共查询到18条相似文献,搜索用时 78 毫秒
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膨胀阀性能对比的实验研究 总被引:2,自引:1,他引:1
对热力膨胀阀、步进电机型膨胀阀以及电磁阀型膨胀阀在制冷系统开机以及稳定运行的情况进行了实验研究,结果表明电子膨胀阀适合用于系统综合控制器中;连续调节型的执行机构比离散调节型的执行机构更容易使过热度稳定;积分环节大大改善了过热度的控制品质。 相似文献
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介绍了对H型、F型热力膨胀阀和电子膨胀阀所进行的动态响应特性实验,验证了膨胀阀感受过热度的响应近似于一阶惯性延迟环节,给出了响应的延迟和时间常数值以及流量系数关系式。 相似文献
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在制冷陈列柜制冷系统的基础上建立脉冲式膨胀阀制冷系统的性能试验台,通过调节脉冲电子信号,对脉冲膨胀阀进行了节流特性的试验研究.试验得出了脉冲膨胀阀的节流特性规律,指出对脉冲膨胀阀节流特性有影响的因素.研究表明供液系数是影响制冷系统蒸发温度的主要因素,而脉冲频率会影响系统达到稳定的时间以及蒸发温度的波动情况,并对三种节流机构(热力膨胀阀、电子膨胀阀和脉冲膨胀阀)进行了性能对比试验.研究表明使用脉冲膨胀阀的蒸发器蒸发温度变化规律有别于热力膨胀阀和传统的电子膨胀阀.蒸发器入口和出口的温度在开机很短时间内就能达到稳定的蒸发温度,并能稳定在很小的过热度范围内.使用脉冲膨胀阀的制冷系统能很好的实现制冷循环的节流效果,调节脉冲信号可使系统满足工况变化的要求. 相似文献
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目前空调市场上一对一热泵空调器以其冷热兼用、安装使用简便等特点受到市场的广泛青睐。电子膨胀阀可按电脑设定程序进行流量调节,它适应制冷系统机电一体化的要求,具有传统热力膨胀阀的优点并抛弃了其存在的缺陷。本文通过对电子膨胀阀作为节流机构等一系列作用描述,深刻探讨了一对一热泵空调器采用电子膨胀阀进行控制的优点。 相似文献
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Eunjun Cho Manyeong Ha Sedong Chang Yoonjei Hwang 《Journal of Mechanical Science and Technology》2011,25(1):201-208
The aim of this study is to determine the electronic expansion valve (EEV) opening using a fuzzy table when the superheating
of a variable capacity air conditioning system is controlled via fuzzy control. Optimum opening of EEV is determined by applying
superheat control method, where factors including superheat error and superheat gradient, as well as compressor capacity,
indoor temperature, outdoor temperature, and indoor fan rpm, are considered. This control algorithm uses a fuzzy table wherein
values are changed to optimal values according to operating conditions, enabling fast and stable control. 相似文献
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Chin-Tarn Kwan 《The International Journal of Advanced Manufacturing Technology》2005,26(9-10):983-990
In this paper, two process and die design methods for ball valve forming from stainless steel tubes are compared: one is the tube hydroforming method (THFM), and the other is the tube nosing method (TNSM). Simulations on hydraulic expansion, axial feeding, and tube nosing of the ball shell forming with the two methods using the program DEFORM-3D are carried out. The influence of the two methods on workpiece formability and wall thickness distribution of ball valve forming is examined. A tube nosing experiment is carried out with a SUS304 stainless steel tube at room temperature. An accepted product of ball valve satisfying the industrial demand is obtained using TNSM. 相似文献
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The increase in common rail pressure can lead to increased cavitation inside the injector, resulting in degradation of injector performance and reduced life. The paper investigates the effect of the pressure block structure parameters (initial flow area around the ball valve) on the velocity field, pressure field, fuel gas phase volume fraction and drain rate of the control valve. The relationship between the initial flow area around the ball valve on the cavitation strength and unloading rate inside the valve was revealed. The results show that both the reduction of the flow area around the ball valve and the increase of the cavitation intensity inhibit the rate of oil discharge from the control valve. The reduction of the fuel flow area inhibits the expansion of the low-pressure region (0–1 MPa) within the flow layer, thus limiting the development of cavitation. The reduction of the cavitation area increases the fuel flow rate, however, the increase in flow rate increases the cavitation phenomenon, and these changes form a cycle (Reviewer 5. comment 2). The increase in cavitation inhibits the control valve pressure relief rate more significantly than the decrease in the initial flow area around the ball valve. Based on this, a stepped-pressure block model is proposed. The stepped pressure block model can effectively reduce the cavitation strength near the seal and enhance the oil discharge rate of the control valve. The study can provide a reference for the engineering optimization design of high-pressure common rail injector control valves. 相似文献