Study on the Effects of Structural Parameters of the Pre-Cooler on the Performance of Combined Power Generation Engines

The pre-cooler is a key component of the pre-cooled turbine combined cycle engine, and its performance significantly impacts the overall engine performance. To clarify the flow and heat transfer characteristics of the pre-cooler and the effects of its key structural parameters on engine performance, the pre-cooler of the SABRE engine (Synergetic Air-Breathing Rocket Engine) was analyzed using numerical simulation methods to investigate the influences of air crossflow tube bundles and tube spacing on pre-cooler performance. The results indicate that increasing the number of air crossflow tubes significantly enhances heat transfer capacity; however, it also leads to an increase in the total pressure drop. Specifically, as the number of air crossflow tubes increases from 24 to 48, the overall heat transfer capacity improves by 42.1%, while the total pressure loss coefficient nearly doubles. Additionally, increasing tube spacing reduces the overall pressure drop, but this comes at the cost of decreasing heat transfer capacity and structural compactness. When the total pressure loss coefficient was reduced by approximately 29.8%, the overall heat transfer capacity decreased by 4.9%. Notably, the impact of tube spacing on flow resistance is greater than its effect on heat transfer, suggesting that the total pressure loss can be minimized by optimizing tube spacing. Therefore, both performance and structural integrity must be considered in pre-cooler design. Finally, selecting appropriate structural parameters based on operating conditions is essential to optimize heat transfer efficiency and overall design quality.