A novel strip - coil - baffle structure used to enhance heat transfer and support the tube bundle for a tube - shell heat exchanger is proposed. the new structure can sleeve the tubes in bundle alternatively to create a vortex flow in a heat exchanger. the numerical simulation on the flow and heat transfer characteristics for this new structure heat exchanger is conducted. the computational domain consists of two strip - coil sleeved tubes and two bare tubes oppositely placed at each corner of a square. the velocity and temperature fields in such strip - coil - baffled channel are simulated using fluent software. the effects of the strip - coil - baffles on heat transfer enhancement and flow resistance in relation to the reynolds number are analyzed. the results show that this new structure bundle can enhance the heat transfer coefficient up to a range of 40 ? to 55 ? in comparison with a bare tube bundle ; meanwhile, higher flow resistance is also accompanied. it is believe that the strip - coil - baffled heat exchanger should have promising applications in many industry fields
介紹了一種用於強化管
殼式換熱器
殼側傳熱和支撐管束的螺旋折流片新型結構,該結構是對換熱器管子相間地套上螺旋折流片以產生旋
渦流動.研究模型是在正方形布置的4個管子中的2個對角管子套上螺旋折流片后形成的通道,利用fluent軟體對該上述四管通道模型的流場和溫度分佈情況進行了數值模擬;分析了四管通道模型中螺旋折流片對強化傳熱和流動阻力隨雷諾數的變化關系的影響.算例結果顯示該新型結構可比相同尺寸的光管通道中的情形傳熱系數提高約40 ? 55 ? ,同時也將伴隨較高的流動阻力.可以相信螺旋折流片式換熱器將會在許多工業領域有良好的應用前景
Abstract : a novel strip - coil - baffle structure used to enhance heat transfer and support the tube bundle for a tube - shell heat exchanger is proposed. the new structure can sleeve the tubes in bundle alternatively to create a vortex flow in a heat exchanger. the numerical simulation on the flow and heat transfer characteristics for this new structure heat exchanger is conducted. the computational domain consists of two strip - coil sleeved tubes and two bare tubes oppositely placed at each corner of a square. the velocity and temperature fields in such strip - coil - baffled channel are simulated using fluent software. the effects of the strip - coil - baffles on heat transfer enhancement and flow resistance in relation to the reynolds number are analyzed. the results show that this new structure bundle can enhance the heat transfer coefficient up to a range of 40 ? to 55 ? in comparison with a bare tube bundle ; meanwhile, higher flow resistance is also accompanied. it is believe that the strip - coil - baffled heat exchanger should have promising applications in many industry fields
文摘:介紹了一種用於強化管
殼式換熱器
殼側傳熱和支撐管束的螺旋折流片新型結構,該結構是對換熱器管子相間地套上螺旋折流片以產生旋
渦流動.研究模型是在正方形布置的4個管子中的2個對角管子套上螺旋折流片后形成的通道,利用fluent軟體對該上述四管通道模型的流場和溫度分佈情況進行了數值模擬;分析了四管通道模型中螺旋折流片對強化傳熱和流動阻力隨雷諾數的變化關系的影響.算例結果顯示該新型結構可比相同尺寸的光管通道中的情形傳熱系數提高約40 ? 55 ? ,同時也將伴隨較高的流動阻力.可以相信螺旋折流片式換熱器將會在許多工業領域有良好的應用前景
In order to avoid the shell cracking during baking process of quick investment casting based on stereolithography ( sl ) pattern, an expanding model of sl pattern - ceramic shell is proposed via analyzing the interaction between investment shell and sl pattern, then the cracking condition of investment shell is given
摘要為了解決快速熔模鑄造中型
殼開裂問題,對樹脂模型與型
殼材料在消失過程中的熱變形機理和型
殼開裂條件進行了有限元分析,建立了原型型
殼熱變形數學模型,並應用於新型燃氣
渦輪導向器的快速鑄造。
Also, the chamfer of the stay vanes entrance and the surface roughness of the flow channel were optimized by the numerical investigations
亦對固定導葉入口沖角、
渦殼壁面粗糙度對流動的影響進行了定量分析。
This paper deals with a lump - sum flow analysis of a spiral case, stay ring and vaneless annular walls for a small francis turbine by the latest cfd code
本文對常用的小型混流式水輪機渦殼、座環和無導葉環壁面內流動狀況用最新的cfd技術進行了整體數值解析。