Performance improvements of a subsonic axial-flow compressor by means of a non-axisymmetric stator hub end-wall

This paper deals with the application of a non-axisyrmnetric hub end-wall on the stator of a single stage high subsonic axial-flow compressor. In order to obtain a state-of-the-art stator non-axisymmetric hub end-wall con- figuration fulfilling the requirements for higher efficiency and total pressure ratio, an automated multi-objective optimizer was used, in conjunction with 3D-RANS-flow simulations. For the purpose of quantifying the effect of the optimal stator non axis-symmetric hub contouring on the compressor performance and its effects on the sub- sonic axial-flow compressor stator end-wall flow field structure, the coupled flow of the compressor stage with the baseline, axisymmetric and the non-axisynunetric stator hub end-wall was simulated with a state-of-the- art multi-block flow 3D CFD solver. Based on the CFD simulations, the optimal compressor hub end-wall con- figuration is expected to increase the peak efficiency by approximately 2.04 points and a slight increase of the to- tal pressure ratio. Detailed analyses of the numerical flow visualization at the hub have uncovered the different hub flow topologies between the cases with axisymmetric and non-axisymmetric hub end-walls. It was found that that the primary performance enhancement afforded by the non-axisymmelric hub end-wall is a result of the end-wall flow structure modification. Compared to the smooth wall case, the non-axisymmetric hub end-wall can reduce the formation and development of in-passage secondary flow by aerodynamic loading redistribution.     

某型低压压气机气动设计

采用以试验为基础的二元方法配之三元校算,设计出了性能优良并满足预定技术要求的某型低压压气机。全台试验结果表明,这台压气机未经调整,其流量、压比、效率已经达到了设计指标,优选工作点后性能更佳,压气机低工况性能好,有可用的稳定工作范围,出口流场均匀。     

变容量家庭能源中心单独制热水模式的实验研究

提出了可全年供应空调和热水需要的变容量家庭能源中心系统,并提出单独制热水模式下的性能系数计算方法。通过对该模式瞬时动态特性的研究,指出变容量压缩机可以有效地保证机组的安全可靠运行。实验研究了单独制热水模式在不同环境温度、不同压缩机负荷条件下的性能。结果表明,在同一压缩机负荷条件下,热水性能系数均随环境温度的升高而升高,与传统热泵热水器的变化趋势相同。而压缩机负荷变化对机组热水性能系数的影响在不同的环境温度下呈现不同的规律,因此,可根据不同的环境温度优化控制压缩机负荷,以提高制热水效率,节约能源。     

A controlled environment laboratory for the testing of domestic heat pumps

The construction and operation of a controlled-environment laboratory for the testing of domestic heat pumps is described. the operational range of the laboratory is - 5°C to 20°C with relative humidity up to 100%. Air-to-water heat pumps of up to 16 kW heating capacity can be tested with the present design, but modifications to allow for the testing of larger units or of air-to-air units are also described. the laboratory is stable to within 1°C and 5% relative humidity, and has a recovery time of 12 min to a perturbation of 3 kW. the test procedure for air-to-water heat pumps is described in detail and some preliminary results presented.     

Helical liquid ring compressor for a steam compression heat pump: I. Concept and basic running characteristics

The liquid ring compressor (LRC) is a compressor suitable for a heat pump which uses water as a working fluid. The LRC has several features: (1) large suction speed; (2) low discharge temperature realized by the ring liquid; and (3) simple structure. However, in order to enlarge the working temperature region of such heat pumps toward lower temperature levels, it is necessary to improve the volumetric efficiency of the LRC, especially in the low suction pressure region. Therefore, a helical liquid ring compressor (HLRC) which has helical blades has been newly designed, as one of the attempts to obtain a higher volumetric efficiency. The HLRC is able to separate a suction space from a compression space along the axis and improve the volumetric efficiency. An experimental test has verified that the suction/compression mechanism of the HLRC functions as expected. © 2000 Scripta Technica, Heat Trans Asian Res, 29(8): 660–673, 2000     

基于扩压因子流型的压气机快速性能预测算法

为快速、准确地获得压气机性能参数、完成压气机性能预测,实现压气机优化设计,基于流线曲率法,将扩压因子作为控制方程、损失模型、熵增修正模型及落后角模型中的关键参数,建立轴流压气机性能快速预测算法。利用该算法对某跨音速轴流压气机性能参数进行计算,并将计算结果与主流商业软件计算结果及试验数据进行对比。通过对比发现：该算法计算效率高,能够快速且较为准确地完成压气机整体性能和沿叶高方向流场参数的预测;计算范围广,在不同转速、不同流量等非设计工况下算法预测结果均与试验及数值模拟数据接近;所选取与完善的经验公式合理可靠,能够较好地描述压气机内部流动。     

大功率柴油机用新型增压器的研制

针对我国内燃机车用大功率柴油机自主开发了一种新型增压器。这种增压器采用了无水冷、高效宽流量压气机叶轮、大腔体等新结构和新技术,标定点压比为3.5~3.6,流量为4.3~4.5 kg/s,单台配机功率为2 330 kW,增压器配机总效率达到61%以上。目前,该型增压器已通过各种考核性试验,达到预期指标。文中介绍了新型涡轮增压器的结构、性能、新压气机叶轮、涡轮开发的过程和增压器的试验情况。     

氦气离心压气机高压比设计研究

氦气离心压气机是预冷发动机氦回路的核心部件,但国内对氦气离心压气机的相关探究较少。为探究氦气离心压气机的压比设计方法,从离心压气机进口和出口速度三角形的角度,分析了出口安装角、滑移因子以及进气负预旋对叶轮做功的影响。提出了基于低出口安装角、高滑移因子和进气负预旋的高压比设计方法。根据此方法设计出了总压比为2.521、等熵效率为83.2%、喘振裕度为18.55%的氦气离心压气机,并通过数值模拟的方法对此压气机的气动特性以及流场进行了分析,证明了高压比设计方法的可行性。     

An economic and technical case for a compressor/expander unit for heat pumps

Despite their obvious environmental benefit, heat pumps in general have difficulties in penetrating the heating market because of the high initial capital cost. However, given the fact that in the U.K. space heating alone accounts for nearly 50 per cent of all the primary energy used, the universal adoption of heat pump subsidies similar to those offered by certain German utilities for example would be an effective contributor to the reduction of greenhouse gas emission. However, it would be improper for subsidies alone to be the only mechanism by which heat pumps could gain the scale of market acceptance necessary in order to make the required greenhouse gas emission cuts. Therefore, a new generation of heat pumps must have a superior performance than existing units operating with HCFC R22 or R407c. The use of R410a can aid heat pump market penetration by having heat pumps of a superior performance and a smaller size. However, to make full use of R410a, the difficulties of the relatively low critical point must be overcome and the use of a novel compressor/expander unit is illustrated. Copyright © 2000 John Wiley & Sons, Ltd.     

The development of a refrigeration compressor for domestic heat pump application

An experimental investigation has been conducted of a compressor originally designed for air-conditioning applications to determine how much its performance could be improved for use in domestic heat pumps. The compressor was a hermetic unit of nominal capacity 15.6 cm³, driven by a single phase electric motor. The application selected was for heating only, air to air heat pumps. Improvements have been achieved in both coefficient of performance (13 per cent) and heat output (7 per cent), as well as in ancillary matters such as lubrication, noise and power factor.     

An empirical model for a heat pump dehumidifier drier

Data obtained from laboratory measurements on a dehumidifier using R134a in a scroll compressor are analysed to establish empirical sub-models for the principal drier components. A model for the dehumidifier system is set up by coupling the sub-models using energy and mass balances. The performance data obtained using the system mdoel is in good agreement with the measured data obtained with four system configurations under a wide range of operating conditions. The model is used to demonstrate how the performance for the dehumidifier relates to that for the coupled kiln-dehumidifier system. By resizing the heat exchangers it is shown that the energy efficiency of the prototype system can be increased significantly, the dehumidifier specific moisture extraction rate approaching 10 kgkWh⁻¹ at high humidity.     

S-CO2布雷顿循环中离心式压缩机研究现状

从小型离心式压缩机运行效率和冷凝影响两方面介绍了国内外机构对S-CO2离心式压缩机研究的现状。指出:采用小型离心式压缩机对布雷顿动力循环系统中压缩机的设计和理论研究进行实验验证仍是最优的方案;应充分利用现有技术深入研究小型离心式压缩机内部流场分布和边界层的影响,为S-CO2离心式压缩机设计与优化提供理论支持。     

舰船大功率轴流压气机气动设计研究

基于建立的舰船大功率多级轴流压气机气动设计体系,开展了舰船用某型大功率燃气轮机压气机设计研究,完成了6级轴流压气机的气动设计。进行了一维反问题设计、一维特性计算分析、S2反问题计算、叶片造型以及三维CFD计算分析。各级载荷分布从前面级到后面级逐渐降低,叶展方向按照等压比分配以避免径向掺混损失过大,S2设计并没有严格遵循传统的设计规律(等环量、等反动度等),而是基于一维设计方案通过不断调整优化获得的。根据CDA的特点,开发了可用于工程应用的叶片造型程序,可实现不同中弧线、不同厚度分布调节,能够实现叶片弯、掠等功能。三维数值模拟结果表明,考虑动叶叶顶具有0. 5 mm间隙的情况下,6级压气机设计点效率达到89. 75%,设计转速下的喘振裕度为22. 5%,同时具有较好的变工况性能。     

Vapor compression multifunctional heat pumps in China: A review of configurations and operational modes

With the growing concerns about worldwide energy and environmental sustainability, heat pump water heaters and solar water heaters became popular in China after 2000. The combinations between the heat pump air conditioner, heat pump water heater and solar water heater brought about more energy saving operational modes besides those included in the above three appliances, which promoted the development of multifunctional heat pumps. The combinations also resulted in the higher utilization ratio and lower operational cost of the heat pump, then the payback time can be shortened greatly. The rapid development of multifunctional heat pumps at the beginning of the 21st century in China indicates its promising application prospect.The heat pump air conditioner was the fundamental component of a multifunctional heat pump. Versatile configurations of multifunctional heat pumps were evolved from the integration of the domestic water heat exchanger with the refrigerant loop of the heat pump air conditioner by various approaches. This paper reviewed the development of multifunctional heat pumps in China, mainly focusing on configuration features and operational modes of the heat pump. The configuration of a multifunctional heat pump fundamentally determines the initial cost, operating cost and operating reliability. Therefore, it is reasonable to make a compromise between the simplicity of the configuration and versatile operational modes in the design of the multifunctional heat pump under different application conditions.     

压气机叶片多工况气动优化设计研究

采用数值优化方法对跨声速压气机转子叶片进行了多工况气动优化设计,并对设计前后的几何形状、总体性能及流场的变化进行了详细的分析对比。结果表明,压气机转子前缘激波后掠可以有效地降低损失。优化后叶片的变工况性能非常好。各个工况点的质量流量基本不变,并且叶片稳定工作范围有所扩大。     

关于中高温热泵试验中的几种特殊现象

在对中高温热泵进行了大量的试验研究之后，发现了四种有别于理论分析结果的试验现象，如冷凝温度下降，COP也下降；压缩机转数降低，COP降低等。针对这些特殊现象，进行了详细的描述、分析和较合理的解释，最终给出了对中高温热泵在设计和实际运行中的一些建议，这将有助于中高温热泵系统的安全高效运行。     

基于NURBS曲线的高亚音速压气机叶型参数化建模方法研究

具有良好灵活性的高精度叶型参数化建模方法对于压气机叶型设计和优化具有重要影响。本文研究了一种基于非有理B样条曲线理论(NURBS)曲线组和遗传算法的轴流压气机叶片参数化建模方法。该方法基于中弧线厚度叠加法,采用两条三次七点NURBS曲线分别构造中弧线形状和厚度分布,前尾缘采用双二次NURBS曲线,通过多段曲线光滑拼接实现叶片造型。以压气机型线方差值最小作为目标函数,利用遗传算法实现了叶型的参数化建模。通过数值模拟实验证明,本文提出的参数化造型方法适用于高亚音速压气机叶型的参数化建模。     

压缩机中间冷却器采用不锈钢波纹管的试验研究

采用新型不锈钢波纹管代替壳管式换热器中的直管,对压缩机中间冷却器进行了改造,并进行了实际运行测试和比较分析。结果表明：波纹管换热器的天然气出口温度能够达到甚至低于压缩机的设计值,换热效率比例管换热器的高61％,压缩机的操作正常平衡,维护工作最大大降低,达到长周期运行的目的。     

Dynamic and energy analysis of a liquid piston hydrogen compressor

Liquid piston compressor is the most promising compressor to be used for hydrogen-refueling stations. However, their energy transfer and the energy dissipation processes of are poorly studied and not well understood. In this paper, a new energy analysis method for an ionic-liquid type liquid piston compressor is proposed. In the compressor section, porous media is used to promote heat transfer from the hydraulic oil during the compression process. A mathematical model has been formulated considering the heat transfer and damping effects of the porous media on the compressor performance. Moreover, the compressibility of the hydraulic oil and its overflow loss on the compressor performance were also established. In the model, the seven stages of the entire working cycle of the compressor were look into in detail, alongside with its energy efficiency. The results show that the key parameters governing the energy efficiency of the compressor are the heat transfer efficiency of the compressor and the overflow losses of the hydraulic oil.     

首台国产天然气长输管线压缩机组负荷分配控制系统研究

为了在某压气站实现国产首台燃驱压缩机组与引进燃驱压缩机组联合运行,安全、高效、平稳实现多机组负荷分配任务,提出一种以可编程逻辑控制器PLC(Programmable Logic Controller)为核心的负荷分配控制系统.分析了负荷分配控制原理,完成了控制系统构成及实现方式的设计,编制了工作点与喘振区距离的算法逻辑...