采用变频压缩机的风冷冰箱系统性能研究

通过实验及模拟手段,对采用变频压缩机的风冷冰箱在压缩机不同转速时的耗电量、功率及开机率进行了研究。同时还研究了压缩机在不同转速条件下,冰箱的冷藏室、冷冻室、果蔬室及制冰室等主要间室内的温度变化情况。实验结果表明：当压缩机在最优运转速度时,冰箱的各个间室温度变化能控制在良好的范围内,其中冷藏室平均温度为4.1℃,最大温度波动为3.4℃、果蔬室平均温度6.1℃,最大温度波动为1.0℃。在各个测试间室温度满足国家标准要求的条件下,变频压缩机可以使该风冷冰箱的耗电量达到0.908kWh/d左右（不带负载）。另外冰箱系统的软件模拟结果与实验数据相比,当压缩机转速为3000r/min时,最大偏差为16.2%,而在压缩机转速为1900r/min时,模拟和测试结果吻合较好,其偏差降为8.6%。此实验结果验证了模拟软件的可靠性,同时也表明冰箱系统模型仍需进一步优化。     

换热管与管板的连接工艺试验

在现代空分设备上,离心压缩机使用的二级冷却器采用贴胀+密封焊连接的不锈钢内翅片换热管与管板会经常出现窜漏。为了解决二级冷却器换热管与管板连接的泄漏问题,重新做换热管与管板的连接工艺试验。通过试验得出结论:换热管与管板的连接应采用强度胀连接。     

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.     

Coexisting phenomena of surge and rotating stall in an axial flow compressor

The unsteady inner flow structure of a single-stage axial flow compressor under the coexisting conditions of surge and rotating stall was experimentally investigated via detailed measurements of the unsteady characteristics and the internal flow velocity fluctuations. The main relevant feature of the tested compressor is a shock tube with a capacity tank connected in series to the compressor outlet through slits and a concentric duplex pipe： surge and rotating stall can both be generated by connecting the shock tube. Research attention is focused on the unsteady behavior of a rotating stall during the surge cycle. The size of the rotating stall cell during the recovery process of an irregular surge cycle was experimentally determined by the circumferential flow velocity fluctuations ahead of the rotor blade. The results suggested that the size of the rotating stall cell at the switching point of the performance curve between large and small cycles is considered to be the key parameter in determining the following surge cycle. In addition, the surge cycle is largely influenced by the unsteady behavior of the rotating stall cell.     

一起空压机未遂事故原因解析与对策

分析解决了空气压缩机因直连拖动同步电动机投励时间滞后引起的启动失败故障,以及设备制造、安装质量造成的运行安全隐患,提出了空压机电气设计、安装与运行安全对策措施。     

4L-20／8空气压缩机智能化控制技术及应用实践

通过分析4L-20／8空气压缩机的运行工况,使用气量与压气量动态匹配,实现电动机转速无级调节,防止电动机在空载下运行,并将用产气量作为改进空气压缩机智能化控制的备件。智能化控制方法利用微机控制管理系统,用一套智能化控制系统驱动多台4L-20／8空气压缩机,进行一拖多控制,在储气罐的压力管道上安装压力传感器,实现对空气压缩机的控制与调节。通过对4L-20／8空气压缩机进行智能化控制,可以降低能源消耗,减少设备的维修保养工作量,从而实现空气压缩机无人值守自动运行,该系统改造的成功,为此类型空气压缩机的节能运行提供了新手段,对于企业节能降耗,提高企业经济效益有重要意义,有广阔的推广应用前景。     

75000m池空分空压机主油泵压力低原因分析与处理

针对主油泵油压低问题分析原因,不停机情况下逐一排除可能性,最终确定主油泵吸入过滤嘴堵塞是造成了主油泵压力的原因,清理后运行压力恢复。     

C125MX5N2型氮气透平压缩机冷却系统改造

介绍了C125MX5N2型氮压机冷却系统因循环水总管设计偏小,重新设计设计改造管路。通过改造本体,解决压缩机本体1～4级进口管路偏小截流问题,实现压缩机排气温度的降低。     

浅谈PAP PLUS系列离心式空压机漏油的治理

介绍贵冶动力车间PAP PLUS系列离心式空压机轴封方式,对空压机运行时齿轮箱底座、轴封出现漏油现象进行分析。阐述了通过引入射流装置使齿轮箱和油箱形成"负压"从而彻底治理渗漏点的一种办法,并对射流装置结构原理、基本理论及设计依据进行介绍。     

Aerodynamic experimental investigation using stereolithography fabricated test models: the case of a linear compressor blading cascade

The purpose of this work is to demonstrate that rapid prototyping can be effectively applied for fabricating test models to be used in aerodynamic experimental investigations. The present work, in particular, concerns a linear cascade of 2½-D blades, with NACA 65-12(A10)10 profile section. Each one of the nine separate (identical) blades of the cascade has been fabricated using a stereolithography rapid prototyping technique. The cascade has been installed in an aerodynamic test rig, in order to simulate the flow conditions through a compressor blading. Aspects concerning the fabrication of the test models/blades, their functionality, their post-processing, the mounting arrangement and the pressure tubing and ports are discussed in detail. Experimental results for the distribution of the blade surface airflow pressure for various incidence angles compare favourably with computational results obtained with a panel inviscid flow numerical scheme. This implicitly indicates the effectiveness of employing stereolithography for fabricating wind tunnel test models.