The study deals with a new regenerative air heat exchanger with an intermediate heat carrier used in the systems of room ventilation.A physical and mathematical model of the heat transfer process is proposed.The...The study deals with a new regenerative air heat exchanger with an intermediate heat carrier used in the systems of room ventilation.A physical and mathematical model of the heat transfer process is proposed.The influence of design and operating parameters on the temperature efficiency of the heat exchanger is analyzed.The possibility of a significant increase in its efficiency with a decrease in the packing diameter is shown.As a result of calculations,it was found that with a decrease in the filling height,the maximum temperature efficiency shifted towards a decrease in the air flow rate from its value determined from the equality of water equivalents of liquid and air.展开更多
A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube he...A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube heat exchangers at high pressure with the advantage of compact space of heat exchangers. Thermal analysis on the two processes of forced convection and vaporization type heat transfer in the spiral wound tubes and vapor condensation /re-boiling type of heat transfer via intermediate fluid in shell side shows the feasibility of this promising technology.展开更多
The intermediate heat exchanger for enhancement heat transfer is the important equipment in the usage of nuclear energy. In the present work, heat transfer and entropy generation of an intermediate heat exchanger(IHX)...The intermediate heat exchanger for enhancement heat transfer is the important equipment in the usage of nuclear energy. In the present work, heat transfer and entropy generation of an intermediate heat exchanger(IHX) in the accelerator driven subcritical system(ADS) are investigated experimentally. The variation of entropy generation number with performance parameters of the IHX is analyzed, and effects of inlet conditions of the IHX on entropy generation number and heat transfer are discussed. Compared with the results at two working conditions of the constant mass flow rates of liquid lead-bismuth eutectic(LBE) and helium gas, the total pumping power all tends to reduce with the decreasing entropy generation number, but the variations of the effectiveness, number of transfer units and thermal capacity rate ratio are inconsistent, and need to analyze respectively. With the increasing inlet mass flow rate or LBE inlet temperature, the entropy generation number increases and the heat transfer is enhanced, while the opposite trend occurs with the increasing helium gas inlet temperature. The further study is necessary for obtaining the optimized operation parameters of the IHX to minimize entropy generation and enhance heat transfer.展开更多
铅铋快堆(lead-bismuth fast reactor,LFR)与超临界二氧化碳(supercritical CO_(2),S-CO_(2))循环耦合系统是提升核能利用效率,优化核能应用现状的突破性技术。为了准确把握该系统中耦合换热这一关键问题的发展动态与现状,从中间换热器...铅铋快堆(lead-bismuth fast reactor,LFR)与超临界二氧化碳(supercritical CO_(2),S-CO_(2))循环耦合系统是提升核能利用效率,优化核能应用现状的突破性技术。为了准确把握该系统中耦合换热这一关键问题的发展动态与现状,从中间换热器技术开发、印刷电路板式换热器(printed circuit board heat exchanger,PCHE)流道优化、液态铅铋合金(liquid lead bismuth eutectic,LBE)及S-CO_(2)流动传热机理研究、LBE及S-CO_(2)耦合对流换热机理研究等角度出发,全面归纳总结了相关的实验研究与数值模拟成果。研究结果表明,Z型PCHE加工难度适中,换热性能优秀,弯折处加入直道或弯弧可在传热速率略微下降的前提下大幅降低换热器内压降,明确该型换热器是目前主流选择,并给出了PCHE的结构优化设计思路;液态LBE流动传热实验研究存在边界条件范围窄的问题,对比已有的传热预测关联式,对棒束、圆管等不同条件给出相应的传热预测关联式;对比分析适用于液态LBE的数值模拟方法,给出了可靠的利用雷诺时均方法的湍流模型与湍流普朗特数模型,阐释了利用四方程模型数值模拟的原理与优势;系统总结了应用于PCHE中的S-CO_(2)传热关联式,LBE与S-CO_(2)耦合换热研究现状与存在的问题。目前LBE与S-CO_(2)直接耦合换热的研究成果较缺乏,仍无成熟结论明确哪种换热器结构最合适,哪种数值模型有最优的可靠性与最小的偏差值,仍需针对不同应用场景具体考虑。本文明晰了铅铋-超临界二氧化碳耦合换热应用研究的方向与困难所在,对其他类似的新型多工质耦合换热系统的开发也具有重要指导意义。展开更多
基金This work was supported by a state contract with the IT SB RAS№121031800217-8.
文摘The study deals with a new regenerative air heat exchanger with an intermediate heat carrier used in the systems of room ventilation.A physical and mathematical model of the heat transfer process is proposed.The influence of design and operating parameters on the temperature efficiency of the heat exchanger is analyzed.The possibility of a significant increase in its efficiency with a decrease in the packing diameter is shown.As a result of calculations,it was found that with a decrease in the filling height,the maximum temperature efficiency shifted towards a decrease in the air flow rate from its value determined from the equality of water equivalents of liquid and air.
基金supported by grants from the Fundamental Research Funds for the Central Universities(DUT12JN01)the National Natural Science Foundation of China(51106017)
文摘A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube heat exchangers at high pressure with the advantage of compact space of heat exchangers. Thermal analysis on the two processes of forced convection and vaporization type heat transfer in the spiral wound tubes and vapor condensation /re-boiling type of heat transfer via intermediate fluid in shell side shows the feasibility of this promising technology.
基金supported by the National Natural Science Foundation of China(No.51376177)the"Strategic Priority Research Program"of Chinese Academy of Sciences(No.XDA03010500)
文摘The intermediate heat exchanger for enhancement heat transfer is the important equipment in the usage of nuclear energy. In the present work, heat transfer and entropy generation of an intermediate heat exchanger(IHX) in the accelerator driven subcritical system(ADS) are investigated experimentally. The variation of entropy generation number with performance parameters of the IHX is analyzed, and effects of inlet conditions of the IHX on entropy generation number and heat transfer are discussed. Compared with the results at two working conditions of the constant mass flow rates of liquid lead-bismuth eutectic(LBE) and helium gas, the total pumping power all tends to reduce with the decreasing entropy generation number, but the variations of the effectiveness, number of transfer units and thermal capacity rate ratio are inconsistent, and need to analyze respectively. With the increasing inlet mass flow rate or LBE inlet temperature, the entropy generation number increases and the heat transfer is enhanced, while the opposite trend occurs with the increasing helium gas inlet temperature. The further study is necessary for obtaining the optimized operation parameters of the IHX to minimize entropy generation and enhance heat transfer.
