基于传热反问题方法的N2O/C2H4预混推进剂燃烧室热流测量研究

Measurement of Heat Flux in a N2O/C2H4 Premixed Propellant Combustion Chamber Based on Inverse Heat Transfer Method

关键词:  液体火箭发动机  传热  传热反问题方法  热流  N₂O/C₂H₄预混推进剂

Key words:  Liquid rocket engine  Heat transfer  Inverse heat transfer method  Heat flux  N₂O/C₂H₄ premixed propellant

摘要:

测量液体火箭发动机的热载荷是获取燃烧室内部信息的重要方法。为了获取N₂O/C₂H₄预混推进剂燃烧室内壁的热载荷，建立了液体火箭发动机的热流计算的反问题方法，该方法基于对燃烧室壁面温度场的直接求解，通过对轴向多个位置测量温度的反演计算得到燃烧室内壁热流和温度。研究表明：应用文中建立的传热反问题方法能够较为准确地获得热流随时间及空间的分布；热电偶的位置对计算准确性有明显的影响，与理论深度偏差在0.2mm以内的随机深度偏差可导致超过4%热流反演误差；N₂O/C₂H₄预混推进剂燃烧室热流及温度沿轴向逐渐降低，表明燃烧室内的反应释热过程主要在燃烧室头部附近发生。

Abstract:

Measuring the thermal load of a liquid rocket engine is an important way for obtaining information inside the combustion chamber. In order to obtain the thermal load on the inner wall of a N₂O/C₂H₄ premixed propellant combustion chamber, an inverse method for heat flux calculation of liquid rocket engine is established. The inverse method is based on the direct solution of the temperature field of the combustion chamber wall. Through the inversion calculation of the axial measurement temperature, the heat flux and temperature of the inner wall of the combustion chamber are obtained. The conclusions of the research are as followed. The heat transfer inverse problem method established in the paper can accurately obtain the distribution of heat flux with time and space. The position of the thermocouples has a significant impact on the accuracy of the calculation. A random depth deviation from a theoretical depth of less than 0.2 mm can result in more than 4% inverse heat flux error. The heat flux and temperature of the N₂O/C₂H₄ premixed propellant combustion chamber gradually decrease along the axial position, indicating that the heat release mainly take place close to the head of the chamber.