Numerical simulation of two-phase steam ejector applied in novel loop heat pipe
As an efficient passive phase-change heat transfer device,loop heat pipe(LHP)is widely used in industrial fields such as heat dissipation of high-heat-flux electronic devices.Based on previous research,flat-plate LHP coupled with a micro two-phase steam ejector can significantly improve heat transfer performance.However,the internal flow and heat transfer mechanisms of micro two-phase steam ejector were still unclear,making it difficult to perform forward design and theoretical modeling of novel LHP.The effects of steam-water parameters and mixing chamber structure on the performance and internal flow field distribution of the two-phase steam ejector were studied through numerical simulation.The results show that a condensation shock wave exists downstream of the throat.As back pressure increases,the position gradually moves towards the throat.The intensity of condensation shock wave is positively correlated with back pressure,steam mass flow rate and mixing chamber length,while negatively correlated with water temperature.The maximum back pressure of the ejector is in the range of 40-125 kPa and positively correlated with heat load and water temperature,while negatively correlated with mixing chamber length.Through extensive simulation,the influence of water temperature and mixing chamber length on the operating state and pressure ratio of two-phase steam ejector under design power were obtained.