Novel model for heat transfer and flow correlations of precooler, preheater and regenerator in supercritical CO2 Brayton cycle

Existing studies have not comprehensively incorporated actual operating conditions of precooler, low-temperature regenerator (LTR) and high-temperature regenerator (HTR) in S-CO₂ Brayton cycle. Additionally, while progress has been made, developing tailored correlations for specific conditions remains an area requiring further exploration. The novelty of this work lies in the combined experimental and numerical approach that provides insights into the heat transfer and flow behavior across a wide range of actual operating conditions. The findings demonstrate that heat transfer coefficient in precooler and regenerator decreases and increases as inlet pressure rises, respectively. Notably, average heat transfer coefficient on cold side of the LTR is approximately three times that on hot side of the LTR at same Reynolds number. After incorporating wall temperature as a factor in our considerations, the heat transfer correlation are developed for the precooler that yields a prediction accuracy of 99.5 % for numerical data, with an error margin controlled within ±20 %. However, when the influence of wall temperature is disregarded, the prediction accuracy remains at 94.2 %, with an error margin still maintained within ±20 %. Additionally, the integration of these correlations and models with advanced optimization techniques can enable development of optimal S-CO₂ system configurations.