共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
3.
4.
5.
采用数值计算方法对一种应用于半导体制冷片热端散热的翅片式热管散热器进行模拟,探究自然对流条件下不同翅片参数对散热器换热特性的影响。结合多目标遗传算法(NSGA-Ⅱ),以影响散热器散热的两个主要参数——翅片表面传热系数和肋面效率为优化目标,对散热器整体做出综合优化,并对优化结果进行K均值聚类分析,提出了翅片端优化原则。结果表明,肋面效率对散热器性能的影响有限,提高表面传热系数可显著降低散热器总热阻;与未优化方案相比,所选优化方案可使基板热端面温度下降3.5K,散热器热阻降低18.22%。 相似文献
6.
7.
8.
9.
《内燃机工程》2016,(5)
利用数值模拟的方法对履带车用锯齿型翅片散热器的翅片间距和翅片切口长度进行结构优选,引入了同功耗强化传热评价指标(performance evaluation criteria,PEC),对比了不同翅片间距和翅片切口长度的散热性能。研究结果表明:翅片间距和翅片切口长度分别为2mm和4mm时,翅片的综合性能最优。根据数值计算结果研制散热器样件,利用风洞试验台对翅片切口长度为4mm,翅片间距分别为1.5、2.0和2.5mm试验样件进行测试,试验结果与仿真结果较一致,误差在10%以内。通过试验数据拟合出适用于三种翅片间距锯齿形传热器在试验的雷诺数范围内的传热和阻力性能关联式,并分析了水侧流速对空气侧传热性能的影响。 相似文献
10.
11.
The present numerical analysis pertains to the heat transfer enhancement in a plate‐fin heat exchanger employing triangular shaped fins with a rectangular wing vortex generator on its slant surfaces. The study has been carried out for three different angles of attack of the wing, i.e., 15°, 20° and 26°. The aspect ratio of the wing is not varied with its angle of attack. The flow considered herein is laminar, incompressible, and viscous with the Reynolds number not exceeding 200. The pressure and the velocity components are obtained by solving the continuity and the Navier– Stokes equations by the Marker and Cell method. The present analysis reveals that the use of a rectangular wing vortex generator at an attack angle of 26° results in about a 35% increase in the combined spanwise average Nusselt number as compared to the plate‐triangular fin heat exchanger without any vortex generator. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20285 相似文献
12.
This study presents numerical computation results on laminar convection heat transfer in a plate‐fin heat exchanger, with triangular fins between the plates of a plate‐fin heat exchanger. The rectangular winglet type vortex generator is mounted on these triangular fins. The performance of the vortex generator is evaluated for varying angles of attack of the winglet i.e., 20, 26, and 37° and Reynolds number 100, 150, and 200. The computations are also performed by varying the geometrical size and location of the winglet. The complete Navier–Stokes equation and the energy equation are solved by the (Marker and Cell) MAC algorithm using the staggered grid arrangement. The constant wall temperature thermal boundary conditions are considered. Air is taken as the working fluid. The heat transfer enhancement is seen by introducing the vortex generator. Numerical results show that the average Nusselt number increases with an increase in the angle of attack and Reynolds number. For the same area of the LVG, the increase in length of the LVG brings more heat transfer enhancement than increasing the height. The increase in heat transfer comes with a moderate pressure drop penalty. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20318 相似文献
13.
A comparative study of effects of attack angle, length of vortex generator, height of vortex generator, fin material, fin thickness, fin pitch and tube pitch on fin performance of vortex-generator fin-and-tube heat exchanger is conducted by numerical method. The parameters of vortex-generator fin-and-tube heat exchangers are optimized by the Taguchi method. Eighteen kinds of models are made by compounding levels on each factor, and the heat transfer and flow characteristics of each model are analyzed. The results show that these six factors (fin pitch, longitudinal tube pitch, transverse tube pitch, length of vortex generator, height of vortex generator, and attack angle of vortex generator) have great influences on the JF-factor. The fin material and fin thickness have trifling effects on the JF-factor. The two optimal conditions (A1B3C3D2E1F2G1H3 and A2B2C2D3E1F2G1H3) are acquired, and the reproducibility of the results is verified by two analytical results. 相似文献
14.
Kai-Shing Yang Shu-Lin Li Ing Youn Chen Kuo-Hsiang Chien Robert Hu Chi-Chuan Wang 《International Journal of Heat and Mass Transfer》2010,53(25-26):5675-5681
This study examines the airside performance of heat sinks having fin patterns of plate fin (Type I), interrupted fin geometry (Type II), dense vortex generator (Type III), and loose vortex generator (Type IV). Test results indicate that the heat transfer performance is strongly related to the arrangement of enhancements. The interrupted and dense vortex generator configurations normally contribute more pressure drop penalty than improvements of heat transfer. This is especially pronounced when operated at a lower frontal velocity. Actually the plain fin geometry outperforms most of the enhanced fin patterns such as of Type II and Type III at the fully developed region. This is because a close spacing prevents the formation of vortex, and the presence of interrupted surface may also suffer from the degradation by constriction of conduction path. The results suggest that the vortex generators operated at a higher frontal velocity is more beneficial than that of plain fin geometry. In association with the VG-1 criteria (same pumping power and same heat transfer capacity), the results show that effective reduction of surface area can be achieved when the frontal velocities are at 3–5 m s?1 and the fin patterns are triangular, triangular attack, or two-groups dimple. The result from the present experiment suggests that the asymmetric combination such as using loose vortex generator (Type IV) can be quite effective. The triangular attack vortex generator is regarded as the optimum enhancement design for it could reduce 12–15% surface area at a frontal velocity around 3–5 m s?1. The asymmetric design is still applicable even when the fin pitch is reduced to 1 mm. 相似文献
15.
Nawaf H. Saeid 《传热工程》2018,39(2):154-161
Numerical study is carried out to investigate the effect of different fin shapes on heating a square cavity by small heating strip located at the bottom wall. The natural convection of air is considered with constant heat flux from heat source which is located at the center of the bottom wall. The width of the heating strip is assumed to be 20% of the total width of the bottom wall. The remaining (non-heated) part of the bottom wall and the top wall are adiabatic and the side walls are maintained at constant temperature. The investigation considered four shapes of aluminum fins with equal area and equal base width. The easy to fabricate fin shapes are considered as: rectangular, one triangular, two opposite triangular and two isosceles triangular shape. Other parameters considered are the total area of the fin (or the height of the fin) and the Grashof number in the laminar flow range. It is found that the heat transfer can be enhanced by either increasing the Grashof number or the height of the fins. In most of the investigated cases the heat transfer in the case of the two opposite triangular fins shape is found to be higher than that of the other shapes under the same conditions. 相似文献
16.
Experimentally investigates heat dissipation by different longitudinal fins fitted to a cylindrical heat sink under natural convection conditions. Five aluminum fin configurations at base temperatures (70°C, 85°C, 100°C, and 115°C) were studied. The first fin was plain (fin1), while second fin had a triangular edge (fin2). The rest fins have the same triangular edge but with six 1cm circular perforations near the edge (fin3). While the perforations in fin4 were in the middle longitudinal fin length. The last fin (fin5) had twelve 0.5 cm circular perforations distributed into two columns. The measurements were validated with theoretical correlation with an acceptable deviation. The results showed that fin2, fin3, fin4, and fin5 dissipate more heat by 2.4%, 8.7%, 11.4%, and 5% than the flat fin with 9.8%, 11.85%, 11.85%, and 10.82% weight reduction, respectively. The heat transfer coefficient enhanced by 7.98%, 16.81%, 12.35%, and 5.44% for fin5, fin4, fin3, and fin2, respectively. Large circular perforation was more effective to dissipate heat especially when located near the heat source as in fin4 which gives the best heat dissipation with more weight reduction. The proposed fins efficiency were greater than 92%. 相似文献
17.
18.
19.
《International Journal of Hydrogen Energy》2022,47(3):1820-1832
Heat management is crucial to the stable and high-efficiency operation of proton exchange membrane fuel cell (PEMFC) system. However, fin-tube heat exchangers (FTHE) of traditional internal combustion engine vehicles require further optimizations to be applicable to PEMFC vehicles. In the paper, a three-dimensional steady-state radiator model is developed in OpenFOAM to investigate three novel structural designs based on wavy-louvred (WL) fin and vortex generators (VGs). The established model has been carefully validated against experimental data and correlation reference. To comprehensively evaluate radiator performances, the air side heat transfer coefficient, pressure drop, outlet air temperature, heat flux, and JF factor are adopted. It is found that the FTHE with L-VGs has the highest heat transfer coefficient while the FTHE with WL-VGs has the highest pressure drop. The temperature, velocity, and pressure distribution are further demonstrated to reveal performance enhancement mechanisms. It is seen that the heat exchangers with additional VGs produce two sections of high-temperature wakes near the wall, which not only promotes the heat convection but also contributes to the heat exchange in the nearby area. Meanwhile, a low-speed vortex zone behind VGs appears and generates longitude vortex, making the air stream stay longer at fin surfaces. The air flow in FTHE with WL is not as much separated as the conventional FTHE since the zigzag wavy louver restricts flow separation. The paper gives valuable suggestions for cooling capability improvement and radiator volume diminution. 相似文献
20.
Qinguo Zhang Liangfei Xu Jianqiu Li Minggao Ouyang 《International Journal of Hydrogen Energy》2017,42(38):24504-24516
The objective of this paper is to analyze the heat transfer characteristics of plate-fin radiator for the cold air heating system of a PEMFC engine and to find the optimal parameter combination in order to reduce the power consumption. The effect of the coolant mass flow and temperature on the heat exchange performance of the radiator was investigated based on 3D porous medium model. The results, including the amount of heat transferred and temperature change and heat exchanger effectivity with the increasing of the air flow rate at different coolant flow rate were obtained using CFD method. Good agreement is found by comparing the simulation values with the test data and the deviation is less than 7% which indicate simulation model validation and research method feasibility used in this study. The simulation results indicate that bigger coolant flow rate and temperature result in higher outlet air temperature and the amount of heat transferred. The variation of the heat exchanger effectivity is predicted for different working conditions. Based on the Taguchi method, the influence of structural parameters of the corrugated fins on the heat transfer and pressure drop of the radiator is analyzed qualitatively. It is shown that fin length has the greatest impact on the comprehensive heat transfer performance of the radiator. This research provides a guide for optimizing the air preheating system and improving the amount of heat transferred. 相似文献