Pressure Effects on Hydrogen Peroxide Decomposition Temperature.

摘要

The use of very high concentration hydrogen peroxide (e.g., 98%) in rocket engines yields substantial specific impulse (Isp) gains when compared with traditional 90% peroxide engine systems. However, when used in pump-fed engines, 98% peroxide places a significant design burden on the turbine from a material strength and oxygen compatibility standpoint. The decomposition temperature for 98% peroxide is caret 1240 K (caret 2230 R), a temperature regime in which most alloys show a precipitous decline in strength. Thus, accurate prediction of gas generator catalytic bed outlet temperature is necessary for confident life and structural margin assessment. Analytical computations of maximum decomposition temperature at low pressures should be quite accurate using industry equilibrium chemistry codes such as the NASA/Lewis CEA computer program. Reported historical articles predict that caret 50 K (caret 90 R) increase in temperature due to real gas effects could be expected at pressures of 20.7 Mpa (3000 psi a) for 100% peroxide. A new analysis was performed to assess the validity of those estimates. The present calculations were made; (1) using recent water and oxygen real gas properties with two classical mixing rules, and (2) using two equation-of-state methods with associated mixing rules. The new results indicate a real gas temperature effect of caret 13 K (caret 23 R) at 20.7 Mpa (3000 psia). This smaller temperature increase should result in more manageable turbine design uncertainties.