高温高压旋风分离器流场模拟及性能试验

提出一种圆形径向进口、筒体段扩径的拱顶旋风分离器新结构;并与PV型分离器进行了流场和分离性能对比。结果表明:在相同处理气量下,新型分离器外旋流区切向速度显著大于PV型,中心涡核区轴向速度小于PV型;用中位粒径为9μm的滑石粉进行冷模试验,新型旋风分离器分离效率比PV型高约1%;新型旋风分离器结构强度和分离性能优良,适合高温、高压的工况下应用。     

Investigation of the parameters of a vortex flow inside a Ranque-Hilsch tube

Experimental data are presented on the parameters of a vortex flow, measured along a Ranque-Hilsch tube in adiabatic and nonadiabatic conditions. Graphs are given showing the variation of the thickness of the external stream, the temperature, and the heat transfer coefficient along the tube.     

Experimental investigation of performance of hot cascade type Ranque-Hilsch vortex tube and exergy analysis

In this study, three Ranque-Hilsch vortex tubes were used, which have 9 mm inside diameter and length/diameter ratio was 15. Their performances were examined as one of the classical RHVT and other was hot cascade type RHVT. Performance analysis was according to temperature difference between the hot outlet and the inlet (ΔT_hot.). The ΔT_hot values of hot cascade type Ranque-Hilsch vortex tubes were greater than the ΔT_hot values of classical RHVT, which were determined experimentally. The total inlet exergy, total outlet exergy, total lost exergy and exergy efficiency of hot stream were investigated by using experimental data. In both the classical RHVT and hot cascade type RHVT, it was found that as fraction of cold flow increases the total lost exergy decreases. It was also found that, the hot cascade type RHVT more exergy efficiency of hot outlet than the classical RHVT. Excess ΔT_hot value of hot cascade type Ranque-Hilsch vortex tube causes the excess exergy efficiency of hot outlet.     

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.     

喷射沉积过程中气体流动特征的试验研究

对喷射沉积过程中气体流动的动力学特征进行的试验研究结果表明，气体的轴向速度随雾化压力的增加而增大，并在一定压力下具有极大值，随着Ｐｉｔｏｔ管压力测测针位置与雾化器之间距离的增加，气体速度按幂九规律衰减，在距离开喷嘴较近的位置，径向气体速度减较快，分别采用氮气和氩气雾化时，气体速度表现出类似的轴向和径向变化规律，沉积器的位置对气体流场不产生显著的影响。     

Experimental research of Stirling type pulse tube refrigerator with an active phase control

A Stirling type pulse tube refrigerator with an active phase control has been experimentally investigated. A phase shifter, which controls the phase angle between the mass flow and the pressure inside a pulse tube, plays a key roll in the performance of pulse tube refrigerators. In this study, an electrically driven and mechanically damped linear compressor, which is directly connected at the warm end of the pulse tube using a connecting tube, is used as the active phase controller (APC). Therefore, this active phase control pulse tube refrigerator (APCPTR) has no reservoir. Amplified electric signals of a function generator are supplied to both the main linear compressor, which is used as the pressure wave generator (PWG), and the APC. The type of these two linear compressors is a dual-opposed piston. The advantage of this phase sifter is easy to control the electric input power and the phase angle between the PWG and the APC. In order to clarify the characteristics of the APCPTR, the cold end temperature and the gas pressure have been measured.     

新型气源气相起爆系统实验研究

选择液化石油气加氧气为气相起爆系统新型混合气源，对其在细长管道内传爆性质进行实验研究。结果表明，新气源在内径３ｍｍ长度５００ｍ的细长塑料管道内，经激爆形成的爆轰波传爆可靠，爆速达２５００ｍ／ｓ，其尾部能可靠激爆多根分叉导爆管；爆轰淬熄直径为０７ｍｍ。气相起爆器采用气体配比、混合、反射增压、防爆等装置的系统设计是可行的。     

Dynamic Remanent Vortices in Superfluid 3He-B

We investigate the decay of vortices in a rotating cylindrical sample of ³He-B, after rotation has been stopped. With decreasing temperature vortex annihilation slows down as the damping in vortex motion, the mutual friction dissipation α(T), decreases almost exponentially. Remanent vortices then survive for increasingly long periods, while they move towards annihilation in zero applied flow. After a waiting period Δt at zero flow, rotation is reapplied and the remnants evolve to rectilinear vortices. By counting these lines, we measure at temperatures above the transition to turbulence ∼0.6 T _c the number of remnants as a function of α(T) and Δt. At temperatures below the transition to turbulence T≲0.55 T _c, remnants expanding in applied flow become unstable and generate in a turbulent burst the equilibrium number of vortices. Here we measure the onset temperature T _on of turbulence as a function of Δt, applied flow velocity v=v _n−v _s, and length of sample L.     

高温高固气质量比条件下旋风预热器换热管压降的研究

为了掌握旋风预热器换热管压降随温度、风速和固气质量比的变化规律,在各种不同条件下,对旋风预热器换热管压降进行测试。结果表明:在气流速度固定不变的情况下,当固气质量比z≤1时,随着温度的升高,压降先增大后减小,在200℃附近出现高点;当固气质量比z≥1.5时,随着温度的升高,压降逐渐减小,在600℃附近趋于平缓,之后随着温度的升高略有增大。压降总是随着风速的提高而增大,随着固气质量比的增加而增大。     

Numerical investigation of gas species and energy separation in the Ranque-Hilsch vortex tube using real gas model

A three dimensional Computational Fluid Dynamics (CFD) model is used to investigate the phenomena of energy and species separation in a vortex tube (VT) with compressed air at normal atmospheric temperature and cryogenic temperature as the working fluid. In this work the NIST real gas model is used for the first time to accurately compute the thermodynamic and transport properties of air inside the VT. CFD simulations are carried out using the perfect gas law as well. The computed performance curves (hot and cold outlet temperatures versus hot outlet mass fraction) at normal atmospheric temperature obtained with both the real gas model and the perfect gas law are compared with the experimental results. The separation of air into its main components, i.e. oxygen and nitrogen is observed, although the separation effect is very small. The magnitudes of both the energy separation and the species separation at cryogenic temperature were found to be smaller than those at normal atmospheric temperature.     

基于横纹管氨水溶液垂直管外降膜吸收性能的变化规律

针对三根不同尺寸规格的横纹管,通过实验研究提高其吸收效率,选择吸收性能最优的管型。实验结果表明,随着压差和管内冷却水流速的增大,溶液吸收氨气的量增加,管外溶液传质系数增大。当管外氨水溶液喷淋密度从小变大时,光滑管和横纹管的传质系数均先增加后减小,过程中出现了最大值。该系列实验的结果表明横纹管比相同工况的光滑管有更高的强化传热和传质能力,当溶液喷淋密度为479.6kg/(m?h)时,横纹管比光滑管的传质系数增大了97.8%。三组实验中均发现一个共同的规律,横纹管的传质系数随凹槽尺寸变化而改变,2号横纹管表现出更强的吸收氨气能力。该管凹槽宽度与横纹管外径的比值为0.0814。通过对凹槽内溶液流动模型分析,比较了溶液通过凹槽时掺混和涡流的流动形态,得出了不同尺寸规格横纹管吸收性能差异的一个原因。     

Numerical investigation of gas-particle hydrodynamics in a vortex chamber fluidized bed

Gas-particle hydrodynamic behaviour inside a vortex chamber fluidized bed is studied numerically with respect to different design and operating conditions. A three-dimensional computational fluid dynamics (CFD) model of a cylindrical vortex chamber is developed. Simulations are carried out with particles and without particles. In order to understand the gas-particle flow behavior velocity distribution, particle volume fraction distribution, radial pressure distribution and axial pressure distribution inside the vortex chamber are analyzed in detail. Particles of different diameters are used and its effect on the gas-particle flow behaviour is studied. Design parameters like the number of gas inlet slots and slot width are varied and their impact on the hydrodynamics of the vortex chamber is investigated. The numerical model is validated by comparing the numerical results with experimental results reported in literature.     

水平内螺纹管内R410A流动凝结换热的实验研究

本文实验研究了R410A在水平内螺纹管内的流动凝结换热特性,分析了水力工况、测试管结构参数对管内制冷剂侧表面传热系数、压降的影响。结果表明:表面传热系数、压降均随着质量流速的增加、冷凝温度的降低而增大;虽然表面传热系数随着测试水Re的增加而减小,但测试水Re对压降的影响很小。利用单位压降表面传热系数对换热进行综合性能评价时发现,单位压降表面传热系数随着质量流速的增加而减小,随着冷凝温度的增大而增大。将实验数据与经典关联式的预测值进行对比,对于光滑管,除了Akers et al.关联式低估了实验数据,Shah关联式与Thome et al.关联式均高估了实验数据,并且Thome et al.关联式表现出最高的预测精度。而对于内螺纹强化管,Cavallini et al.关联式展现出最高的预测精度,而Koyama et al.关联式与Miyara et al.关联式均低估了实验数据。     

1.2 Measuring technique for partial hydrogen pressures in nitrogen-neon atmospheres

Gaseous impurities inside the discharge tube of a high pressure metal iodide lamp can have a large influence on the electrical and radiation properties of the lamp. Since the main gaseous impurity is hydrogen this gas must be eliminated from the discharge tube. One way of eliminating this gas is to use a hydrogen gettering material inside the outer bulb of the lamp since, under operational conditions hydrogen can diffuse through the quartz wall of the discharge tube into the outerr bulb.Because most types of high pressure metal iodide lamps have a mixture of a noble gas and nitrogen inside the outer bulb the gettering material must react only with the hydrogen and not with the nitrogen. For this reason the qetter has to be selective. In order to invistigate the selective gettering action of different chemical compounds a simple measuring technique was used to measure continuosly the hydrogen partial pressure inside the nitrogen-noble gas atmosphere.Most investigators use a mass-spectrometer or a gas chromatograph to register the change of the partial hydrogen pressure during the lifetime of the lamp. A much better technique is the use of a nickel diffusion leak combined with a manometer. A higher accuracy can be reached with this methods and it is possible to add or pump away thhe hydrogen without changig the nitrogen or noble gas atmosphere.The selective gettering action of a ZrAl alloys has been examined by this measuring technique and the results of this investigation are given.     

Hydraulic Characteristics of Ranque-Hilsch Energy Separators

The hydraulic characteristics of an intensely swirling flow in the energy separation chambers in Ranque-Hilsch vortex tubes are investigated analytically and experimentally. Computer codes are developed and realized numerically for the calculation of the aggregate coefficient of hydraulic drag under conditions of swirling flow in an axisymmetric channel of a vortex tube. The results are treated in the form of criteria equations for the calculation of coefficients of hydraulic drag as functions of the basic process and geometric parameters of the vortex tube. The vortex tube hydraulics are studied experimentally, and the results of calculations performed using our procedure are compared with the data of numerical calculation using the commercially available CFX-TASCFlow package and with experimental data. Adequate agreement is observed between the experimentally obtained and numerical calculation results.     

Comparison of CFD analysis to empirical data in a commercial vortex tube

This paper presents a comparison between the performance predicted by a computational fluid dynamic (CFD) model and experimental measurements taken using a commercially available vortex tube. Specifically, the measured exit temperatures into and out of the vortex tube are compared with the CFD model. The data and the model are both verified using global mass and energy balances. The CFD model is a two-dimensional (2D) steady axisymmetric model (with swirl) that utilizes both the standard and renormalization group (RNG) k-epsilon turbulence models. While CFD has been used previously to understand the fluid behavior internal to the vortex tube, it has not been applied as a predictive model of the vortex tube in order to develop a design tool that can be used with confidence over a range of operating conditions and geometries. The objective of this paper is the demonstration of the successful use of CFD in this regard, thereby providing a powerful tool that can be used to optimize vortex tube design as well as assess its utility in the context of new applications.     

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。     

Energy separation mechanism in unconfined laminar compressible vortex

A theoretical investigation from the view point of gas-dynamics and thermodynamics was carried out, in order to clarify the energy separation mechanism in an unconfined laminar compressible vortex, as a primary flow element of a vortex tube. The mathematical solutions of density and temperature in a viscous compressible vortical flow, with tangential velocity, were examined using an evaluation equation of total temperature. It is found from the results that a hotter gas in the peripheral region of the vortex is mainly generated by heat caused by viscous dissipation. A colder gas in the vortex center is mainly generated by viscous shear work done by the fluid element onto the surface of the surrounding gas. In addition, it is also found that the larger the representative Mach number of a vortex is, the lower the total temperature at the center of the vortex is, and at the same time, the higher the maximum total temperature in the peripheral region is. The increase in specific heat ratio of the working gas has the same effect, as increasing the representative Mach number of the vortex, on the total temperature in the vortex.