喷管碳基喉衬的烧蚀

EROSION EVALUATION OF NOZZLE THROAT INSERTS

一、计算方法和结果 喷管材料的烧蚀主要是热和化学作用的结果。热量来自碳与燃气中的氧化元素之间的异相化学反应,以及对流和幅射传热。本文中的解析模型用来预测喷管温度分布及烧蚀率。在处理联结核心流及喷管壁面的边界层流动时,把传热传质数值作为壁内导热计算的输入数据。边界层的边界条件是由一维无粘定常流的解来确定的。在材料响应的分析中介入了幅射边界条件,在UTC数据上引入了一个有效辐射系数。用有限元计算方法求解瞬态热传导方程来确定喷管壁内温度分布随时间的变化关系。

A study has been conducted to evaluate the temperature distribution and recession behavior of graphite nozzles in rocket motors by solving two-dimensional transient heat transfer equations. Flowfield analysis takes in account the effects of A12O3 concentration through the contribution of particles on the stream density and temperature. The analytical model assumes that there is radiant exchange between the gas stream and the wall. An effective emissivity is used in this parallel plate radiation model. The results calculated in radiation and non-radiation conditions are compared for aluminized propellants, and also checked with data of Keswani and Kuo. The laboratory motor tests with double base propellants have been performed for verification of the analytical model. The temperature profiles in the nozzle have Been measured at four locations with Cr-Ni/Ni-Si sheathed thermocouples. The present model is in general agreement with the available experimental data