Ground Test Investigation of Temperature Distribution in Four Parallel High-Altitude Engines

This paper describes a ground test investigation of temperature distribution in the vacuum cabin of an engine group with four parallel nozzles when subjected to the high-altitude conditions encountered in space. A new scheme was devised to simulate and evaluate the influence of radiative heat transfer on the wall temperature distribution of high-altitude engines in the vacuum cabin. Nozzles used in the ground test were geometrically and physically analogous to the actual ones used in space. Electric heating nozzles, instead of the actual ones, were used in the test unit. Characteristics of the wall temperature distribution were obtained by measuring the wall temperatures of the four- and two-parallel-nozzle configurations. It was shown from the testing data that, due to the mutual radiation among high-temperature nozzles with small gaps, the maximum circumferential temperature rise, Delta T(max) was less than 30K at the throat with high temperature, whereas Delta T(max) was less than 250K at the exit with low temperature. Thus, the temperature rise of the whole thrust chamber did not affect the normal working of the set of engines. Comparing the data from numerical simulation, it is indicated that the results from the electric heating test in a vacuum cabin are conservative and reliable.