Dynamic response characteristics of vacuum pressure measurement system with pneumatic long-thin tube

The pneumatic long-thin tube between a measured pressure source and pressure sensor is a key component of a vacuum pressure measurement system (VPMS). The dynamic response characteristics of a pneumatic long-thin tube significantly affects the accuracy of the VPMS. This paper presents a mathematical model of the pressure propagation in a VPMS. The mathematical model accounts for the effects of fluid viscosity and heat transfer. A method for testing dynamic response characteristics of the VPMS is proposed. The sinusoidal vacuum pressure signal source was generated by a device consisting of a closed chamber and a loudspeaker. A series of tests were carried out using pneumatic long-thin tube with diameters of 2 and 3 mm, lengths of 100 and 300 mm, and initial vacuum pressures of 3.3 and 30 kPa. The comparison of the experimental and mathematical simulation results demonstrated that the mathematical model could accurately describe the dynamic response characteristics of the VPMS within certain frequency and pressure ranges. The results of this paper have general implications for the design and analysis of the VPMSs. •A method for testing frequency response characteristics of a VPMS, generating dynamic vacuum pressure signal source by the closed chamber and the loudspeaker, was proposed.•The input pressure amplitude was not always attenuated and could be amplified when the frequency was near the system resonance frequency.•The amplitude ratio and phase lag all decreased with the increase of vacuum pressure and tube diameter.•The theoretical and experimental error of phase lag did not exceed 1% with the diameter of 3 mm and the length of 100 mm.