带排液结构的涡流管的性能实验

设计了带排液结构的涡流管的基本结构并搭建了性能研究实验平台,以空气为介质,研究长径比、排液口位置、排液间隙、可凝组分浓度对涡流管性能的影响。实验结果表明:在实验所进行的冷流率范围内,制热效应随着冷流率的增加而逐渐增大,制冷效应则存在极大值;随着长径比的增加,温度效率的极值有所增大,但是当长径比达到一定的数值后,温度效率和制冷效率增加的幅度显著减小;排液口位置的改变对于涡流管温度效率和湿气脱除率的影响不大;排液间隙的存在对涡流管的冷热分离性能有影响,间隙为1 mm时湿气脱除率最小;随着可凝组分浓度的增加,湿气脱除率逐渐增大,但增大的趋势逐渐趋于平缓。     

热端管长度对涡流管性能影响的实验研究

研制了不同热端管长度的涡流管,并以空气作为工作介质,通过实验研究了热端管长度对涡流管能量分离性能的影响.实验结果表明:对于常温涡流管,在入口压力为0.5MPa的情况下,相同冷流率时,随着热端管长度的增加,涡流管的制冷温度效应、单位制冷量和制冷系数增加,而其制热温度效应无显著的规律;对同一热端管长的涡流管,随着冷流率的增加,涡流管的制冷温度效应、单位制冷量和制冷系数增加,且在冷流率为40%～50%时出现峰值,而制热温度效应随冷流率的增加而增加,在冷流率范围内未出现峰值.     

涡流管的入口压力对其性能影响的研究北大核心CSCD

针对涡流管的性能优化问题,需要研究各个参数及结构部件对其制冷、制热能力的影响,并寻求最佳的运行工况。本文搭建了开式实验系统,采用自制的六流道喷嘴,以二氧化碳气体为工质,研究了入口压力和冷流率对涡流管能量分离性能的影响。结果表明:涡流管的制冷、制热效应均随入口压力的增大呈现先增大后减小的趋势,在入口压力为0.4 MPa,冷流率为0.4时具有最佳制冷效应,冷流率为0.9时,具有最佳制热效应;冷流率为0.2~0.5时,涡流管热端管壁面温度随冷流率的增大呈现逐渐升高的趋势,冷流率为0.6~0.9时,壁面温度在出现壁面最高温度点后有所下降,并且冷流率越大壁面温度下降越明显。     

冷孔板孔径及进口压力对涡流管性能影响的实验研究北大核心CSCD

针对涡流管大量应用于制冷系统中,对涡流管的各项参数进行研究,寻求最佳制冷工况及参数。本文自行设计涡流管实验样机,搭建开式的涡流管实验台,以CO2为工质,在不同的进口压力(0.2~0.6 MPa)、不同的冷流率(0.2~0.9)工况下研究了5种冷孔板孔径(1.5~3.5 mm)的涡流管性能,分析冷孔板孔径对涡流管性能的影响情况。研究表明:制冷、制热效应均在0.4MPa达到峰值后出现下降,在冷孔板孔径为2.5 mm时获得最佳制冷效应29.3℃、制热温度效应37.9℃,且获得最佳制冷量及制冷性能。     

冷孔板孔径及进口压力对涡流管性能影响的实验研究北大核心CSCD

针对涡流管大量应用于制冷系统中,对涡流管的各项参数进行研究,寻求最佳制冷工况及参数。本文自行设计涡流管实验样机,搭建开式的涡流管实验台,以CO2为工质,在不同的进口压力(0.2~0.6 MPa)、不同的冷流率(0.2~0.9)工况下研究了5种冷孔板孔径(1.5~3.5 mm)的涡流管性能,分析冷孔板孔径对涡流管性能的影响情况。研究表明:制冷、制热效应均在0.4MPa达到峰值后出现下降,在冷孔板孔径为2.5 mm时获得最佳制冷效应29.3℃、制热温度效应37.9℃,且获得最佳制冷量及制冷性能。     

进气温度与压力对锥形涡流管性能的影响

以氮气为工质,对锥形涡流管能量分离特性进行了实验研究,结果表明入口气流温度对锥形涡流管的工作性能影响较小.进气压力越高,能量分离性能越强,不同压力下都在冷气流率约0.2时,可得到最大制冷效应和制冷效率,冷气流率约为0.5时,可获得最大制热效应.升高压力可提高锥形涡流管的能量分离性能,但提高幅度逐渐减小,当压力升高到一定...     

六流道喷嘴涡流管能量分离特性的研究

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。以压缩空气为工作介质，对涡流管能量分离特性进行了实验研究，获得了涡流管制冷、制热效应随入口压力、冷端流率之间的关系，研究结果表明，进口压力越高，六流道喷嘴涡流管的制冷、制热效应越好，但获得最大制冷、制热效应时的冷端流率均有减小的趋势。     

工业机柜涡流管制冷装置性能试验研究

介绍了工业机柜涡流管制冷装置试验台;对实验结果进行了分析,分析表明,涡流管的入口温度越低,其制冷性能越好,制热性能越差,对涡流管的分离效应影响不大;涡流管的入口压力越高,涡流管表现出更好的制冷性能、制冷效应、制热性能和制热效应,其分离效应也增强;热阀开度K=1时,涡流管有最好的制冷性能和制冷效应;热阀开度K=2时,涡流管有最好的制热性能和制热效应;热阀开度K=1和K=2时都有较高的分离效应.     

热端管长度对涡流管性能影响的试验研究

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。     

冷孔板直径与冷流率对涡流管流场的影响

以理想二氧化碳气体为工质,采用Standard k-ε湍流模型,对涡流管能量分离效应进行数值模拟。在此基础上,探究涡流管轴向、切向速度分布以及冷孔板直径与冷流率之间的关系。模拟结果表明:当进口温度为298.15 K、进口压力为6.5 MPa、冷流率μ为0.1—0.9、冷孔板直径R在1.5—3.5 mm范围变化时,随着冷孔板直径的增大,轴向速度逐渐增大,切向速度逐渐减小;制冷温度效应呈现先增大后减小的趋势、随着冷流率的增大,冷热流分界面逐渐增大,制冷温度效应呈现逐渐减小的趋势。     

Experimental investigation of vortex tube refrigerator with a divergent hot tube

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.     

冷端孔径对涡流管性能影响的实验研究

本文搭建了涡流管性能实验台,研究了不同冷端孔口直径的涡流管实验样机的性能。当进口压力为0.3~0.5 MPa时,分析了冷端孔径对冷端温降特性、制冷量特性、等熵温度效率特性及COP特性的影响。结果表明:冷端孔口直径对涡流管性能有很大影响,存在一个使涡流管冷端温降及制冷量均达到最大值的最佳冷端孔口直径,在本文设计的涡流管几何尺寸条件下,最佳冷端孔口直径为5 mm,最佳冷端孔口直径与热端直径比为0.5。     

Modification and experimental research on vortex tube

Vortex tube (VT) is a simple energy separating device which is compact and simple to produce and to operate. Although intensive research has been carried out in many countries over the years, the efficiency is still low. In order to improve the energy separate efficiency of vortex tubes, three innovative technologies were applied to vortex tubes. A new nozzle with equal gradient of Mach number and a new intake flow passage of nozzles with equal flow velocity were designed and developed to reduce the flow loss. A new kind of diffuser invented by us was installed for reducing friction loss of air flow energy at the end of the hot end tube of vortex tube, which can greatly improve the performance of vortex tube. The experiment results indicated that these modifications could remarkably improve the performance of vortex tube. The developed vortex tube was not only superior to the conventional vortex tube but also superior to that made by two companies in world under big cold gas mass flow ratio.     

Parametric and internal study of the vortex tube using a CFD model

A computational fluid dynamics (CFD) model is used to investigate the energy separation mechanism and flow phenomena within a counter-flow vortex tube. A two-dimensional axi-symmetric CFD model has been developed that exhibits the general behavior expected from a vortex tube. The model results are compared to experimental data obtained from a laboratory vortex tube operated with room temperature compressed air. The CFD model is subsequently used to investigate the internal thermal-fluid processes that are responsible for the vortex tube's temperature separation behavior. The model shows that the vortex tube flow field can be divided into three regions that correspond to: flow that will eventually leave through the hot exit (hot flow region), flow that will eventually leave through the cold exit (cold flow region), and flow that is entrained within the device (re-circulating region). The underlying physical processes are studied by calculating the heat and work transfers through control surfaces defined by the streamlines that separate these regions. It was found that the energy separation exhibited by the vortex tube can be primarily explained by a work transfer caused by a torque produced by viscous shear acting on a rotating control surface that separates the cold flow region and the hot flow region. This work transfer is from the cold region to the hot region whereas the net heat transfer flows in the opposite direction and therefore tends to reduce the temperature separation effect. A parametric study of the effect of varying the diameter and length of the vortex tube is also presented.     

涡流板制冷特性的实验研究

引进集成整合的观念,研制成新的制冷装置（即涡流板）,并利用涡流板制冷实验系统,以压缩空气为介质,对涡流板的制冷特性进行实验研究,获得了涡流板的制冷性能参数与入口气流参数及冷流比之间的关系。研究结果表明：涡流板同单管涡流管相比具有相同的制冷,洼能,为涡流板进一步研究奠定了基础。     

导叶式旋风管内短路流颗粒夹带的研究

采用数值模拟方法,结合试验与理论分析,研究Shell型导叶式旋风管内短路流颗粒夹带问题。结果表明:Shell型旋风管直筒芯管下口存在短路流现象,计算得知短路流量占进口总流量的39.3%。理论分析发现,短路流主要夹带粒径小于9μm的颗粒,短路流夹带颗粒临界粒径为9μm。另外,数值模拟跟踪颗粒逃逸的轨迹证明,Shell型旋风管能将粒径大于9μm的颗粒全部除尽;粒径小于9μm的颗粒既有经排尘口返混逃逸,又有短路流夹带逃逸,其中短路流夹带逃逸占主要部分,且随着粒径的增加,经芯管下口短路夹带逃逸的数目减小。     

蒸发盘管内制冷剂喷射蒸发的制冷系统研究

制冷剂高压能的利用对改善制冷系统运行有重要意义。基于场协同理论,提出了一种利用制冷剂在蒸发管内进行喷射的新型制冷系统,理论上分析了协同角随毛细管管径和喷射孔直径的变化规律,并进行了相关的可视化实验。理论分析结果表明:协同角随着喷射孔直径的增大而增大;随着毛细管管径的减小而减小,但是随之减小的速率降低。实验结果表明:和传统的毛细管节流制冷系统相比,开孔实验的制冷剂的充注量减少70%以上,COP提高了9%,系统达到稳定的时间减少了70%。