Wall heat transfer measurements in high-pressure combustion devices

To investigate the wall heat transfer characteristics in a combustion chamber over a broad range of pressure conditions, a method of taking a series of wall temperature measurements in a heat sink combustion chamber, and calculating the wall temperature and heat flux from the temperature data, was introduced. The temperature and heat flux at the inner wall of the combustion chamber can be obtained using this method. The key parameters of the test article are presented, and the technique requirements for thermocouples are described. A two-dimensional (2D) axisymmetric numerical calculation method was developed to obtain the wall temperature and heat flux from the measured temperatures. The method was applied to a firing test of a single-element gaseous hydrogen/gaseous oxygen shear-coaxial injector chamber to demonstrate the details of the method. Furthermore, the heat transfer characteristics of a single-element combustion chamber at chamber pressures of 0.92 MPa to 6.1 MPa were investigated using this method. The results indicate that the wall heat flux of this gas-gas injector combustor has, qualitatively, the same distribution at different pressures and correlates quantitatively with the chamber pressure as q̇∼pc0.8.