共查询到20条相似文献,搜索用时 78 毫秒
1.
Heat and Mass Transfer Enforcement of Vibrating Fluidized Bed 总被引:1,自引:0,他引:1
HeatandMassTransferEnforcementofVibratingFluidizedBed¥ChuZhide;YangJunhong;LiXuhui;SongYang(DepartmentofThermalEnergyEngineer... 相似文献
2.
Chunlin Xia 《热科学学报(英文版)》1994,3(2):110-116
NumericalStudyofHeatTransferEnhancementbyLiquidFilmontheWalls¥ChunlinXia(DepartmentofPowerEngineering,NanjingUniversityofAero... 相似文献
3.
ConvectiveHeatandMassTransferinWateratSuper-CriticalPressuresunderHeatingorCoolingConditionsinVerticalTubes¥Pei-XueJiang;Ze-P... 相似文献
4.
S.C. Saxena 《热科学学报(英文版)》1994,3(3):211-215
HydrodynamicandHeatTransferCharacteristicsofMagnetofluidizedBedsS.C.Saxena(DepartmentofChemicalEngineering,TheUniversityofIll... 相似文献
5.
Suofang Wang 《热科学学报(英文版)》1995,4(1):38-43
AnExperimentalandNumericalStudyofNaturalConvectionHeatTransferinHorizontalAnnulibetweenEccentricCylinders¥WangSuofang(Departm... 相似文献
6.
This paper presents the results of experiments and numerical simulation of the turbulent swirling flow and heattransfer in a duct.The calculated results are in good agreement with data obtained by measurements.It isfound that the swirling flow promotes heat transfer to the wall of the duct;the swirl numbers are dependentupon the vane exit angles of the swirler,distance from the swirler and the duct Reynolds number.But the decayof swirling flow in streamwise direction is related to local Reynolds numbers and is independent of the swirlerexit angle.The swirl flow characteristics presented in this paper may be used for engineering purposes. 相似文献
7.
A numerical study is reported of laminar natural convective heat and mass transfer on a vertical cooled plate for water containing metal corrosion products at super-critical pressures. The influence of variable properties at super-critical pressures on natural convection has been analyzed. The difference between heat and mass transfer under cooling or heating conditions is also discussed and some correlations for heat and mass transfer under cooling conditions are recommended. 相似文献
8.
Yuwen Zhang Zhongqi Chen Department of Power Machinery Engineering Xi''''an Jiaotong University Xi''''an China 《热科学学报(英文版)》1992,1(3):184-188
Analytical solution is obtained of coupled laminar heat-mass transfer in a tube with uniform heat flux. This corresponds to the case when a layer of sublimable material is coated on the inner surface of a tube with its outer surface heated by uniform heat flux and this coated material will sublime as gas flows throught the tube. 相似文献
9.
Local heat transfer and skin friction around the tube perimeter of coils were studied in airflow. The heat transfer experiments were performed with two different coils D/d = 23 and 15.6, and skin friction experiments were performed with three different coils D/d = 25, 13.3 and 6.67 In the wide range of Re number from 4×103 till 105 . Variation of the local heat transfer around the perimeter and along the tube was defined. The behavior of the shear stresses at the wall and of the flow modes were studied. Investigations of the heat transfer indicated that with the increase of D/d the difference between heat transfer in the initial thermal section and the stabilized heat transfer increases. Investigations of the shear stress and its fluctuations indicated that, in large-curvature coils, the transition from laminar-vortex flow to turbulent flow around the tube perimeter takes place at different values of Re. In the region of the external generatrix of the bend, the transition occurs at smaller Re, whereas a 相似文献
10.
Corrosion products of structural materials when contained in water usually are in two states:soluble state andcolloidal particles with diameter about 10~(-3)—10~(-1)μm.Deposits of such corrosion products on tube surfacesunder high pressure will jeopardize the operating economy of power plant equipment and even result in accidents.A numerical study is reported in this paper of the natural convective heat and mass transfer on a vertical heatedplate subject to the first or mixed kind of boundary conditions for high-pressure water(P=17MPa)containingmetal corrosion products with consideration of variable thermophysical properties. 相似文献
11.
The problem of cooling electronic components has become a subject of special interest in recent years due to the increasing capacity and rapidly decreasing size of electronic components. Direct contact cooling using multiple jet impingement is considered the most effective method. The heat transfer problem is complex and a better understanding of the jet impingement method is essential for the proper application of this method for electronic cooling. Investigations were carried out using an electrically heated test plate. Heat flux in the range of 25 to $200 \ \hbox{W/cm}^{2}$ , which is a typical requirement for cooling high power electronic components was dissipated using 0.5‐mm diameter water jets arranged in a 7×7 array with a pitch of 3 mm. Temperature difference between the test plate and water was within $30 \ ^{\circ}\hbox{C}$ . Tests were performed in the flow rate range of 22 to 40 ml/min, resulting in a Reynolds number range of 1100 to 1750. Results show a significant increase in the heat transfer coefficient or Nusselt number with an increase in heat flux. The effect of the flow rate or Reynolds number on the heat transfer coefficient is found to be negligible. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20291 相似文献
12.
在第二类吸收式热泵中对螺旋槽管的换热性能研究 总被引:1,自引:0,他引:1
为了提高在以溴化锂为工质的第二类吸收式热泵吸收器的性能,在第二类吸收式热泵吸收器内对不锈钢螺旋槽管,即不锈钢光滑管的传热传质性能进行了实验研究.发现螺旋槽管的传热传质性能约为光滑管3倍,螺旋槽管内热媒工质-水的流体阻力系数是光滑管的17~20倍;应用于第二类吸收式热泵中间大大降低换热面积,促进热泵的高效紧凑化. 相似文献
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14.
Experimental and numerical investigation of heat transfer and fluid flow were conducted for classic heat exchanger elements (flat plate with fin-tubes in-line, staggered and with vortex generators) and corrugated-undulated ducts under transitional and weakly turbulent conditions.The dependence of average heat transfer and pressure drop on Reynolds number and geometrical parameters was investigated. Distributions of local heat transfer coefficient were obtained by using liquid crystal thermography and surface-averaged values were computed. Three-dimensional numerical simulations were conducted by a finite-volume method using a low-Reynolds number k-e model under the assumption of fully developed flow. Computed flow fields provided otherwise inaccessible information on the flow patterns and the mechanisms of heat transfer enhancement. 相似文献
15.
Two methods for assessing thermal performance were evaluated for four kinds of forced convective heat transfer augmentations. On method uses the first law of thermodynamics, i.e., the heat transfer improvement at (1) constant Reynolds number, (2) constant pressure loss, and (3) constant pumping power. The other method uses the second law of thermodynamics, i.e., the entropy generation. The first method restricts the effective region and the second method supplies the condition for achieving the minimum entropy generation rate. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(2): 142–154, 1998 相似文献
16.
强化换热的方法及新进展 总被引:1,自引:0,他引:1
介绍了强化传热技术的概念、分类方法以及发展过程,总结了近几年出现的强化换热新技术、新方法。主要包括新型强化换热材料及其工质的应用、各种异型强化换热管的应用以及内插物强化换热技术,其中以新型强化换热材料及工质的介绍为重点。这些新型材料和工质包括多孔材料、液态金属和纳米流体。最后分析了目前我国强化换热技术的实际应用情况及存在的问题,提出了推广建议,对从事强化换热技术研究的工作者提供一定的参考。 相似文献
17.
Detailed heat transfer measurements were performed by using 178 thermocouples in a channel with pin fin array. Local heat transfer coefficients and local heat transfer enhancement coefficients were obtained for eight Reynolds numbers ranging from 2000 to 100,000 on the endwall of the channel. The endwall boundary conditions for heat transfer investigation are heating the bottom endwall and heating symmetrically the bottom and top endwalls with constant heat flux. The mechanism of heat transfer enhancement with pin fin array has been discussed. © 2001 Scripta Technica, Heat Trans Asian Res, 30(7): 533–541, 2001 相似文献
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Experiments have been performed to investigate the effect of coiled spring inserts on heat transfer, pressure drop, and performance parameters of a triple tube heat exchanger (TTHX). Three different spring inserts having a pitch of 5, 10, and 15 mm are used and the diameter of the spring wire is taken as 1 mm. The experiments were carried out under a turbulent flow regime, with water as a working medium in parallel and counter flow configurations. The variation in different performance characteristics like heat transfer coefficient, Nusselt number, and effectiveness have been compared at various Reynolds numbers ranging between 4000 and 16,000 in the considered flow patterns. The Nusselt number of TTHX with the lowest pitch spring is found to be higher than that of the plain TTHX by 57.27% at Re = 4000 for the counter flow configuration. Both the thermal performance factor and effectiveness increased as the pitch of the spring insert was decreased. The effectiveness of TTHX with the lowest pitch spring insert is found higher than that of the plain TTHX by 43.84% in the counter flow pattern. 相似文献
20.
3-D numerical simulations were presented for laminar flow and heat transfer characteristics in a rectangular channel with
vortex generators. The effects of Reynolds number (from 800 to 3 000), the attack angle of vortex generator (from 15° to 90°)
and the shape of vortex generator were examined. The numerical results were analyzed based on the field synergy principle.
It is found that the inherent mechanism of the heat transfer enhancement by longitudinal vortex can be explained by the field
synergy principle, that is, the second flow generated by vortex generators results in the reduction of the intersection angle
between the velocity and fluid temperature gradient. The longitudinal vortex improves the field synergy of the large downstream
region of longitudinal vortex generator (LVG) and the region near (LVG); however, transverse vortex only improves the synergy
of the region near vortex generator. Thus, longitudinal vortex can enhance the integral heat transfer of the flow field, while
transverse vortex can only enhance the local heat transfer. The synergy angle decreases with the increase of Reynolds number
for the channel with LVG to differ from the result obtained from the plain channel, and the triangle winglet performs better
than the rectanglar one under the same surface area condition.
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Translated from Journal of Xi’an Jiaotong University, 2006, 40(9): 996–1000 [译自: 西安交通大学学报] 相似文献