A real-time modeling approach of transient thermal behavior for phase change cold storage heat exchanger

The phase change cold storage heat exchanger is a critical component in spacecraft thermal management systems. However, accurate simulation of its dynamic thermal response under strongly unsteady boundary conditions requires high-fidelity numerical models and considerable computational resources. Existing modeling approaches are unable to resolve the transient thermal field distribution of phase change cold storage heat exchangers in real time. In this study, a numerical modeling approach for the cold storage heat exchanger based on the phase change enthalpy method is proposed for real-time prediction of transient thermal behavior. A transient numerical model of the cold storage heat exchanger is developed under various boundary conditions. The results show that the proposed approach exhibits good numerical stability. Across the 432 simulation cases, the cumulative residual remains below 10⁻¹⁰. Under the experimental conditions, the approach demonstrates good temperature prediction accuracy, with a maximum error of 8.4% for the melting process under the constant heat flux boundary and 16% for the solidification process under the convective heat transfer boundary. The simulation time for all the cases is much lower than the physical time span of 300 s, with average values of 41.3 s, 43.5 s, and 47.2 s for the constant temperature, constant heat flux, and convective heat transfer boundaries, respectively. The proposed approach enables the real-time simulation of the cold storage heat exchangers under dynamic operating conditions with high accuracy and lower time.