A Computational Study on the Thrust Performance of a Supersonic Pintle Nozzle

نویسندگان

  • Ruoyu Deng
  • Toshiaki Setoguchi
چکیده

Typical solid rocket motors (SRM) have advantage of their inherent simplicity and reliability, but they do not have the capability to change thrust profile like other propulsion system. Pintle technology is one of the means to achieve variable and programmable thrust. This paper describes a study of the static and dynamic characteristics of a pintle nozzle under the constant mass flow rate. The mass flow rate is fixed in 1.744kg/sec and pintle stoke is adjusted in range from 0mm to 60mm . An analytical model has been created for comparison. A two-dimensional axisymmetric numerical simulation has been carried for thrust performance during the pintle moving process. To validate the ability of the numerical model, numerical results were compared with the analytical and experimental results. They show quite good match in different pintle strokes. Aiming to optimum dynamic performance, different pintle speeds should be researched. Chamber pressure goes up dramatically due to pintle movement. The pressure evolution is not unique in the process of the pintle movement but shows the delay effect. By adjusting the pintle speed, chamber pressure and thrust histories with time would be calculated based on CFD models. The dynamic characteristics of the pintle nozzle largely depend on the mass flow rate through the throat. It also depends on the pintle activation because mass flow rate through the throat varies with the pintle stroke in the dynamic process. The result will provide the reference to the further development. INTRODUCTION Solid rocket engines are used on air-to-air and air-toground missiles, on model rockets, and as boosters for satellite launchers. Solid rocket motor has dominated the tactical missile field owing to its inherent simplicity and reliability without significant design compromises. However, it is difficult to change the designed thrust profile with a conventional solid propellant motor because the solid propellant is continuously or unstoppably burned until all the propellant is consumed after ignition. Pintle technology, to achieve the variable thrust for the mission, is basically similar to that of the flow control employed for the globe valve, of which the cross-sectional area of the flow passage is changed by the pintle. Detailed flow features concerned with pintle section play the key role in thrust manage system. Many studies were carried out in the last four decades to research the pintle technology. Pintle technology used in escape system of military aircraft was searched, this system provided fully controllable propulsion to suit the circumstances of each emergency, see Rock et al.(1997). Dual-thrust technology was to control the burning surface of the solid propellant by designing the grain shape, and pulse motor technology divides solid propellant into two or three sections using an insulation technique. It was developed to increase mission range and end-game maneuverability, see Harold et al. (1996). The effects of several important parameters were studied in pintle technology, the important relationship between pintle geometry, pintle position and throat area can be determined and used for design decisions, see Ostrander et al. (2000). Various pintle nozzle exit cone contours were investigated using analytical model, it provided the optimizing pintle nozzle contour which produces the highest specific impulse, see Randall et al. (1995). Steady and unsteady characteristics of a pintle conical nozzle were studied numerically based on SpalartAllmaras one equation turbulence model. Also, performance variations were examined in terms of the pintle speed and pintle geometies, see Lee et al. (2013). Although many researches on developing optimal strategies of pintle nozzle were done during past years, there was few numerical study based on two-equations turbulent model. A computational fluid dynamics (CFD)-based study has been conducted for studying the steady and unsteady phenomenon. The purpose of the present study has been to 1 June 30 July 3, 2015 Melbourne, Australia 9 P-10

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تاریخ انتشار 2015