Trade-off analysis of high-aspect-ratio-cooling-channels for rocket engines

• Aspect ratio has a significant effect on cooling efficiency and hydraulic losses.
• Minimizing power loss is of paramount importance in liquid rocket engine cooling.
• A suitable quasi-2D model is used to get fast cooling system analysis.
• Trade-off with assigned weight, temperature, and channel height or wall thickness.
• Aspect ratio is found that minimizes power loss in the cooling circuit.

High performance liquid rocket engines are often characterized by rectangular cooling channels with high aspect ratio (channel height-to-width ratio) because of their proven superior cooling efficiency with respect to a conventional design. However, the identification of the optimum aspect ratio is not a trivial task. In the present study a trade-off analysis is performed on a cooling channel system that can be of interest for rocket engines. This analysis requires multiple cooling channel flow calculations and thus cannot be efficiently performed by CFD solvers. Therefore, a proper numerical approach, referred to as quasi-2D model, is used to have fast and accurate predictions of cooling system properties. This approach relies on its capability of describing the thermal stratification that occurs in the coolant and in the wall structure, as well as the coolant warming and pressure drop along the channel length. Validation of the model is carried out by comparison with solutions obtained with a validated CFD solver. Results of the analysis show the existence of an optimum channel aspect ratio that minimizes the requested pump power needed to overcome losses in the cooling circuit.