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新型叠片式油冷却器传热及综合性能的研究 总被引:1,自引:0,他引:1
探讨一种铝叠片和弓形折流板相结合的新型叠片式油冷却器,对其传热及综合性能进行了研究,并与螺纹管弓形折流板油冷却器进行了对比.试验结果表明,新型叠片式油冷却器热交换量较螺纹管弓形折流板油冷却器平均提高52.5%,单位压降热交换量较螺纹管弓形折流板油冷却器平均提高24.1%.在整体结构方面,其单位体积换热面积为螺纹管弓形折流板油冷却器的2.84倍,而材料总重量仅为螺纹管弓形折流板油冷却器的60.7%,说明新型叠片式油冷却器具有体积小、换热面积大、重量轻的优点;从经济效益角度看,新型叠片式油冷却器相比螺纹管弓形折流板油冷却器更加节省耗材成本,体现了新型换热器的高效性、紧凑性和节能性. 相似文献
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大小孔折流板与圆弧波纹管都是近几年提出的降低换热器壳程压降和提高传热效果的结构元件。针对大小孔折流板和圆弧波纹管的特点,提出了将两者相结合的低压降高效换热器,并试验研究该换热器的流动和传热性能。结果表明,换热器具有较低的壳程压降和良好综合传热能力。与光管的普通弓形折流板换热器相比,相同流量下,大孔直径为φ26mm的圆弧切线波纹管与大小孔折流板复合结构换热器的壳程板间压降可降低64%,虽然孔径较大时壳程膜传热系数有所下降,但总传热系数有明显提高。若以单位压降的传热系数来评判,圆弧切线波纹管与大小孔折流板复合结构换热器的强化传热性能要远高于普通弓形折流板换热器,最高值可达普通弓形折流板换热器的2.87倍。 相似文献
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翅片管换热器是高效节能钢带式果蔬绿色干燥装备的供热装置,通过对翅片管换热器的翅化比、对流换热系数、传热系数及阻力的计算,得到了翅片管换热器的压降及翅片管的管数,计算结果表明翅片管换热器换热能力强,传热系数高。 相似文献
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为研发数据机房空气调节用高效制冷机组的需要,设计了一种兼为冷凝蒸发器和储液器的多功能壳管式换热器。换热器的管程为蒸发侧,由数个相互独立的蒸气压缩制冷回路的蒸发管簇组成,通过启停制冷压缩机的工作数量等能量调节技术以适应热负荷的宽幅变化;壳程为冷凝侧,进入的第二制冷工质的干度或过热度随着外界环境温度及热负荷的变化在较宽的范围内波动,通过进液口、均流板和蒸发管簇,被冷凝和过冷后储存在壳管的下半部,通过液泵输送到室内侧蒸发器吸热。该换热器结构紧凑、工作可靠,可通过调节制冷系统的能量输出精确控制供液参数,并通过调节第二制冷工质的供液量快速响应被控对象热负荷变化,工程样机性能试验结果表明该换热器达到了预期设计目标。 相似文献
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介绍大直径双壳程、双管程及多管程换热器隔板槽加工中的难点及解决这一难点的思路和方法。介绍管板隔板槽加工专用铣床的结构特点、工作原理、操作要点及使用效果。 相似文献
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P. C. Mukesh Kumar J. Kumar R. Tamilarasan S. Sendhil Nathan S. Suresh 《Journal of Mechanical Science and Technology》2014,28(5):1841-1847
In this experimental investigation, the heat transfer and pressure drop analysis of a shell and helically coiled tube heat exchanger by using Al2O3 / water nanofluids have been carried out under turbulent flow condition. The Al2O3/ water nanofluids of 0.1%, 0.4%, and 0.8% particle volume concentration have been prepared by using two step method. The tube side experimental Nusselt number of 0.1%, 0.4% and 0.8% nanofluids were found to be 28%, 36% and 56%, respectively higher than water. These enhancements are due to higher thermal conductivity of nanofluid, better fluid mixing and strong secondary flow formation in coiled tube. The pressure drop of 0.1%, 0.4% and 0.8% were found to be 4%, 6%, and 9%, respectively higher than water. The increase in pressure drop is due to increase in nanofluid viscosity while adding nanoparticles. The measurement of nanofluid thermal performance factor is found to be greater than unity. It is concluded that the Al2O3 nanofluid can be applied as a coolant in helically coiled tube heat exchanger to enhance heat transfer with negligible pressure drop. 相似文献
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同轴套管式地热能开采技术是用于中深层地热能开采的有效方式。为了增强同轴套管式换热器的换热效率,提出了一种带螺旋翅片的新型同轴套管式换热器。基于有限体积法,对比分析新型与普通型同轴套管式换热器的换热性能,得到螺旋翅片结构对换热性能的影响,揭示其强化传热机理。结果表明:通过增加螺旋翅片的翅高或减小螺旋翅片的螺距,可有效增强同轴套管式换热器内流体流动的湍流动能,达到提高换热性能的目的;与普通光滑管换热器相比,翅高为19 mm,螺距为300 mm的新型换热器在雷诺数为27000时,努赛尔数提高了35.5%,摩擦系数提高了91%,热性能系数达到最高1.093;增加翅片和减小螺距都可以增加采出温度和采热功率,翅高为19 mm,螺距为300 mm换热器较光滑管换热器采热温度提高了5.4 K,采热功率提高了32.4%。为高效同轴套管式换热器设计提供了理论依据。 相似文献
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利用有限体积法对一种应用于列管式换热器壳程入口处的螺旋扰流装置进行了流体动力学计算和分析.分析结果表明:该螺旋扰流装置能够改变壳程流体入口流向,具有流阻小,减少流动死区,提高换热效率,降低管束振动等特点. 相似文献
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Ju-Won Kim Yong-Bin Im Jong-Soo Kim 《Journal of Mechanical Science and Technology》2006,20(7):1059-1067
In order to develop a compact evaporator, experiments that show characteristics of evaporating heat transfer and pressure
drop in the helically coiled minichannel were performed in our previous research. This study was focused on the performance
analysis of helically coiled heat exchangers with circular minichannels with an inner diameter=1.0 mm. The working fluid was
R-22, and the properties of R-22 were estimated using the REFPROP program. Numerical simulation was performed to compare results
with the experimental results of the helically coiled heat exchanger. As the heat transfer rate and pressure drop were calculated
at the micro segment of the branch channels, the performance of the evaporator was evaluated. The following conclusions were
obtained through the numerical simulations of the helically coiled heat exchanger. It showed good performance when the flow
rate of each branch channels was suitable to heat load of air-side. The numerical simulation value agreed with experimental
results within ± 15%. In this study, a numerical simulation program was developed to estimate the performance of a helically
coiled evaporator. And, an optimum helically coiled minichannels evaporator was designed. 相似文献
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Sang Chun Lee Sang Chul Nam Tae Gon Ban 《Journal of Mechanical Science and Technology》1998,12(5):917-925
In an effort to develop a heat transfer enhancement technique for low temperature applications such as utilization of LNG
cold energy, an experiment was carried out to evaluate the heat transfer and the pressure drop performance for a spirally
indented tube using ethylene-glycol and water solutions and pure water under horizontal single-phase conditions. The test
tube diameter was 14.86 mm and the tube length was 5.38 m. Heat transfer coefficients and friction factors for both inner
and outer surfaces of the test tube were calculated from measurements of temperatures, flowrates and pressure drops. Correlations
of heat transfer coefficients in the spirally indented tube, which were applicable for laminar and turbulent regimes were
proposed for inner, and outer surfaces. The correlations showed that heat transfer coefficients for the spirally indented
tube were much higher than those for smooth tubes, increased by more than 8 times depending upon the Reynolds number. The
correlations were compared with other correlations for various types of surface roughness. The effect of the Prandtl number
on the heat transfer characteristics was discussed. The critical Reynolds number from the laminar flow to the turbulent flow
inside the spirally indented tube was found to be around Re=1,000. 相似文献