共查询到18条相似文献,搜索用时 437 毫秒
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为进一步研究降低20 K温区单级斯特林型脉管制冷机关键部件中损失的方法,提高整机性能,采用计算软件Sage对制冷机进行模拟。通过实验结果与Sage计算的对比对模拟程序的有效性进行了考察,并从调相系统结构及水冷器结构方面寻找优化途径。结果表明,在单纯使用惯性管气库调相时,计算最低制冷温度比实验值低9 K左右;当采用双向进气与惯性管调相组合时,计算同实验结果基本一致。最后引入虚拟的振子阻尼调相机构对制冷机的最佳性能进行研究,计算表明在这种调相结构下,制冷机的无负荷制冷温度及30 K时的制冷量均可以得到比双向进气加惯性管组合调相更优的结果。 相似文献
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考虑到现有的热耦合双级脉管制冷机在第二级上存在效率低、冷量小等问题,对一种大功率脉管制冷机的第二级(视为整机)进行了单独的模拟和实验研究。模拟结果表明在回热器直径为55 mm的冷头设计下惯性管调相能力足够,减短惯性管长度或增大惯性管直径可有效改善回热器相位,并可通过调节工作频率使回热器相位达到理想状态。实验结果表明当惯性管长度为3 m,直径为10 mm,运行频率为58 Hz,工作电压为240 V时,获得47.8 K无负荷制冷温度,在输入功为777 W时,于129.3 K得到60 W制冷量,比卡诺效率为10.27%。因此,第二级具有较好的制冷性能。 相似文献
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研制了一台低于40 K温区的单级同轴型高频脉冲管制冷机,采用多路旁通结构,在输入功率为222 W时,其最低温度达到34.22 K,并比较了惯性管、惯性管加双向进气、惯性管加多路旁通以及惯性管加双向进气加多路旁通4种固定调相装置的差异(其中双向进气采用喷嘴结构).实验结果表明:惯性管、喷嘴、多路旁通组合方式是一种非常有效的降低制冷温度的方式,是应用深低温区单级脉冲管制冷机调相方式的最佳选择;而惯性管则是应用于较高温区大冷量的最佳的调相方式.实验还表明,多路旁通加喷嘴结构能够降低脉冲管内部的直流,有效地提高脉冲管制冷机的性能. 相似文献
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对内调相型脉管制冷机进行热力学理论分析.内调相型脉管制冷机的特点是两个冷头在脉管热端通过针阀串联,两边脉管内的压力和流量耦合,通过调节各自的输入压力相位来主动调节脉管冷端流量与压力的相位差,输入压力相位由一个具有双出口的旋转阀来实现.分析表明,该调相方法可使脉管冷端流量与压力同相,从而使制冷量最大,而且相比于传统的小孔加气库型和双向进气型脉管制冷机,其制冷效率大大提高.该结构省却了体积较大的气库,结构更加紧凑. 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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《低温学》2016
Stirling type pulse tubes are classically based on the use of an inertance phase shifter to optimize their cooling power. The limitations of the phase shifting capabilities of these inertances have been pointed out in various studies. These limitations are particularly critical for low temperature operation, typically below about 50 K. An innovative phase shifter using an inertance tube filled with liquid, or fluid with high density or low viscosity, and separated by a sealed metallic diaphragm has been conceived and tested. This device has been characterized and validated on a dedicated test bench. Operation on a 50–80 K pulse tube cooler and on a low temperature (below 8 K) pulse tube cooler have been demonstrated and have validated the device in operation. These developments open the door for efficient and compact low temperature Stirling type pulse tube coolers. The possibility of long life operation has been experimentally verified and a design for space applications is proposed. 相似文献
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《低温学》2018
The inertance tube plays a significant role in improving the performance of the Stirling type pulse tube cryocooler by providing the desired phase angle between the mass flow and pressure wave. The phase angle is highly depended on the inertance tube geometry, such as diameter and length. A cylindrical threaded root device with variable thread depth on the outer screw and inner screw creates an adjustable inertance tube whose diameter and length can be adjusted in the real time. However, due to its geometry imperfectness, the performance of this threaded inertance tube is reduced by the leaks through the roots between the two screws. Its phase angle shift ability is decreased by 30% with the leakage clearance thickness of 15.5 μm according to both the theoretical prediction and the experimental verification. 相似文献
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A three-stage Stirling pulse tube cryocooler operating below the critical point of helium-4 总被引:1,自引:0,他引:1
Precooled phase shifters can significantly enhance the phase shift effect and further improve the performance of pulse tube cryocoolers. A separate three-stage Stirling pulse tube cryocooler (SPTC) with a cold inertance tube was designed and fabricated. Helium-4 instead of the rare helium-3 was used as the working fluid. The cryocooler reached a bottom temperature of 4.97 K with a net cooling power of 25 mW at 6.0 K. The operating frequency was 29.9 Hz and the charging pressure was 0.91 MPa. It is the first time a refrigeration temperature below the critical point of helium-4 was obtained in a three-stage Stirling pulse tube cryocooler. 相似文献
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《低温学》2016
This paper presents experimental results on a novel two-stage gas-coupled VM-PT cryocooler, which is a one-stage VM cooler coupled a pulse tube cooler. In order to reach temperatures below the critical point of helium-4, a one-stage coaxial pulse tube cryocooler was gas-coupled on the cold end of the former VM cryocooler. The low temperature inertance tube and room temperature gas reservoir were used as phase shifters. The influence of room temperature double-inlet was first investigated, and the results showed that it added excessive heat loss. Then the inertance tube, regenerator and the length of the pulse tube were researched experimentally. Especially, the DC flow, whose function is similar to the double-orifice, was experimentally studied, and shown to contribute about 0.2 K for the no-load temperature. The minimum no-load temperature of 4.4 K was obtained with a pressure ratio near 1.5, working frequency of 2.2 Hz, and average pressure of 1.73 MPa. 相似文献
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双向进气型脉管制冷机的线性理论分析 总被引:1,自引:0,他引:1
采用线性模型对双向进气型脉管制冷机的性能进行了分析.得到了通过回热器的焓流、质量流量及脉管冷端压力和流量相位差的代数计算公式.详细分析了工作频率对脉管制冷机制冷量与COP的影响,并对额定输入压力振幅和额定输入功率两种工况分别进行了优化分析.所得结果与其它文献完全一致. 相似文献
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A nodal analysis method for simulating inertance tube pulse tube refrigerators is introduced. The energy equation, continuity equation, momentum equation of gas, energy equation of solid are included in this model. Boundary condition can be easily changed to enable the numerical program calculate thermal acoustic engines, inertance tube pulse tube refrigerators, double inlet pulse tube refrigerators, and others. Implicit control volume method is used to solve these equations. In order to increase the calculation speed, the continuity equation is changed to pressure equation with ideal gas assumption, and merged with momentum equation. Then the algebraic equation group from continuity and momentum equation becomes one group. With this numerical method, an example calculation of a large scale inertance tube pulse tube refrigerator is shown. 相似文献