Overheating Anomalies during Flight Test Due to the Base Bleeding
In this paper we present the results of the analytical and numerical studies of the plume interaction with the base flow in the presence of base out-gassing. The physics-based analysis and CFD modeling of the base heating for single solid rocket motor performed in this research addressed the following questions: what are the key factors making base flow so different from that in the Shuttle [1]; why CFD analysis of this problem reveals small plume recirculation; what major factors influence base temperature; and why overheating was initiated at a given time in the flight. To answer these questions topological analysis of the base flow was performed and Korst theory was used to estimate relative contributions of radiation, plume recirculation, and chemically reactive out-gassing to the base heating. It was shown that base bleeding and small base volume are the key factors contributing to the overheating, while plume recirculation is effectively suppressed by asymmetric configuration of the flow formed earlier in the flight. These findings are further verified using CFD simulations that include multi-species gas environment both in the plume and in the base. Solid particles in the exhaust plume (Al2O3) and char particles in the base bleeding were also included into the simulations and their relative contributions into the base temperature rise were estimated. The results of simulations are in good agreement with the temperature and pressure in the base measured during the test.
A study on prediction of the base pressures for an axi-symmetric body
A flow modeling method has been developed to analyze the flow in the annular base (rear-facing surface) of a circular engine nacelle flying at subsonic speed but with a supersonic exhaust jet. Real values of exhaust gas properties and temperature at an altitude of 30,000 feet are employed. Potential flows of the air and gas streams are computed for the flow past a separated wake. Then a viscous jet mixing is superimposed on this inviscid solution. Conservation of mass, momentum and energy for the wake flow field is achieved by multiple iterations with modest computer requirements.
Trends in kiln drives
The heart of the cement plant is the rotary kiln, and continuous quality production of cement clinker depends on the continuous accurate performance of the rotary kiln drive.