xiang Gao with plug
Be injected separately into level water tank (1) and low-level cistern (2) with step 3. identical water, make high level water tank (1) and low water
Position water tank (2) formed with step 3. identical water-head, then power on, the acquisition frequency of setting pressure sensor, wave-height gauge
Rate and acquisition time, the acquisition time be set as step 3. in water level in high level water tank (1) and low-level cistern (2) reach
Time t needed for balance1, after the rear inlet opening for opening low-level cistern, and while opening low-level cistern inlet opening
So that pressure sensor, wave-height gauge is started to work, sends computer, computer after collected signal is handled and converted to
Water suffered by the data and tested pipeline tube wall that water level in the high level water tank and low-level cistern that receive is changed over time
The data that stream pressure changes over time are handled and are saved；
5. the acquisition of frictional resistant coefficient
The data that the water level in high level water tank and low-level cistern changes over time are fitted to respectively by computer multinomial
Formula function respectively obtains the flow velocity of two Water in Water Tanks stream, further according to height by obtain two polynomial functions to time derivation
Flow rate of water flow in level water tank is by continuity equation v1A1=v2A2Acquire the flow velocity v of water flow in tested pipelinehg, according to low water
Flow rate of water flow in the water tank of position is by continuity equation v1A1=v2A2Acquire the flow velocity v of water flow in tested pipelinedg, by vhgAnd vdgInto
Row compares, when the absolute value of two differences is less than or equal to 10cm/s, then with vhgOr vdgAs water flow in tested pipeline
Flow velocity indicates that test macro is wrong when the absolute value of two differences is greater than 10cm/s, then needs to check test macro, again
It is tested, in the continuity equation, v1For the flow velocity of water flow in high level water tank or low-level cistern, v2For tested pipeline
The flow velocity of middle water flow, A1For the floor space of high level water tank or low-level cistern, A2For the cross-sectional area of tested pipeline inner hole,
According to water flow pressure data suffered by the same time tested pipeline tube wall of acquisition and tested pipeline flow rate of water flow data by there is pressure
The transient pipe flow equation of motion finds out tested pipeline frictional head loss, then finds out tested pipeline by Darcy formula and hinder along journey
Force coefficient；
The pressure conduit unsteady flow equation of motion is as follows:
In formula, z1And z2The respectively average bit energy of pressure conduit arbitrary cross-section 1 and section 2,WithRespectively 1 He of section
The average pressure energy of section 2,WithThe respectively mean kinetic energy of section 1 and section 2,For energy loss,
For inertial hydraulic head；
The Darcy formula is as follows:
In formula, hfIt is frictional head loss, λ is frictional resistant coefficient, and d is tested pipeline internal diameter, and g is acceleration of gravity, and l is two
The distance between a pressure tap.
2. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 1, it is characterised in that described
The side wall that inlet opening (6) are arranged in low-level cistern is sandwich, and the sluice (4) is by gate and the carrying handle being connected on gate
It constitutes, for gate installation in the interlayer of side wall, the handheld terminal of carrying handle extends the interlayer of side wall.
3. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 1 or claim 2, it is characterised in that high
The central axis in sidewall width direction where the center line and the apopore of apopore set by level water tank lower sidewall (5) is simultaneously
Intersect, the center in sidewall width direction where the center line of inlet opening (6) set by low-level cistern lower sidewall and the inlet opening
Line is vertical and intersects, sidewall width side where the center line and the drainage hole of drainage hole set by low-level cistern sidewall bottom (7)
To central axis and intersection.
4. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 1 or claim 2, it is characterised in that high
Aperture=1.6d1~the 2d1 of inlet opening (6), high water level set by aperture=low-level cistern of apopore set by level water tank (5)
Inlet opening set by spacing=low-level cistern between the center line and high level water tank bottom wall inner surface of apopore set by water tank
Center line and low-level cistern bottom wall inner surface between spacing=2d1~3d1, drainage hole (7) set by low-level cistern
Aperture=0.6d1~d1, the spacing between the center line and low-level cistern bottom wall inner surface of drainage hole set by low-level cistern
Equal to the aperture of the drainage hole, the d1 is the internal diameter of tested pipeline, unit cm.
5. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 3, it is characterised in that Gao Shui
Aperture=1.6d1~2d1 of inlet opening (6) set by aperture=low-level cistern of apopore (5) set by the water tank of position, high water level water
Inlet opening set by spacing=low-level cistern between the center line and high level water tank bottom wall outer surface of apopore set by case
Spacing=2d1~3d1 between center line and low-level cistern bottom wall outer surface, the hole of drainage hole (7) set by low-level cistern
Diameter=0.6d1~d1, the spacing etc. between the center line and low-level cistern bottom wall outer surface of drainage hole set by low-level cistern
In the aperture of the drainage hole, in formula, the d1 is the internal diameter of tested pipeline, unit cm.
6. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 1 or claim 2, it is characterised in that high
Length the a1=width b1=50~70cm, height c1=120~200cm of high level water tank (1) of level water tank (1)；Low water
Length the a2=width b2=30~50cm, height c2=90~150cm of low-level cistern (2) of position water tank (2).
7. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 1 or claim 2, it is characterised in that quilt
The pressure tap (10-2) processed on survey pipe ends tube wall is equal with the spacing of both ends flare end and is L2=2d1。
8. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 3, it is characterised in that tested
The pressure tap (10-2) processed on pipe ends tube wall is equal with the spacing of both ends flare end and is L2=2d1。
9. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 4, it is characterised in that tested
The pressure tap (10-2) processed on pipe ends tube wall is equal with the spacing of both ends flare end and is L2=2d1。
10. inner wall of the pipe frictional resistant coefficient test method under unsteady flow according to claim 5, it is characterised in that tested
The pressure tap (10-2) processed on pipe ends tube wall is equal with the spacing of both ends flare end and is L2=2d1。
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| CN113092314A (en) * | 2021-03-19 | 2021-07-09 | 西安工程大学 | Super-hydrophobic surface resistance reduction performance testing device under high flow rate |
| CN113740030A (en) * | 2021-11-05 | 2021-12-03 | 水利部交通运输部国家能源局南京水利科学研究院 | Pipeline resistance parameter detection system and detection method |
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| SU544883A1 (en) * | 1975-11-28 | 1977-01-30 | Научно-исследовательский институт механики Московского государственного университета им.М.В.Ломоносова | Method for determining the coefficient of hydrodynamic resistance of the body during cavitation |
| CN2055195U (en) * | 1989-05-06 | 1990-03-28 | 吉林电力职工大学 | Experiment console for teaching and studying hydrodynamics and pump characteristic |
| CN2847268Y (en) * | 2005-11-29 | 2006-12-13 | 扬州大学 | Pipeline characteristic complex test instrument |
| CN200982915Y (en) * | 2006-08-25 | 2007-11-28 | 浙江天煌科技实业有限公司 | A hydrodynamic integrated experimental device |
| CN101777279B (en) * | 2010-01-28 | 2012-02-01 | 哈尔滨工程大学 | Water tank for regular wave generation research and teaching |
| CN202332036U (en) * | 2011-11-10 | 2012-07-11 | 浙江天煌科技实业有限公司 | Novel fluid mechanics comprehensive experiment device |
| CN202582871U (en) * | 2012-04-01 | 2012-12-05 | 西安理工大学 | Frictional resistance experiment instrument |
| CN104296962B (en) * | 2014-10-23 | 2017-06-30 | 东北石油大学 | Measure the viscosity factor and inertial resistance coefficient experimental provision of porous media |
| CN204576913U (en) * | 2015-02-06 | 2015-08-19 | 刘青 | A kind of Multifunction hydrodynamic calculations platform |
| CN204649347U (en) * | 2015-06-11 | 2015-09-16 | 洛阳理工学院 | A kind of novel local resistance coefficient determination experiment device |
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