The non-uniformity of gas–liquid mixture is a critical issue which leads to the heat transfer deterioration of spiralwound heat exchangers(SWHEs).Two-phase mass flow rate and the content of gas are important paramete...The non-uniformity of gas–liquid mixture is a critical issue which leads to the heat transfer deterioration of spiralwound heat exchangers(SWHEs).Two-phase mass flow rate and the content of gas are important parameters as well as structural parameters which have prominent influences on flow distribution uniformity of SWHE shell side.In order to investigate the influences of these parameters,an experimental test system was built using water and air as mediums and a novel distributor named"tubes distributor"was designed.The effects of mass flow rate and the content of gas on two-phase distribution performance were analyzed,where the mass flow rate ranged from 28.4 to 171.9 kg·h-1 and the content of gas changed from 0.2 to 0.8,respectively.The results showed that the mixture mass flow rate considerably influenced the liquid distribution than that of gas phase and the larger mass flow rate exhibited the better distribution uniformity of two-phase flow.It was also found that the tubes distributor had the better two-phase uniformity when the content of gas was around 0.4.Tube diameter played an important role in the distribution of gas phase and slit width was more significant for the uniformity of liquid phase.展开更多
数据中心冷却系统是数据中心能耗最大的辅助设备,可占其整体能耗40%以上。为有效提升数据中心冷却系统能效,各种新型冷却方案层出不穷,冷板式液冷技术更是解决数据中心内高热流密度芯片散热的有效手段。冷量分配单元(Coolant distributi...数据中心冷却系统是数据中心能耗最大的辅助设备,可占其整体能耗40%以上。为有效提升数据中心冷却系统能效,各种新型冷却方案层出不穷,冷板式液冷技术更是解决数据中心内高热流密度芯片散热的有效手段。冷量分配单元(Coolant distribution unit-CDU)是冷板液冷技术的关键部件,决定了冷量分配的均匀性和经济性。为保障机柜整体的运行稳定性,CDU所设计的冷量分配必须是使最少制冷量的支路也可满足高热密度芯片的散热需求。本文以某一型号的数据机房CDU的分流管作为研究对象,通过数值模拟的方式,以分流管的流量分配均匀性、系统阻力作为分流管性能的评价指标,探究主管断面边长和支管管径对分流管性能的影响,并通过调整合适的主管和支管管径实现流量均匀分配的目的。展开更多
Flow distribution headers play a major role in heat exchangers.The selection of header diameter,branch pipe diameter,branch pipe spacing etc.is based on the designer＇s experience and general guide lines.The proper se...Flow distribution headers play a major role in heat exchangers.The selection of header diameter,branch pipe diameter,branch pipe spacing etc.is based on the designer＇s experience and general guide lines.The proper selection of the header dimensions will yield uniform flow distribution in heat exchangers,which in turn will enhance the heat exchanger efficiency.In this work,the flow distribution in branch pipes and the pressure variation across the branch pipes in laminar and low turbulence region is studied with two models of the inlet dividing headers.When the numerical analysis has been applied,its inability to predict the no flow condition through the branch pipes is revealed.The results are presented in the form of flow rate ratio through branch pipes and nondimensional coefficients across branch pipes which are useful to apply the existing mathematical models for the present experimental setup.展开更多
本文利用计算流体力学(CFD)方法对某等离子增强化学气相沉积(Plasma Enhanced Chemical Vapor Deposition,PECVD)反应室流场进行了数值模拟研究,通过改变匀流板布孔方式、进气管与匀流板距离、进气管出口形状和角度、压强等条件,研究反...本文利用计算流体力学(CFD)方法对某等离子增强化学气相沉积(Plasma Enhanced Chemical Vapor Deposition,PECVD)反应室流场进行了数值模拟研究,通过改变匀流板布孔方式、进气管与匀流板距离、进气管出口形状和角度、压强等条件,研究反应器内流动的相应变化,给出了获得薄膜生长所需的最佳输运过程的条件,以形成稳定均匀的流场,从而保证薄膜的生长质量。根据本文优化后的匀流装置已实际加工应用,取得良好效果。展开更多
基金Supported by the research funds from MIIT program on High Technology Research Program of Ship(2013K4181).
文摘The non-uniformity of gas–liquid mixture is a critical issue which leads to the heat transfer deterioration of spiralwound heat exchangers(SWHEs).Two-phase mass flow rate and the content of gas are important parameters as well as structural parameters which have prominent influences on flow distribution uniformity of SWHE shell side.In order to investigate the influences of these parameters,an experimental test system was built using water and air as mediums and a novel distributor named"tubes distributor"was designed.The effects of mass flow rate and the content of gas on two-phase distribution performance were analyzed,where the mass flow rate ranged from 28.4 to 171.9 kg·h-1 and the content of gas changed from 0.2 to 0.8,respectively.The results showed that the mixture mass flow rate considerably influenced the liquid distribution than that of gas phase and the larger mass flow rate exhibited the better distribution uniformity of two-phase flow.It was also found that the tubes distributor had the better two-phase uniformity when the content of gas was around 0.4.Tube diameter played an important role in the distribution of gas phase and slit width was more significant for the uniformity of liquid phase.
文摘数据中心冷却系统是数据中心能耗最大的辅助设备,可占其整体能耗40%以上。为有效提升数据中心冷却系统能效,各种新型冷却方案层出不穷,冷板式液冷技术更是解决数据中心内高热流密度芯片散热的有效手段。冷量分配单元(Coolant distribution unit-CDU)是冷板液冷技术的关键部件,决定了冷量分配的均匀性和经济性。为保障机柜整体的运行稳定性,CDU所设计的冷量分配必须是使最少制冷量的支路也可满足高热密度芯片的散热需求。本文以某一型号的数据机房CDU的分流管作为研究对象,通过数值模拟的方式,以分流管的流量分配均匀性、系统阻力作为分流管性能的评价指标,探究主管断面边长和支管管径对分流管性能的影响,并通过调整合适的主管和支管管径实现流量均匀分配的目的。
文摘Flow distribution headers play a major role in heat exchangers.The selection of header diameter,branch pipe diameter,branch pipe spacing etc.is based on the designer＇s experience and general guide lines.The proper selection of the header dimensions will yield uniform flow distribution in heat exchangers,which in turn will enhance the heat exchanger efficiency.In this work,the flow distribution in branch pipes and the pressure variation across the branch pipes in laminar and low turbulence region is studied with two models of the inlet dividing headers.When the numerical analysis has been applied,its inability to predict the no flow condition through the branch pipes is revealed.The results are presented in the form of flow rate ratio through branch pipes and nondimensional coefficients across branch pipes which are useful to apply the existing mathematical models for the present experimental setup.
文摘本文利用计算流体力学(CFD)方法对某等离子增强化学气相沉积(Plasma Enhanced Chemical Vapor Deposition,PECVD)反应室流场进行了数值模拟研究,通过改变匀流板布孔方式、进气管与匀流板距离、进气管出口形状和角度、压强等条件,研究反应器内流动的相应变化,给出了获得薄膜生长所需的最佳输运过程的条件,以形成稳定均匀的流场,从而保证薄膜的生长质量。根据本文优化后的匀流装置已实际加工应用,取得良好效果。
