Comparison of Quality Prediction Methods for Transient Two-Phase Systems in High-Speed Applications

The convergence of increasingly powerful electronics and significant aerodynamic heating in high-speed aircraft necessitates the use of robust thermal management systems. One potential solution involves employing a two-phase flow system, however, the ability to control transient conditions in this approach becomes essential to mitigate system instabilities. Understanding and predicting flow boiling instabilities, described by void fraction and vapor quality, is paramount to ensuring the reliability of critical avionics. Traditional energy balance methods can yield inaccurate vapor quality estimations, especially under the transient thermal loads inherent to high-speed flight. Electrical Capacitance Tomography (ECT) offers a valuable tool for experimentally measuring void fraction based on fluid permittivity. This research investigates the application of ECT-derived void fraction correlations to achieve a more accurate and real-time determination of refrigerant quality in these dynamic two-phase flow systems. The results of this work will directly contribute to the design of advanced thermal control systems capable of swiftly and effectively responding to the rapid thermal fluctuations characteristic of high-speed aircraft environments, thereby safeguarding sensitive electronics and improving overall aircraft performance.