The Study On Five-hole Probe In Airflow Velocity Measurement

Gas velocity is one of the important parameters of engineering practice and experimental research.Accurate measurement of velocity has great practical significance for industrial production and experiment.However,as a reliable and effective measurement tool,the five-hole probe is rarely used in the measurement of high-speed airflow and real gas velocity so far.This paper mainly investigates the use of five-hole probe in the measurement of gas velocity in detail,including the design and verification of the probe improvement of the accuracy of different gas measurement,etc.,and the application of five hole probe to carry out more kinds of fluids The velocity measurement broadens the research scope of five-hole probe in the practical application end.In this paper,the following work is completed through numerical simulation and experimental measurement:(1)Through numerical simulation,the front-end form,rod body and material of the five-hole probe are selected,and the optimal scheme is selected to complete the manufacturing of the five-hole probe.After comparing the results,a conical probe made of stainless steel is used for experimental measurement in this paper.We also completed the construction of electric motion system and pressure measurement and acquisition system for the control and movement of five-hole probe,pressure signal measurement and acquisition.(2)We have completed the measurement of ideal gas velocity of the five-hole probe by numerical simulation and experimental methods,and use the five-hole probe to conduct velocity measurement experiments on the flow field of subsonic and supersonic ideal gases.The measurement and simulation results show that the measurement error is within the acceptable range of engineering use,which proves that the five-hole probe verification method and the accuracy of the measurement use can meet the engineering use requirements.(3)According to the measurement and simulation results,it is found that the influence of air compressibility should be considered when measuring the air velocity above 0.3Ma,and the temperature sensor should be used to measure the air temperature,calculate the property parameters of the air flow,and correct the air velocity.Through the theoretical study,the compressibility of the air flow and the influence of shock wave on the flow field measurement are studied in detail,and the relevant theoretical formula is derived to modify the measurement results.(4)Through theoretical research,the calculation of real gas physical properties is deduced,and the program is made for the calculation of real gas physical properties.The derivation of the relationship between the parameters of real gas before and after the isentropic process and shock wave is also completed.The real gas velocity measurement is studied by numerical simulation.