Separation mechanism of T-junction in thermodynamic systems: A review and case verification

Abstract

• Researches on constituent separation and application of T -junction are reviewed. • Simulation on constituent separation driven by thermal field is performed. • Mechanism of active separation in T -junction is discussed. • Phase distribution and interphase mass transfer are critical to passive separation. • Density difference is a key factor for active separation of single-phase. Concentration variation of binary zeotropic mixtures can improve the cooperativity between the working fluid and thermodynamic process in thermodynamic cycle. T -junction is increasingly considered for the concentration regulating equipment in view of advantages of small volume, simple structure and low cost. In order to clarify the mechanism of the constituent separation of binary zeotropic mixtures in T -junction, researches on active and passive separation of binary zeotropic mixtures and application of T -junction are reviewed. Besides, the separation driven by thermal field is verified via numerical method in the paper. The results show that the factors that are important for constituent separation are phase distribution and interphase mass transfer. If the quantitative study on the effect of phase distribution and interphase mass transfer on the constituent distribution is performed, which will promote the application of the T -junction in practical engineering. The efficiency of the separation driven by thermal field is improved compared with that of passive separation. For difluoromethane (R32) and isobutane (R600a), the separation performance of T -junction increases with the increase of temperature difference at outlet. For R32 and R600a in liquid-phase, the mixture is not separated when the temperature difference is lower than 80 K. For R32 and R600a in gas-phase, when the temperature difference is 240 K, the separation efficiency of R32 at outlet 2 is increased up to 1.57 %.