Design and Key Technology of Oil-Free Centrifugal Air Compressor for Hydrogen Fuel Cell

For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.

DISPLACEMENT CONTROL AND KINETIC ANALYSIS OF A NOVEL VARIABLE DISPLACEMENT COMPRESSOR FOR AUTOMOTIVE AIR CONDITIONER

A novel variable displacement compressor (VDC) for automotive air conditioner (AAC) is introduced, which inherits the advantages of common wobble plate type VDC. It has fewer parts and makes less noise, and instead of pneumatic valve the displacement is controlled by electronic control valve. In order to know the control mechanism well and get a good control effect, a mathematical model for the variable displacement mechanism is developed according to the geometrical and kinematical information of the compressor. Using the model, the effect of relevant parameters on variable displace control is estimated. It is helpful to make the optimum decision in the flow control of AAC. As the novel displacement control device, the structure and control rule of electronic control valve is introduced. It can get better effect than the conventional pneumatic valves. And by using this new electronic control device, the optimum systemic control of AAC is available.

Design of Piston Air Compressor Unit Control System based Converter

Based on the running characteristics and high energy consumption of air compressors in coal mines,an air pressure PID closed loop control system has been designed in this paper.The system is composed of PLC, converter and sensors etc and adopts the control method of converter triple-evaporator which makes air supply"need-based".The designed system has been applied in multiple coal mines and the results show its energy saving is remarkable and potential application is widely.

Girth welding system for vortex type refrigeration compressor of air conditioner

According to the requirements of welding process for vortex type compressor of air conditioner manufactured in product line, a special girth welding machine with PLC as control core was developed, which had both upright and 45 ° incline service positions. And some key technologies were researched, such as structural design of machine body, reliable conduction of rotary weldments and quality control of welding process and so on. The experimental results showed that this machine could satisfy the requirements of welding quality and girth welding technology, results also proved the machine was a high-effwiency and low-cost automatic welding device.

Steady air injection flow control for increasing the surge margin of radial flow compressor

Steady air injection upstream of the leading edge was used to increase the surge margin of a centrifugal compressor.To reveal the mechanism,steady numerical simulations were performed on a high pressure ratio centrifugal compressor rotor operated with a rotor tip speed of 586 m/s.Eight different injection yaw angle with four different injection mass flow was performed to determine the configuration that provide the best results for the compression system studied in this work.The injection angle,α,was fifteen degree and the injectors were placed at short distance（ten percent of the inlet tip radius upstream of the compressor face） to achieve maximum control over the leading edge flow by varying individual injection parameters.The results show that at design speed（n=50 000 r/min） with injection flow rate more than 2% of the main flow rate and yaw angle between 20° and 30°,the mass flow rate at stall decreases for approximately 8%.But with higher injection rate,other compressor parameters were affected such as compressor efficiency and compressor total pressure ratio.

Air Compressor Control System for Energy Saving in Locomotive Service Plant

The actuality and disadvantages of traditional high power asynchronism motor drive air compressor in locomotive ser-vice plant are discussed. In order to reduce the energy consumption and obtain safe running, a variable frequency con-trol method to the motor is supplied. A PLC with touch screen is used for monitoring the status of the compressor and its control system. It also presents energy consumption analysis caused by the variable frequency control method in a locomotive service plant.

Performance Analysis of Low Head Hydraulic Air Compressor

Hydraulic Air Compressor (HAC) is a device which converts hydraulic energy to energy of compressed air. A better exploitation of this hydraulic resource is currently investigated. The aim of the current work is to analyze a low head open type HAC in terms of compression ratio and HAC efficiency. The performance of HAC is both experimentally and theoretically investigated for various air admission system parameters (air tube length and diameter), downcomer length and hydraulic head. The results are both presented and discussed. Variation of the mean diameter of air bubbles in the downward flow in the downcomer is both determined and investigated. The losses in the whole system are classified, investigated and its impact on HAC is discussed.

涡轮压缩膨胀机的设计与性能分析

随着人们环境保护意识的加强,天然工质制冷剂重新受到研究人员的关注。空气是一种安全且对环境绝对友好的天然制冷剂,未来,压缩空气制冷循环有望成为传统蒸气压缩制冷循环的潜在替代品。压缩膨胀机作为压缩空气制冷的核心部件,其工作效率对机组性能有直接影响。为了设计出能够配合膨胀机高效工作的离心压缩机,需要对传统的设计方法进行一些修正。本文将质量、动量、能量守恒与射流尾迹区理论相结合,并将传统的离心压缩机相关参数推广到较低压力的范围中,提出了一种与现有的涡轮膨胀机相匹配的离心压缩机几何参数的设计方法。使用该方法为现有的膨胀机设计了对应的离心压缩机,并利用其他学者分析过的离心压缩机模型对该方法进行验证,利用计算流体力学方法(CFD)对压缩膨胀机变工况下的工作性能及对膨胀功的利用率进行模拟分析。按本方法设计的离心压缩机在设计工况下能够以高于92%的效率利用膨胀机的输出功。在变工况条件下能够以高于88%的效率利用膨胀机的输出功,并且在设计质量流量附近能够顺利运行。

燃料电池空压机气磁悬浮系统的协同控制研究

针对燃料电池空压机目前存在的驱动和支承问题,提出一种箔片动压轴承和动力磁轴承一体化的气磁悬浮型空压机。基于空压机的结构组成,建立空压机磁悬浮支承力、气悬浮支承力以及空压机转子动力学数学模型;基于燃料电池空压机转子系统动力学模型的状态空间方程,设计抗干扰强的协同控制器,并对它进行了转速、驱动转矩、转子悬浮位移以及电磁调节力等关键物理量的仿真分析。结果表明:协同控制在响应、抗干扰以及鲁棒性方面的控制优于PID控制。基于协同控制和PID控制建立了控制实验平台,并对空压机转子的气磁悬浮进行分析,进一步验证了协同控制具有优良的控制效果和良好的控制性能。

基于数字孪生技术的往复式空气压缩机效率预测方法研究

通过建立往复式空气压缩机数字孪生体模型,实现压缩机效率预测和参数寻优的方法,具有灵活、成本低、通用性好的优势.但是在多变量条件下,传统的基于BP神经网络孪生模型训练时间长、工作量大,寻优过程易陷入局部最优解,不易实现全局最优.针对传统孪生体模型存在的问题,提出了基于CIWOA-BPNN算法的孪生体模型构建方法,通过主成分分析法确定孪生体模型关键指标,在BPNN模型基础之上引入改进的鲸鱼优化算法.研究表明,基于CIWOA-BPNN算法的孪生体模型有效避免了BPNN模型陷入局部最优解.用CIWOA-BPNN算法预测压缩机效率相对误差小于0.6%,决定系数为0.99775,与传统模型相比大幅提升了预测精度.

基于DBN和BES-LSSVM的矿用压风机异常状态识别方法

针对矿用压风机这类分布式系统的异常类别复杂、识别精度低等问题,提出了一种基于深度置信网络(DBN)和最小二乘支持向量机(LSSVM)的异常状态识别方法。首先,分析压风机组成系统及其运行机理,确定常见的异常状态类型;其次,采用DBN无监督学习方式充分挖掘监测数据中异常特征并快速提取;然后,利用秃鹰搜索算法(BES)优化LSSVM的超参数,构建最优的BES-LSSVM分类模型;最后,将DBN提取的异常特征作为BES-LSSVM模型的输入,对矿用压风机异常状态进行识别。试验验证与对比分析结果表明,相较于GA,PSO,GWO算法,BES算法的求解精度和收敛速度均有所提高,同时DBN-BES-LSSVM模型在测试集上平均识别精度达到94.65%,较PCA-LSSVM模型、DBN模型和DBN-LSSVM模型的识别精度分别提高了10.53%,5.84%和3.76%,验证了DBN-BES-LSSVM模型在矿用压风机异常特征提取以及特征识别方面的优越性。

基于线激光的压缩机曲轴圆度和平面度测量

目前人工使用千分表测量空调压缩机曲轴圆度和平面度时存在易伤工件表面、效率低和不能精确评定等问题。针对上述问题,设计了一套基于线激光位移传感器的空调压缩机曲轴圆度和平面度非接触式测量系统。首先,通过测量标准量棒,提出一种系统误差的标定方法;其次,基于线激光采样数据,开发了一种曲轴横截面圆度测点的提取算法,并将系统误差用于测点补偿,实现曲轴圆度测量;接着根据曲轴平面测点间的斜率分离出轮廓线,通过均匀下采样方法获取精简点云数据并采用最小二乘法实现曲轴平面度测量;最后,基于上述方法开展了曲轴圆度和平面度的测量实验。实验结果表明:该测量系统的圆度测量精度<4μm,平面度测量精度<2μm,圆度重复度测量误差<0.8μm,平面度重复度测量误差<0.3μm,满足曲轴圆度和平面度快速准确的测量需求。

4DI110型空压机的技术改造与操作优化

文章通过介绍新引进的4DI110型离心式空压机(以下简称“空压机”)试运行阶段开始以来的运行情况和气温变化对空压机出口流量造成的影响,分析空压机出口流量随气温变化而变化的规律,指出空压机防喘阀V3004阀不能自动调节出口压力,影响空分装置工况的稳定。为实现空压机出口压力的稳定,对其防喘阀V3004阀采取增设自动旁路阀V3008阀的技术改造,同时优化和完善相关逻辑控制并阐述了空压机经技术改造后的操作优化和取得的实际效果。

污水曝氧工艺技术研究

大庆油田聚驱用聚合物常使用含聚污水进行调配,但含聚污水中存在大量S^(2-)、Fe^(2+)等离子,会对聚合物分子产生严重的降解作用,造成稀释母液时降低溶液黏度,影响驱油效果。为有效清除溶液中还原性离子含量,可采用曝氧工艺对含聚污水进行处理。通过实验,将曝氧气头换为盘式曝氧器,重新设计工艺流程,可提高曝氧效率,节约能耗。盘式曝氧工艺在气水比5∶1,曝氧时间3~6 h条件下,污水溶氧量达到5 mg/L以上,配制黏度提高7.6%以上,能有效降低含聚采出水中的还原性物质含量,聚合物溶液稳定性大幅提升,保证聚驱稀释用水溶氧值满足开发效果。

基于Simulink的双压缩机空调分段除霜模拟

针对寒冷及严寒地区空调制热运行下除霜展开研究,设计一种双压缩机热气旁通式分段除霜空调并进行仿真模拟。结果表明,该模型在寒冷地区的气候条件下正常运行,保证室内温度趋于稳定,并能够分段进行有效除霜。变制冷剂流量多联式空调系统(新型VRV空调系统)适用于寒冷地区冬季的供暖,为新型VRV空调供暖在寒冷地区的应用提供参考。

汽车空调涡旋压缩机排气孔优化研究

针对汽车空调涡旋压缩机排气孔处气体流动变化产生的流动损失问题,对排气孔结构进行优化,以期降低流动损失并提高排气压力。通过三维动网格模型对不同排气孔结构的涡旋压缩机排气过程进行瞬态仿真,发现腰果形排气孔更大的截面积使其拥有更好的开启特性,可有效降低排气损失,提高排气稳定性。在对腰果形排气孔采取进一步扩压式优化后,发现其可以更加有效地降低排气速度并提高排气压力。

压气机叶顶间隙流动与控制研究进展

压缩空气储能被视为最具发展潜力的物理储能技术,作为其核心部件,压气机的性能表现在较大程度上决定着储能系统的经济性和效率。叶顶间隙流动因其复杂的三维流动特性,对压气机内部流场结构变化存在重要作用,是影响整机性能的关键因素。文章依照叶顶结构特点分类总结了带冠、无冠轴流压气机和开式/半开式、闭式离心压气机叶顶间隙流动产生的机理,根据压气机流动特性,进一步综述国内外压气机叶顶间隙流动的研究进展,形成以下结论:对于无冠轴流压气机,非定常叶顶间隙流动与失速、叶片噪声及振动问题密切相关,需扩充研究成果以优化叶顶设计;带冠轴流压气机缺乏实验和数据支撑,流动控制手段单一,可尝试跨领域应用控制技术;离心压气机叶顶间隙流动研究仍需探索变间隙特性和周向不均匀性对流动结构的影响,并提升应对流场变化的能力。未来研究可着重于高精度数值模拟方法的应用推广、跨领域控制技术的尝试和复合结构的探索。

1,2-环己烷二甲酸双酯在空气压缩机油中的应用

对比考察了邻苯二甲酸二异辛酯和1,2-环己烷二甲酸二异辛酯,邻苯二甲酸二异癸酯和1,2-环己烷二甲酸二异癸酯的理化性能及其相应成品油的综合性能,环己烷二元酸酯及其成品油40℃黏度相对略低,但是黏度指数相对较高;其高低温性能略差,但是其成品油的高温性能、黏度指数以及低温性能均表现良好。

高效双级喷油螺杆空压机的研究与开发

为了实现空压机设备的能效提升,开发了1台额定功率为250 kW的双级喷油螺杆空压机,空压机的低、高压级均采用新型螺杆转子型线,压缩机在结构上采用了一系列创新设计,对级间压力、喷油量等关键运行参数进行了优化,并通过试验测试对所开发双级喷油螺杆空压机样机的能效进行了评估。结果表明,在最佳转速为1330 r/min时,容积效率可达到95.6%,低压级和高压级压缩机的绝热效率则分别达到93.3%,88.6%;依据GB 19153—2019对样机能效进行评估,在100%,70%和40%负载下,样机均可达到定转速喷油回转空压机一级能效,考虑到空压机在额定负载与部分负载时的综合性能,其机组比功率可达到5.72 kW/(m^(3)·min),相较于一级能效限定值低了7.7%,达到了“双一级能效”,实现了同类螺杆空压机产品的能效升级。此外,通过试验研究了转速变化对双级喷油螺杆空压机低、高压级p-V指示曲线和效率的影响规律。经研究发现,低压级压缩过程p-V曲线低于等熵压缩过程,转速变化对其影响较小,而高压级压缩过程p-V曲线受气体泄漏影响显著,转速升高会导致高压级压缩过程曲线逐渐变缓;低压级和高压级压缩机效率随转速变化呈现出不同的变化规律,且高压级压缩机的容积效率和绝热效率均对转速变化非常敏感。研究结果可为螺杆空压机的能效升级提供参考价值。