The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative h...The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative heat transfer in the turbulent model would lower the predicted convective heat transfer coefficient. Predictions of the new model resulted in a prominent deviation from that predictions of the normal model in the case of large mass flow rate and low wall heat flux. This deviation will be decreased with increasing wall heat flux, such that it will be asymptotic zero at very high wall heat flux. Predictions of the new model agreed well with the current experimental measurements. This study has verified that the Reynolds number is not the sole crucial parameter for heat transfer of falling liquid film flow, and wall heat flux will be another important independent parameter. This result is consistent with our previous studies.展开更多
Effects of the flow pattern of intertubular liquid film on mass and heat transfer synergies in a falling-film dehumidification system with horizontal pipes are studied.A flow model of the dehumidifying solution betwee...Effects of the flow pattern of intertubular liquid film on mass and heat transfer synergies in a falling-film dehumidification system with horizontal pipes are studied.A flow model of the dehumidifying solution between horizontal pipes is established using Fluent software,the rule of transitions of the flow pattern between pipes is studied,critical Reynolds numbers of flow pattern transitions are obtained,and the accuracy of the model is verified by experiments.The mass transfer synergy angle and heat transfer synergy angle are respectively used as evaluation criteria for the mass transfer synergy and heat transfer synergy,and distribution laws of the synergy angles for droplet,droplet columnar and curtain flow patterns are obtained.Simulation results show that the mass transfer synergy angles corresponding to droplet,droplet columnar and curtain flow patterns all rise to a plateau with time.The mean mass-transfer synergy angle is 98°for the droplet flow pattern,higher than 96.5°for the droplet columnar flow pattern and 95°for the curtain flow pattern.The results show that the mass transfer synergy of the droplet flow pattern is better than that of the droplet columnar flow pattern and that of the curtain flow pattern.展开更多
The flow of a freely falling liquid film of low Reynolds number down a vertical long periodic sine-shaped wavy plate of small corrugations is researched theoretically. A model based on perturbation method and power se...The flow of a freely falling liquid film of low Reynolds number down a vertical long periodic sine-shaped wavy plate of small corrugations is researched theoretically. A model based on perturbation method and power series is presented. A stream function is introduced into the governing equations and two sets of equations describing the film flow separately at zeroth and first order are developed. The zeroth order equation is solved directly. The first order equations is solved at the leading approximation. Effect of parameters Re, M, λ and ε on the free surface wave of film is discussed.展开更多
基金Supported by the National Natural Science Foundation of China (No. 59995550-3) and Science Funds from the Ministry of Education (No. 97000357).
文摘The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial eveiporative heat transfer in the turbulent model would lower the predicted convective heat transfer coefficient. Predictions of the new model resulted in a prominent deviation from that predictions of the normal model in the case of large mass flow rate and low wall heat flux. This deviation will be decreased with increasing wall heat flux, such that it will be asymptotic zero at very high wall heat flux. Predictions of the new model agreed well with the current experimental measurements. This study has verified that the Reynolds number is not the sole crucial parameter for heat transfer of falling liquid film flow, and wall heat flux will be another important independent parameter. This result is consistent with our previous studies.
基金Project(2016YFC0700100)supported by the National Key R&D Program of ChinaProject(JDJQ20160103)supported by the Promotion of the Connotation Development Quota Project of Colleges and Universities-Outstanding Youth of Architectural University,China。
文摘Effects of the flow pattern of intertubular liquid film on mass and heat transfer synergies in a falling-film dehumidification system with horizontal pipes are studied.A flow model of the dehumidifying solution between horizontal pipes is established using Fluent software,the rule of transitions of the flow pattern between pipes is studied,critical Reynolds numbers of flow pattern transitions are obtained,and the accuracy of the model is verified by experiments.The mass transfer synergy angle and heat transfer synergy angle are respectively used as evaluation criteria for the mass transfer synergy and heat transfer synergy,and distribution laws of the synergy angles for droplet,droplet columnar and curtain flow patterns are obtained.Simulation results show that the mass transfer synergy angles corresponding to droplet,droplet columnar and curtain flow patterns all rise to a plateau with time.The mean mass-transfer synergy angle is 98°for the droplet flow pattern,higher than 96.5°for the droplet columnar flow pattern and 95°for the curtain flow pattern.The results show that the mass transfer synergy of the droplet flow pattern is better than that of the droplet columnar flow pattern and that of the curtain flow pattern.
基金Acknowledgement： This work is supported by Natural Science Foundation of Tianjin of China （No. 07JCYBJC01300）.
文摘The flow of a freely falling liquid film of low Reynolds number down a vertical long periodic sine-shaped wavy plate of small corrugations is researched theoretically. A model based on perturbation method and power series is presented. A stream function is introduced into the governing equations and two sets of equations describing the film flow separately at zeroth and first order are developed. The zeroth order equation is solved directly. The first order equations is solved at the leading approximation. Effect of parameters Re, M, λ and ε on the free surface wave of film is discussed.
