COMPUTATIONAL STUDY OF HEAT TRANSFER CHARACTERISTICS OF SUPERCRITICAL METHANE FLOW IN THE COOLANT CHANNEL OF A ROCKET ENGINE

Liquid methane as a rocket fuel has promising prospects for deep space travel in the near future owing to its possible availability in alien planets. The major challenge however appears to be to properly address the issue of unusual heat transfer characteristics observed in the coolant channel at supercritical pressures, typically when the coolant fluid temperatures exceed a critical value. The current work systematically looks at the applicability of typical one-dimensional model to predict the heat transfer behavior in the coolant channel. The study then extends to a 2D numerical analysis and parametric investigation with an objective to study the effect of heat flux on heat transfer at a supercritical pressure. A 2D numerical analysis indicates that the one-dimensional approach is having limited applicability for heat transfer at a supercritical pressure. A systematic study has been carried out in the current work to investigate the onset of heat transfer deterioration in rocket engine coolant channels which involves asymmetric heating. The study indicates that heat transfer deterioration can be expected as the heat flux is increased and interestingly localized flow acceleration owing to sharp fall in density appears to have a prime influence on the heat transfer deterioration. An attempt has been made to look at some possible methods to offset the heat transfer deterioration, and the study reveals that providing higher surface roughness could be a simple possible means to overcome the heat transfer deterioration.