CN115078168A - Method for measuring oil film volatilization on surface of reciprocating seal piston rod - Google Patents
Method for measuring oil film volatilization on surface of reciprocating seal piston rod Download PDFInfo
- Publication number
- CN115078168A CN115078168A CN202210472260.3A CN202210472260A CN115078168A CN 115078168 A CN115078168 A CN 115078168A CN 202210472260 A CN202210472260 A CN 202210472260A CN 115078168 A CN115078168 A CN 115078168A
- Authority
- CN
- China
- Prior art keywords
- oil
- piston rod
- volatilization
- oil film
- reciprocating
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000009792 diffusion process Methods 0.000 claims abstract description 30
- 230000033001 locomotion Effects 0.000 claims abstract description 24
- 230000004907 flux Effects 0.000 claims abstract description 15
- 238000007789 sealing Methods 0.000 claims description 12
- 229920006395 saturated elastomer Polymers 0.000 claims description 8
- 101100161290 Mus musculus Nt5c1b gene Proteins 0.000 claims 1
- 239000003921 oil Substances 0.000 description 69
- 239000003350 kerosene Substances 0.000 description 12
- 239000007788 liquid Substances 0.000 description 8
- 239000000295 fuel oil Substances 0.000 description 4
- 230000008020 evaporation Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 239000010720 hydraulic oil Substances 0.000 description 3
- 230000003068 static effect Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 239000000693 micelle Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/26—Oils; Viscous liquids; Paints; Inks
- G01N33/28—Oils, i.e. hydrocarbon liquids
- G01N33/2829—Mixtures of fuels
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Immunology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Examining Or Testing Airtightness (AREA)
Abstract
The invention relates to a method for measuring the oil film volatilization on the surface of a reciprocating seal piston rod, which comprises the following steps: step 1) acquiring working conditions and a piston rod motion state; step 2) determining the pressure of oil vapor components and the normal distance from a boundary to an oil film on the surface of the piston rod under the vapor pressure of a preset proportion based on the working condition; step 3) calculating the diffusion coefficient of the oil-air system based on the working condition and the diffusion volumes of the oil and the air; step 4), calculating mass transfer flux based on the diffusion coefficient of the oil-air system, the pressure of oil vapor components and the normal distance; and 5) calculating the oil volatilization volume in one motion period based on the mass transfer flux. Compared with the prior art, the method has the advantages of reasonably simplifying the calculation process, being accurate in calculation result and the like.
Description
Technical Field
The invention relates to the field of hydraulic transmission sealing, in particular to a method for measuring the volatilization of an oil film on the surface of a reciprocating sealing piston rod.
Background
Liquid evaporation is a mass transfer process. Substances can be transferred in-phase or inter-phase due to concentration differences. Molecular diffusion and convective diffusion are two basic forms of mass transfer. The molecular diffusion mass transfer refers to mass exchange generated by intermolecular mutual diffusion, and is based on the free thermal motion of microscopic molecules and mass exchange along the direction of concentration gradient; convective diffusive mass transfer is mass exchange based on the macroscopic motion of particles or micelles.
In the calculation of the reciprocating seal leakage amount by taking hydraulic oil as a working medium, the volatilization amount of an oil film on the surface of the piston rod is small, and the calculation result of the leakage amount is not influenced enough. However, the common fuel oil in the hydraulic system of the aircraft engine replaces the traditional hydraulic oil to be used as a transmission medium, the fuel oil is volatile in a high-temperature environment, the influence of the volatilization amount of the fuel oil on the actual leakage amount cannot be ignored, and the measurement method of the volatilization amount of the oil film does not exist at present.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide the measuring method for the oil film volatilization on the surface of the reciprocating sealing piston rod, which has accurate calculation result and simple and convenient calculation process.
The purpose of the invention can be realized by the following technical scheme:
a method for measuring the oil film volatilization on the surface of a reciprocating seal piston rod comprises the following steps:
step 1) acquiring working conditions and a piston rod motion state;
step 2) determining the pressure of oil vapor components and the normal distance from a boundary to an oil film on the surface of the piston rod under the vapor pressure of a preset proportion based on the working condition;
step 3) calculating the diffusion coefficient of the oil-air system based on the working condition and the diffusion volumes of the oil and the air;
step 4), calculating mass transfer flux based on the diffusion coefficient of the oil-air system, the pressure of oil vapor components and the normal distance;
and 5) calculating the oil volatilization volume in one motion period based on the mass transfer flux.
The working conditions of the step 1) comprise oil temperature, ambient temperature and ambient pressure.
The motion state of the piston rod in the step 1) comprises the diameter of the piston rod, the stroke length of the piston rod and the reciprocating motion speed of the piston rod.
And 2) determining the pressure and the normal distance of the oil vapor component according to experimental data or empirical values.
The diffusion coefficient D of the oil-air system in the step 3) oa The calculation formula is as follows:
wherein, T a Is ambient temperature, M o Is the molar mass of the oil, M a Is the molar mass of air, P is the ambient pressure, v o Is the diffusion volume of oil, v a Is the diffusion volume of air.
The mass transfer flux N in the step 4) A The calculation formula is as follows:
wherein, the position A is the position of the oil film on the surface of the piston rod, the position B is a boundary set according to an empirical value, y _A And y _B Normal position coordinates, y, for position A and position B, respectively _B -y _A For the normal distance, p, determined in step 2) a_A And p a_B Is the non-oil vapor component pressure, P, at positions A and B a Is at standard atmospheric pressure, P o Is the saturated vapor pressure of the oil, D oa Is the diffusion coefficient, T, of the oil-air system o The temperature of the oil is adopted, and R is an ideal gas constant.
And 5) dividing the oil film volatilization process into different time periods according to whether the reciprocating operation speed of the piston rod is zero, respectively calculating the volatilization amount, wherein the volatilization amount of the oil liquid in one motion period is the sum of the volatilization amounts of the oil liquid in each time period:
wherein, Δ m is the volatilization volume of the oil in one motion period, and Δ m i For the oil in each time periodThe amount of liquid volatilized.
The oil volatilization amount Delta m in each time period i The calculation formula is as follows:
wherein N is A For mass transfer flux, M o Is the molar mass of the oil, A is the effective volatilization area of the oil film, t i Is the corresponding time period duration.
The effective volatilization area A of the oil film depends on whether the reciprocating running speed of the piston rod is zero, and when the reciprocating running speed of the piston rod is zero, the effective volatilization area A of the oil film is as follows:
A＝πdL
wherein d is the diameter of the piston rod, and L is the stroke length of the piston rod in the corresponding time period;
when the reciprocating running speed of the piston rod is not zero, the effective volatilization area A of the oil film is as follows:
A＝πdvt
wherein d is the diameter of the piston rod, v is the reciprocating running speed of the piston rod, and t is the duration of the corresponding time period.
The oil liquid is a high-volatility medium and comprises fuel oil and aviation No. 10 hydraulic oil.
Compared with the prior art, the invention has the following beneficial effects:
(1) through reasonable assumption and analysis, the invention simplifies the complex mass transfer quantity calculation process of the oil film under the reciprocating motion, is convenient for measuring and calculating the volatile quantity of the oil, has simple and convenient calculation process, reduces the calculation quantity and improves the calculation efficiency.
(2) According to the method, the oil volatilization amount is used for correcting the measurement result of the external leakage amount of the seal, the measurement accuracy of the external leakage amount of the seal pair is improved, and the gap of the measurement method of the oil film volatilization amount on the surface of the reciprocating seal piston rod in the sealing field is filled.
Drawings
FIG. 1 is a schematic illustration of a piston rod ejection process of the present invention;
FIG. 2 is a schematic illustration of a convective mass transfer process of the present invention;
FIG. 3 is a schematic view of an embodiment of the present invention illustrating a state of motion of an aero-actuator;
FIG. 4 is a piston rod static mass transfer model in an embodiment of the present invention;
FIG. 5 is a graph of the diffusion coefficient of an oil-air system as a function of ambient temperature in an embodiment of the present invention;
FIG. 6 is a graph of mass transfer flux as a function of oil temperature in an embodiment of the present invention;
FIG. 7 is a graph showing the volatilization amount of oil according to the temperature of oil in the embodiment of the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Taking a certain type of aviation actuator as an example, the method for measuring the oil film volatilization amount on the surface of the reciprocating sealing piston rod comprises the following steps:
step 1) obtaining working conditions and motion states of piston rods
The schematic diagram of the motion state of the aero-actuator is shown in figure 3,
the working conditions are as follows: the working medium is RP-3 aviation kerosene; the temperature of the oil liquid is-40 ℃ to 140 ℃; the ambient temperature is-55 ℃ to 215 ℃; the ambient pressure is standard atmospheric pressure.
The motion state of the piston rod is as follows: the reciprocating speed is 0.05m/s, and the corresponding stroke duration is as follows: 0.8s outer stroke, 0.2s stop, 0.8s inner stroke, 0.2s stop; the diameter d of the piston rod is 21mm and the working stroke L is 40 mm.
Step 2) determining the component pressure of oil vapor and the normal distance from the boundary to the oil film on the surface of the piston rod under the steam pressure of a preset proportion based on the working condition
FIG. 4 is a piston rod static steady-state mass transfer model, wherein the position A is an oil film surface, the partial pressure of kerosene at the position B which is 0.01m away from the oil film is approximately 0.5 saturated vapor pressure measured by tests at 22 ℃ and standard atmospheric pressure, and the normal distance between the position A and the position B is 0.01 m.
Since the mass transfer of the oil film from the A position to the B position is in a static state, the sum of the air pressures of all points between the AB is the saturated vapor pressure at the current temperature, and the components of the oil film in the embodiment are mainly air and kerosene. The oil film surface is at A, where the kerosene partial pressure is the saturated vapor pressure P of kerosene rp3 Partial pressure of air of p a_A ＝P a -P rp3 (ii) a The partial pressure of kerosene at B is 0.5 times the saturated vapor pressure of kerosene, i.e. 0.5P rp3 Partial pressure of air of p a_B ＝P a -0.5P rp3 。
Step 3) calculating the diffusion coefficient of the oil-air system based on the working condition and the diffusion volume of the oil and the air
Wherein D is rp3-air Is the diffusion coefficient of the oil-air system, M rp3 Is the molar mass of kerosene, and is 153.62 g/mol; m air Air molar mass is 29 g/mol; v. of rp3 Is the diffusion volume of kerosene, v rp3 ＝209.82ml/mol，v air Volume of air diffusion, v air ＝19.7ml/mol。
By substituting the environmental temperature interval given by the working condition, the change curve of the diffusion coefficient of the oil-air system along with the environmental temperature in the embodiment can be obtained, as shown in fig. 5.
Step 4) calculating mass transfer flux based on the diffusion coefficient of the oil-air system, the pressure of oil vapor components and the normal distance
Wherein, P a Is a standard atmospheric pressure; p rp3 Is the saturated vapor pressure of RP-3 aviation kerosene, the saturated vapor pressure of the famous RP-3 aviation kerosene is selected, D rp3-air Is the diffusion coefficient, T, of the oil-air system o Is the oil temperature, y _ And y _ By position A and position B, respectivelyPosition coordinate, (y) _ -y _ ) The normal distance, p, determined in step 2) a_A And p a_B For the non-oil vapor component pressure, p, at positions A and B determined in step 2) a_A ＝P a -P rp3 ，p a_B ＝P a -0.5P rp3 And R is an ideal gas constant.
Thus, a mass transfer flux curve with the oil temperature can be obtained through the oil temperature interval, as shown in fig. 6.
Step 5) calculating the oil volatilization amount delta m in one motion period based on the mass transfer flux rp3
Dividing the oil film volatilization process into different time periods according to whether the reciprocating operation speed of the piston rod is zero, respectively calculating the volatilization amount, wherein the volatilization amount of the oil liquid in one motion period is the sum of the volatilization amounts of the oil liquid in each time period:
wherein, Δ m rp3 Is the oil volatilization volume in one movement period, Delta m i_rp3 The oil volatilization amount in each time period is adopted.
The oil volatilization amount Delta m in each time period i_rp3 The calculation formula is as follows:
wherein N is A_rp3-air Mass transfer flux, M, of the oil-air system obtained in step 4) rp3 Is the molar mass of RP-3 kerosene, A is the effective volatilization area of the oil film, t i Is the corresponding time period duration.
The effective volatilization area A of the oil film depends on whether the reciprocating running speed of the piston rod is zero, and when the reciprocating running speed of the piston rod is zero, the effective volatilization area A of the oil film is as follows:
A＝πdL
wherein d is the diameter of the piston rod, and L is the stroke length of the piston rod in the corresponding time period;
when the reciprocating running speed of the piston rod is not zero, the effective volatilization area A of the oil film is as follows:
A＝πdvt
wherein d is the diameter of the piston rod, v is the reciprocating running speed of the piston rod, and t is the duration of the corresponding time period.
According to steps 1) and 2), the oil film evaporation process can be divided into three time periods, the first time period (Δ t) 1 ) The reciprocating operation speed of the piston rod is not zero, the reciprocating operation speed comprises two processes of extending and retracting the piston rod, as shown in (i) and (ii) in fig. 3, the process is 1.6s in total, and the effective volatilization area is the area (pi dL/2) of the fully extended rod; the second time interval (delta t) 2 ) The reciprocating operation speed of the piston rod is zero, the process of extending and standing is included for 0.2s, and as shown in the second step in figure 3, the effective volatilization area is the area (pi dL) of the fully extended rod; the third time interval (Δ t) 3 ) The reciprocating speed of the piston rod is zero, including 0.2s of retraction and rest process, as shown in the third part of figure 3, at this time, the oil-free film is exposed to the air, so that no statically stable volatilization exists. The oil film evaporation amount in the three time periods is calculated as follows:
Δm 2_rp3 ＝N A_rp3-air M rp3 πdLΔt 2
Δm 3_rp3 ＝0
oil volatilization delta m of one complete motion period rp3 Comprises the following steps:
Δm rp3 ＝Δm 1_rp3 +Δm 2_rp3 +Δm 3_rp3
the curve of the variation of the oil volatilization amount with the oil temperature in this example is shown in fig. 7.
Claims (10)
1. A method for measuring the oil film volatilization on the surface of a reciprocating seal piston rod is characterized by comprising the following steps:
step 1) acquiring working conditions and a piston rod motion state;
step 2) determining the pressure of oil vapor components and the normal distance from a boundary to an oil film on the surface of the piston rod under the vapor pressure of a preset proportion based on the working condition;
step 3) calculating the diffusion coefficient of the oil-air system based on the working condition and the diffusion volumes of the oil and the air;
step 4), calculating mass transfer flux based on the diffusion coefficient of the oil-air system, the pressure of oil vapor components and the normal distance;
and 5) calculating the oil volatilization volume in one motion period based on the mass transfer flux.
2. The method for measuring the oil film volatilization amount on the surface of the reciprocating sealing piston rod according to claim 1, wherein the working conditions in the step 1) comprise oil temperature, ambient temperature and ambient pressure.
3. The method for measuring the oil film volatilization on the surface of the reciprocating sealing piston rod as claimed in claim 1, wherein the motion state of the piston rod in the step 1) comprises the diameter of the piston rod, the stroke length of the piston rod and the reciprocating running speed of the piston rod.
4. The method for measuring the oil film volatilization amount on the surface of the reciprocating sealing piston rod according to claim 1, wherein the oil vapor component pressure and the normal distance in the step 2) are determined according to experimental data or empirical values.
5. The method for measuring the oil film volatilization on the surface of the reciprocating sealing piston rod as claimed in claim 1, wherein the step 3) is carried out by using an oil-air system diffusion coefficient D oa The calculation formula is as follows:
wherein, T a Is ambient temperature, M o Is the molar mass of the oil, M a Is the molar mass of airP is the ambient pressure, v o Is the diffusion volume of oil, v a Is the diffusion volume of air.
6. The method for measuring the oil film volatilization amount of the surface of the reciprocating sealing piston rod as claimed in claim 1, wherein the mass transfer flux N in the step 4) is A The calculation formula is as follows:
wherein, the position A is the position of the oil film on the surface of the piston rod, the position B is a boundary set according to an empirical value, y _A And y _B Normal position coordinates, y, for position A and position B, respectively _B -y _A For the normal distance, p, determined in step 2) a_A And p a_B Is the non-oil vapor component pressure, P, at positions A and B a Is at standard atmospheric pressure, P o Is the saturated vapor pressure of the oil, D oa Is the diffusion coefficient, T, of the oil-air system o The temperature of the oil is adopted, and R is an ideal gas constant.
7. The method for measuring the oil film volatilization amount on the surface of the reciprocating seal piston rod according to claim 1, wherein in the step 5), the oil film volatilization process is divided into different time periods according to whether the reciprocating running speed of the piston rod is zero, the volatilization amounts are respectively calculated, and the oil volatilization amount in one motion cycle is the sum of the oil volatilization amounts in all the time periods:
wherein, Δ m is the volatilization volume of the oil in one motion period, and Δ m i The oil volatilization amount in each time period is adopted.
8. The method of claim 7 wherein the amount of oil film evaporated from the surface of the reciprocating piston rodIs characterized in that the oil volatilization quantity Deltam in each time period i The calculation formula is as follows:
wherein N is A For mass transfer flux, M o Is the molar mass of the oil, A is the effective volatilization area of the oil film, t i Is the corresponding time period duration.
9. The method for measuring the oil film volatilization amount on the surface of the reciprocating sealing piston rod as claimed in claim 8, wherein the effective oil film volatilization area A depends on whether the reciprocating running speed of the piston rod is zero, and when the reciprocating running speed of the piston rod is zero, the effective oil film volatilization area A is as follows:
A＝πdL
wherein d is the diameter of the piston rod, and L is the stroke length of the piston rod in the corresponding time period;
when the reciprocating running speed of the piston rod is not zero, the effective volatilization area A of the oil film is as follows:
A＝πdvt
wherein d is the diameter of the piston rod, v is the reciprocating running speed of the piston rod, and t is the duration of the corresponding time period.
10. The method for measuring the oil film volatilization amount of the surface of the reciprocating sealing piston rod as claimed in claim 1, wherein the oil is a high-volatility medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210472260.3A CN115078168A (en) | 2022-04-29 | 2022-04-29 | Method for measuring oil film volatilization on surface of reciprocating seal piston rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210472260.3A CN115078168A (en) | 2022-04-29 | 2022-04-29 | Method for measuring oil film volatilization on surface of reciprocating seal piston rod |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115078168A true CN115078168A (en) | 2022-09-20 |
Family
ID=83246845
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210472260.3A Pending CN115078168A (en) | 2022-04-29 | 2022-04-29 | Method for measuring oil film volatilization on surface of reciprocating seal piston rod |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115078168A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08200150A (en) * | 1995-01-20 | 1996-08-06 | Toyota Motor Corp | Piston for internal combustion engine |
| CN103939330A (en) * | 2014-04-29 | 2014-07-23 | 同济大学 | Damping noise reduction valve plate for plunger hydraulic pump |
| CN113530789A (en) * | 2021-08-18 | 2021-10-22 | 优捷特清洁能源有限公司 | Oil mist isolation structure of liquid-driven compressor |
-
2022
- 2022-04-29 CN CN202210472260.3A patent/CN115078168A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08200150A (en) * | 1995-01-20 | 1996-08-06 | Toyota Motor Corp | Piston for internal combustion engine |
| CN103939330A (en) * | 2014-04-29 | 2014-07-23 | 同济大学 | Damping noise reduction valve plate for plunger hydraulic pump |
| CN113530789A (en) * | 2021-08-18 | 2021-10-22 | 优捷特清洁能源有限公司 | Oil mist isolation structure of liquid-driven compressor |
Non-Patent Citations (2)
| Title |
|---|
| YIN YAOBAO等: "Temperature Characteristics of PP of Axial Piston Pump", CHINA MECHANICAL ENGINEERING, vol. 26, no. 8, 24 March 2016 (2016-03-24), pages 1073 - 1077 * |
| 李晶等: "轴向柱塞泵柱塞副偏心状态油膜特性分析", 华南理工大学学报(自然科学版), vol. 44, no. 10, 31 October 2016 (2016-10-31), pages 30 - 35 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109297509A (en) | A kind of laser gyro bias drift error modeling and compensation method based on tri-state theory | |
| CN104697701A (en) | Piezoresistive pressure sensor | |
| CN108691585A (en) | A kind of computational methods of condensing turbine low pressure (LP) cylinder efficiency | |
| CN102589820B (en) | System and method for calibrating lower limit of positive-pressure leak by extending constant volume method | |
| CN104236817A (en) | Dynamic sealing performance testing method and device for plunger cylinder sleeve | |
| CN115078168A (en) | Method for measuring oil film volatilization on surface of reciprocating seal piston rod | |
| CN201666840U (en) | Sealing performance detector of sealing element | |
| JP2013204454A (en) | Calculation method of mass flow rate of external egr gas, calculation device for mass flow rate of external egr gas, and engine | |
| CN102426079A (en) | Simulation system and method for leakage detection of space station by using direction gauge | |
| CN114623979A (en) | Constant-volume positive-pressure leak hole calibration device and test method thereof | |
| Singh et al. | Investigation the Effect on Coefficient of filled and unfilled port to port dimension with plaster of paris of 2-Holes offset probe | |
| CN102798502A (en) | Method for acquiring air leakage of steam turbine shaft seal system | |
| CN101598586B (en) | MEMS technology based micro liquid level metering device and method thereof | |
| Song | Test study of the water quantity loss of cooling tower on U-type liquidometer | |
| CN220602609U (en) | Flow detection assembly suitable for remote or unmanned calibration | |
| Mai et al. | Impact of measurement uncertainty in the characteristic maps of a turbocharger on engine performance | |
| Benson et al. | Paper 34: Effects of Variable Specific Heats and Gas Composition on Unsteady Flow Calculations | |
| CN208588753U (en) | A kind of extension type cigarette air duct speed measuring device | |
| CN203148482U (en) | Gas flow measuring device suitable for being used on workshop conditions | |
| Elizondo | High-Speed Pressure-Sensitive Paint Measurements of a Hypersonic Vehicle | |
| Zahdeh | Diesel engine startability and white smoke formation under cold temperature conditions | |
| CN116502469B (en) | Turbine blade temperature correction method and device based on temperature test data | |
| CN201787991U (en) | Micro liquid volume metering device based on micro electro mechanism system (MEMS) technique | |
| Kong et al. | An Estimation Method for Scramjet Inlet Mach Number and Mass Flow Rate Based on Deep Learning | |
| Durham | Supersonic flow with variable specific heat |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |