共查询到20条相似文献,搜索用时 15 毫秒
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In this paper,the comparative experimental research that air flows through theout-surface of a single row finned tubes is done in a drawing wind tunnel and the three differnetshapes of rectangluar finned tubes are compared with a plain finned tube that is usually used in therefrigerant heat exchanger, the useful results are obtained. The results show that,in the range ofwind velocity flowing through the marrowest area, W_(max)=2.5m/s to 8.5m/s,the average convec-tion heat transfer coefficient of the two-side V-groove finned tube is higher than that of rectangluarplain finned tube,It is a new type finned tube that has good heat transfer performance and it isworth poplarlzing. 相似文献
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This paper discusses the mechanism of the reduction ofheat flux through a roof pond with floating plants.A thermal model ispresented and the analytical results are obtained.The results are ingood agreement with the experimental observation. 相似文献
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Liu Hong Chen Yuanguo 《保鲜与加工》1991,(3):35-39
The present paper discribes experiment research of effect of the inclination on heat transfer on 9 kinds of plain tubes in atomosphere, working fluids are distill water and ethanel. Experinent result show very obvious effect of inclination of pool boiling heat transfer. The larger heat transfer increases, the larger the inclination does. The correlation obtained on 524 experiment data can be used for reference to engineering design in prospect of heat transger coefficient. 相似文献
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Long Enshen 《保鲜与加工》1993,(2)
This paper introduces the clarifying influence of the intertube spacing, the tube arrangement,the heat flux and the working fluid on boiling heat tra(?)sfer of smooth tube bundles. The tube bundles include the arrangements of twin tubes, triple tubes, seven tubes and thirteen tubes. The relative intertube spacing of the tube bundles is from 0. 9 to 3. 3. Experimental results show that the tube position and intertube spacting have no effect on boiling curves for the region of fully-devoloped boiling. And they considerably affect the heat transfer coefficient for the transition region between natural convection and nucleate boiling. In general,the heat transfer coefficient in the transition region for the upper tubes can be enhanced by 0. 5 to 1. 5 times. 相似文献
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Shi Chengming Xin Mingdao Chen Yuanguo 《保鲜与加工》1992,(4):15-20
An analytical model for the separate type heat pipe exchanger with three different fluids is presented. A univeral basic temperature transfer matrix equation can be applied to predict the heat transfer performance of parallel-or counter-flow in which heat is transfered between one hot fluid and two cold fluids or between two hot fluids and one cold fluid. The calculation of a real engineering example proves the proposal model to be reliable. 相似文献
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Li Longjian Zhang Hongji 《保鲜与加工》1991,(2):79-84
In this paper the heat transfer in the tube-mouth region of the high temperatur heat exchange equipment is deeply analysed. The effect; of the heat conducting cross-section area of the tube-mouth region and axial heat conduction along the tube on the temperature field is emphatically examined by numerical computation, and then the relation of the highest temperature in the tube with the elongated tube length is established. The computed results in this paper are compared with those without taking account of these two factors. It is shown that the effect can not be ignored for the corrosion-protection by controlling temperature. 相似文献
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Li Yourong 《保鲜与加工》1991,(5):64-68
A second law analysis is carried out on convective heat transfer through a horizontal annulus with constant heat flux. The entropy generation rate expression is obtained,and the influence of heat transfer across a finite temperature difference and fluid friction on the entropy generation rate is discussed. The optimum geometric parameters of a horfzontal annulus is found for which the entropy generated is minimum. The optimum fluid velocity which corresponds to the optimum geometric parameters is recommended. 相似文献
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Dong Liang Zhang Hongji Chen Junguo 《保鲜与加工》1990,(1):35-41
On the basis of the mechanism of the boiling heat transfer on low finned tube, the influence of the geometric parameters of low finned tube on boiling heat transfer is synthetically analyzed and relevant criteria which affect the optimal structure of low finned tube is deduced in this paper. The boiling heat transfer experiment on low finned tube is conducted. Distilled water and R-113 are used as test fluids The experiment is performed at local atmospheric pressure. Synthesizing a large amount of experimental data, the semiempirical equations for the optimal geometric parameters of lowfinned tube are established 相似文献
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Xia Jiliang Xin Mingdao Fu Min 《保鲜与加工》1992,(5):31-37
Flow and heat transfer are numerically studied in a rectangular fin groove when the fin base is heated with contsant temperature. Rayleigh number, inclination , aspect ratio, thick ness and conductivity of the fin are systematically changed to examine their effects. Five flow patterns are found, local and average characteristics are given, and the mechanism of heat transfer is discussed. The results can be used as a reference for fin designs. 相似文献
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Da Yang Xin Mingdao 《保鲜与加工》1989,(5):27-34
An analytical model was proposed for the condensation heat transfer on the horizontal low-finned tube attached by a porous drainage strip, and compared with the experimental data with a good agreement. The permeability of the porous drainage strip was also experimentally determined. 相似文献
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Zhang Hongji Li Longjian 《保鲜与加工》1992,(2):32-39
The effect of the convective heat transfer in the entrance region of the tube on the temperature field and the maximum temperature of the tube material in the tube -mouth region of the high temperature heat exchange equipment is examined by numerical analysis. The computations on the basis of four different formulas for convection heat transfer coefficient are performed. The computed results indicate that the efect can not be ignored as for heat protection of the tube -mouth region and it is resapnable and secure that the mean convective heat transfer coefficient with taking account of the effect of the entrance region is used in the thermal design of the tube -mouth region. 相似文献
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隔温式房式仓储粮技术的应用探讨 总被引:2,自引:0,他引:2
对隔温式密闭房式仓储粮性能进行研究。结果表明,隔温式密闭房式仓具有良好的降氧、而高温性能,可以延缓储粮品质陈化,防虫、防霉、防鼠,适合于各种粮食储藏。 相似文献
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THERMODYNAMIC ANALYSIS AND PERFORMANCE EVALUATION OF CONVECTIVE HEAT TRANSFER THROUGH DUCTS 总被引:1,自引:0,他引:1
Li Yourong Jin Mingcong Tang Jingwen 《保鲜与加工》1992,(3):68-72
A second law analysis is carried out on convective heat transfer in fully developed region with constant wall temperature through circular, trianglar and rectangular ducts. Besides, the entropy generation rate expression is obtained and the loss rate of available energy in convective heat transfer processes is defined as well. At the same time, the influence of initial temperature difference between fluid and wall as well as the influence of fluid friction on the loss rate of available energy is discussed. Then, the thermodynamic performances of several typical ducts are compared. Finally , the optimum initial temperature difference with the minimum loss rate of available energy is also obtained. 相似文献
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谷物呼吸热值测定研究 总被引:1,自引:0,他引:1
谷物呼吸热值测定是粮食通风散热课题的核心问题.本文利用气体分析仪和恒温水槽测定谷物呼吸对氧气的消耗量和二氧化碳的生成量,作者首次提出了同时考虑有氧呼吸和无氧呼吸两因素,对呼吸方程进行配平,从而由呼吸生成物与呼吸反应物之间生成??值之差来精确计算出呼吸热. 数据处理全过程由微机完成. 相似文献