共查询到20条相似文献,搜索用时 78 毫秒
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根据已有研究,回热器长度100 mm的脉管制冷机在温度低于60 K时的性能较好。将一台已有的65 mm长回热器单级同轴型脉管制冷机改造为100 mm长回热器单机同轴型脉管制冷机,分析回热器长度对脉管制冷机性能的影响。基于REGEN软件对脉管制冷机回热器进行优化设计,通过改变回热器填料、压比、冷端相位角和充气压力,研究其对回热器性能的影响。在实验中进一步探索研究输入功、频率等对制冷机的最低制冷温度和比卡诺效率的影响。实验结果表明,在充气压力2 MPa,运行频率51 Hz,输入功809 W,制冷量60 W时,冷头温度109 K,制冷机的相对卡诺效率达到12.9%。 相似文献
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基于REGEN3.3软件对10 W@80 K单级高频脉冲管制冷机回热器进行了仿真计算,分析了回热器冷端相位特性对于制冷量、效率的影响及冷、热端相位特性之间的关系。研究表明:当冷端质量流幅值及压比变化时,效率最优时所对应的冷端相位角变化较小;冷端质量流幅值越大,效率最优时所对应的冷端压力波幅值也越大。回热器热端质量流幅值随着冷端质量流落后于压力波角度的减小而增加,随着冷端压比的增加而增加;热端压力波幅值随着冷端压比的增加而大幅增加;热端相位角随着冷端质量流幅值的增加而减小,随着冷端压比的增加而增加。基于研究结果总结了高频脉冲管制冷机回热器相位特性的优化方法。 相似文献
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Energy separation performance of vortex tube can be improved by using a divergent hot tube. Experiments are carried out to investigate the influence of the geometrical parameters on vortex tube refrigeration capacity by using nitrogen as the working fluid. In this work, the parameters are focused on the divergence angle of hot tube, length of divergent hot tube and number of nozzle intakes. Experimental results present that there is an optimum angle for obtaining the highest refrigeration performance, and 4° is the optimal candidate under our experimental conditions. Divergent tube length which exceeds a critical length has slight effect on the refrigeration capacity. The critical length to diameter ratio is L/D = 12 in our experiment. Increasing number of nozzle intakes increases the sensitivity of temperature reduction and can obtain the highest possible temperature reduction. Moreover, similarity relations for the prediction of the cold exit stream are presented and confirmed by the experimental data. 相似文献
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It is well known that the pressure wave should lead the volume flow rate at the ambient end of the pulse tube for a high-efficiency operation of a pulse tube cooler. Inertance tube can provide such a phase relationship without DC flow problem. However, inertance tube is always connected with a reservoir in previous literatures. Through theoretical calculation here, inertance tube without a reservoir can also provide a rather large phase-leading effect. Thus phasor diagram is used to analyze the relationship between phase-leading requirement and the pulse tube geometry. Roughly speaking, a larger void volume of pulse tube would require a larger phase-leading effect. Comparison experiments are also done on a thermoacoustically-driven pulse tube cooler. With i.d.2 mm tube as inertance tube, the tube without reservoir yields close results in terms of lowest temperature to that of the tube with reservoir and both give much better performance than that of an orifice with reservoir. Finally, the advantages of using inertance tube without reservoir are given. 相似文献
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龚汉勇 《制冷与空调(北京)》2013,(1):92-95,105
为了研究与套管式换热器连接的不同管型单根铜管的换热性能,测试密封水的温度变化过程。试验结果表明,内螺纹管的换热性能优于光面管的,前者的换热效率约为后者的2~3倍。因此推断汽车空调管片式热交换器采用内螺纹铝管替代光面铝管是具有可行性的。 相似文献
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采用实验方法,对比分析采用7mm的内螺纹管和光管冷凝器对冷冻系统整机性能的影响。测试结果表明,采用内螺纹管的冷凝器,冷凝温度降低1K,压损增大30%,功率减小1.5%,换热量增大2.5%,能效比增加3.3%。 相似文献
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An integration formula of enthalpy flow rate along a pulse tube in pulse tube refrigerators is described on the assumption of sinusoidal mass flow rate and sinusoidal pressure fluctuation. For ideal double inlet and ideal orifice pulse tube with helium as working medium, it is simplified to a polynomial formula. Polynomial formulas for roughly evaluating the volume of the pulse tube in ideal double inlet and ideal orifice pulse tube refrigerators are also given. 相似文献
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Two standing-wave thermoacoustic engines with a constant-diameter resonant tube and a tapered one, respectively, are simulated with linear thermoacoustics to explore the reasons for performance improvement of the thermoacoustic engine with the tapered resonant tube substituting for the constant-diameter one. Computed results indicate that the viscous loss in the tapered resonant tube is much lower than that in the constant-diameter one, and the smooth joint between the tapered resonant tube and its resonant cavity may avoid the acoustic power loss derived from sharp variation of flow area. The comparison between the computed results and the experimental data indicates that the simulation can roughly predict the performance of thermoacoustic engines with these two types of resonant tubes. 相似文献
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涡流管具有结构简单、无运动部件、价格低廉、可靠性高等优点,但管内发生的能量转换却极为复杂。本文以压缩空气为工作介质,对涡流管能量分离特性进行试验研究,获得涡流管制冷、制热效应随热端管长度、冷端流率之间的关系。研究结果表明,热端管长度越长,六流道喷嘴涡流管的制冷、制热效应越好,获得最大制冷效应时的冷端流率越大。 相似文献
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In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator’s orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled. 相似文献