Instability characters and suppression method of a pressure regulator
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TECHNICAL PAPER
Instability characters and suppression method of a pressure regulator Jianguo Tan • Yanping Jiang • Zhenguo Wang
Received: 12 March 2012 / Accepted: 4 August 2012 / Published online: 14 March 2013 The Brazilian Society of Mechanical Sciences and Engineering 2013
Abstract With the increasing interest in hypersonic propulsion, National University of Defense Technology in China sets up a large high-temperature wind tunnel. A pilot-operated pressure regulator is developed to supply gas with a given pressure to the wind tunnel. Although the regulator works normally and stably during the working stage, severe oscillations with maximum amplitude of 3 MPa occur during the pressurization stage. To solve the problem, a numerical approach is developed to model the supply system, especially the pressure regulator. The approach is validated by comparing numerical results with experimental results. It turns out that the frequency of the oscillation is mainly determined by the inlet pipe, while the amplitude is affected by the downstream volume, the seal chamber and the seal orifice. To suppress the instability, a connecting pipe is adopted to let the gas in the seal chamber come from outside of the regulator. The method is quite simple but the effect is dramatic, as is attested feasible by both simulations and experiments. Keywords Pressure regulator Instability Suppression method Simulation
Technical Editor: Luı´s Fernando Silva. J. Tan (&) Y. Jiang Z. Wang Science and Technology on Scramjet Laboratory, National University of Defense Technology, Changsha 410073, Hunan, China e-mail: [email protected] Y. Jiang e-mail: [email protected] Z. Wang e-mail: [email protected]
List a A C d e f F h k K m_ M p R s t T V u
of symbols Sound speed, m/s Area, m2 Friction coefficient, null Diameter, m Specific internal energy, J/kg Oscillation frequency, Hz Force, N Specific enthalpy (J/kg) Ratio of specific heat, null Stiffness, Pa Mass flow rate, kg/s Mass, kg Pressure, Pa Gas constant, J/kg/K Displacement of plug, m Time, s Temperature, K Volume of chamber, m3 Velocity of gas, m/s
Greek symbols l Discharge coefficient q Density, kg/m3 k Darcy friction factor Subscripts in Inlet or upstream out Outlet or downstream
1 Introduction The worldwide interest in hypersonic vehicles has existed for a number of years [1]. The successful flight test of X-43A in 2004 was regarded as the third milestone of
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aviation since Wright’s glider in 1902. The flight test vehicle X-51A demonstrated a 140 s flight in 2010 using hydrocarbon fuel [2], leading to a practical application of hypersonic technology. One of the main obstacles to carry out hypersonic research is the difficulty of developing a high-temperature wind tunnel, which operates at high pressure and large flow rate. For example, at the end of 1980s, NASA Langley research center modified its 8-foot high-temperature tunnel for hypersonic experiments [3]. The air flow rate is 540 kg/s, supplied by air vessels with volume of 1,000 m3 and pressure of 40
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