主控制室核级空气喷射器性能影响因素研究

空气喷射器在非能动压水堆核电站发生事故时用于主控制室的应急通风。建立试验系统对空气喷射器的性能进行了研究,基于试验系统建立了模型,分析了空气喷射器的性能。认为压缩空气入口流量是影响空气喷射器喷射系数和出口空气压力的重要参数;喷嘴与混合腔的距离、喷嘴直径及混合腔截面与喷嘴出口面积之比是影响喷射系数和出口空气压力的重要因素。     

煤气引射器的实验及数值模拟研究

对煤气引射器进行实验研究,同时采用CFD软件对其进行了数值模拟.结果显示喉嘴距与面积比是影响引射器性能的两个主要参数.在流动参数一定时,引射器的喉嘴距与面积比都有一个最佳值.将实验和数值模拟结果进行对比,两者符合得很好,说明采用CFD方法进行低压引射器设计及分析是可行的.     

蒸氨引射器的合理应用

蒸氨引射器的合理应用李全来（唐山市焦化厂，０６３０２０）蒸氨引射器是利用蒸汽压缩器的原理，采用压力较高的蒸汽作为工质，经过高速喷射，抽吸蒸氨塔底弃液，两股蒸汽的动量交换和动量与冲量的转换等过程后，变成某一中等压力的混合蒸汽，进入蒸氨塔蒸氨。塔底弃液被...     

圆筒形混合室蒸汽喷射器的计算理论与实践

在蒸汽喷射热水采暖系统中,采用圆筒形混合室的蒸汽喷射器,与圆锥形混合室的相比,有以下几个特点: (1)可以实现小流量、较大温差、较高扬程,也可以实现大流量、小温差。单级蒸汽喷射热水采暖,供回水温差目前已能达到30～40℃,喷射器扬程10～25米水柱,供水温度在110℃左右(喷嘴前蒸汽压力P_P为2.5～5.0表压,引水室内水的静压P_H为1～2表压,相对压力Π=P_H/P_P≤0.5) (2)喷射器运行噪声小。在工作参数选用合适时,噪声可以控制在80分贝以内。 (3)可调节的范围较大。允许蒸汽压力有较大波动,或引水室内水的静压力有较大波动。     

运行参数对喷射器性能影响的实验研究

搭建了实验台,以CO_2气体为工质,对3种不同尺寸的喷射器进行了实验研究,分析了工作流体、引射流体的压力和温度对喷射器性能的影响。结果表明:当工作流体压力为8～10MPa时,随着工作流体压力的增大,喷射器喷射系数先逐渐增大后趋于平缓,压力为9.6MPa时,喷射系数达到最大值;当引射流体压力为2.4～2.9 MPa时,随着引射流体压力的增大,喷射系数先逐渐增大后趋于平缓,压力为2.8MPa时,喷射系数达到最大值;喷射系数随着工作流体和引射流体温度的升高而增大。     

蒸汽喷射两级加热器的研究

作者将蒸汽喷射器与汽水混合加热器两者相结合，构成蒸汽喷射两级加热器，用于工程，效果良好，本文介绍了蒸汽喷射两级加热器的构造、工作原理、试验情况和试验结果分析，指出了它的应用范围和经济性。     

蒸汽喷射器的设计及试验

本文介绍了常用的两种蒸汽喷射器的设计计算,阐述了求最大喷射系数及采用冲击波法确定混合室喉部断面的计算,重点介绍了对单体喷射器的试验,获得了不同型式的喷射器及喷嘴(相对尺寸不同,喷嘴出口到混合室入口距离不同,喉部长度不同以及喷射器的加工精度和喷射器的背压不尽相同)对喷射器性能影响的试验结果。     

蒸汽喷射真空泵混合室结构衍化的分析

从结构设计、工艺、成本等方面对蒸汽喷射真空泵混合室及喷嘴结构的衍化进行了分析。     

蒸汽喷射器节能原理及其在热电机组中的应用

本文从热力学角度阐明蒸汽喷射压缩器节能特性,并对衡量蒸汽喷射器节能性能的喷射系数作了理论推导,然后从引射减压、合理用能、回收工质促使废热资源化、简化系统结构、节约厂用电方面给出节能改造实例。由于节能环保,符合国家减排政策,因而具有推广利用价值。     

制冷用喷射器变工况性能的数值分析

用数值分析的方法对一制冷喷射器在非设计工况下的操作性能进行研究,计算并分析了工作流体压力、引射流体压力及背压等热力参数对喷射器性能的影响,并探讨了激波产生的条件及产生的位置。数值结果表明：提高工作流体的压力并不一定能改善喷射器的工作性能,这是因为提高工作流体压力不仅增加了额外的工作流体的质量流量,还会降低引射流体进入吸收室的推动力;当引射流体压力提高时喷射系数也随着提高;当背压低于某一临界压力值时,喷射系数保持不变,而工作流体和引射流体的混合流体必须经过斜激波来消耗一定的能量,以适应出口背压,增加了机械能的损失。     

Entrainment and its implications on microclimate ventilation systems: Scaling the velocity and temperature field of a round free jet

Research on microclimate ventilation systems, which mostly involve free jets, points to delivery of better ventilation in breathing zones. While the literature is comprehensive, the influence of contaminant entrainment in jet flows and its implications on the delivery of supplied air is not fully addressed. This paper presents and discusses entrainment characteristics of a jet issued from a round nozzle (0.05 m diameter), in relation to ventilation, by exploring the velocity and temperature fields of the jet flow. The results show a trend suggesting that increasing the Reynold number (Re) reduces ambient entrainment. As shown herein, about 30% concentration of ambient air entrained into the bulk jet flow at Re 2541 while Re 9233 had about 13% and 19% for Re = 6537/12 026 at downstream distance of 8 diameters (40 cm). The study discusses that “moderate to high” Re may be ideal to reduce contaminant entrainment, but this is limited by delivery distance and possibly the risk of occupant discomfort. Incorporating the entrainment mixing factor (the ratio of room contaminants entrained into a jet flow) in performance measurements is proposed, and further studies are recommended to verify results herein and test whether this is general to other nozzle configurations.     

正交试验法在微小型喷射器实验研究中的应用

在研究应用于小型太阳能喷射制冷系统的微小型喷射器实验中,根据已有理论和实际知识,决定选取结构参数,即等截面混合段长度、混合段进口到喷嘴出口距离,及引射流体压力作为试验因子,利用正交试验方法设计实验提高实验效率,以较少试验次数获得足够全面的实验结果。文中还探讨了评价试验对象性能的合理指标。     

液化石油气混空气中压引射器实验研究

本文在对中压引射器实验研究的基础上论述了引射器结构尺寸的确定问题。对实验结果进行分析，指出喷嘴轴向位置，混合管长度对引射器特性的影响。引射器实验特性曲线与计算特性曲线基本一致。引射器特性曲线具有体积混合比常数段。论述了混气系统工况调节方法。     

Flow field and acoustic characteristics of elliptical throat CD nozzle

The mixing characteristic of circular jet with elliptical throat is studied at different levels of expansion of the nozzle. Two kinds of configurations are studied in this paper, elliptical throat and circular throat jet. At all pressure ratios, the jet with non-circular throat experiences superior mixing than circular throat. The core length of elliptical throat jet is shorter than circular jet. Also, at all pressure ratios, the profile of both configurations looks identical in oscillation; however, the efficiency of the mixing promotion is high in non-circular throat. The promotion of mixing is most efficient at nozzle pressure ratio (NPR) level of 8. As the NPR increases, the core length of the jet reduces nearly 5–10% at each range of NPR. The centreline Pitot pressure profile of non-circular and circular throat shows that the decay of the jet from elliptical throat nozzle is faster than the jet from circular jet. At different levels of expansion, the shock structure shows notable changes with elliptical shape. The amplitude of screech frequency of the jet noise decreases with an increase in NPR. Introduction of elliptical throat to circular throat modifies the shock-cell structures, which significantly change the screech amplitude due to weakening of waves.     

带喷射器的CO2热泵热水器的循环特性研究

设计了适用于CO2热泵热水器的喷射器。分析了喷射器内部CO2流体压力、速度的变化趋势。建立了基于等压混合理论的喷射器模型,并对带喷射器的CO2热泵热水器系统进行热力学计算和火用损失分析。对带喷射器的热泵系统和带热力膨胀阀的传统热泵系统进行性能比较。考查了喷射系数、气体冷却器出口温度、蒸发温度等参数对系统制热系数的影响。     

Energy decay characteristics of a non-circular supersonic jet

In this paper, we study the energy decay characteristics of the nozzle at supersonic velocity. We have taken three types of configuration: circular, square and elliptical. The results are compared to the circular exit design. The experimental data are compared in relation to the pressure ratio. The throat area assumed to be constant. The supersonic potential core length of the different orientations is calculated. From the results, we have found that the exit geometry plays an important role in mixing promotion. The core length of a non-circular jet is less intense than a circular jet. The core length of the nozzle is the same in both under and overexpanded case. In addition to that, there is no sign of axis switching due to weak shock. The results are obtained in two different categories, total pressure data and numerical simulation. An empirical relation is used to investigate the core length experimentally.     

Mixing characteristics of elliptical throat sonic jets from orifice and nozzle

Aerodynamic mixing characteristics of the elliptical throat of the convergent divergent nozzle with an identical circular exit of aspect ratio 3 were studied computationally and experimentally. To determine the aerodynamic characteristics during mixing, the pressure distribution and pressure profiles were calibrated along the major and minor axes. The pressure variation in the orifice and nozzle shows that the energy decay in the nozzle dissipates faster than the jet from the orifice. Moreover, we visualised the pressure oscillation of the nozzle and orifices is closer to each other. In addition to that, we have also seen that the energy decay of both jets is approximately close to one another. The mixing promoting capability decreases as the area of the elliptical throat and the pressure gradient of the nozzle decrease. The computational results are evaluated with experimental values. The jet bifurcation is captured using StarCCM+.     

Steam jet ejector system for vehicle air conditioning

This paper describes the design of a steam jet ejector. The ejector forms the major component in an ejector cycle, which could be installed in vehicles to provide air-conditioning. The cycle could be driven by waste heat provided by the exhaust from the engine and/or cooling water supply.

The design of the ejector was derived from 1-D analysis, as well as from guidelines published in the ESDU series. The ejector was then manufactured and tested in a laboratory controlled test rig that simulated conditions present in a small motor vehicle.

The ejector analysis was then compared with the practical test data under design conditions as well as off design conditions. Comparisons were made using the mass flow ratio of the ejector. The coefficient of performance (COP_R) of the system is also presented for all operating conditions tested.     

上进风燃气灶引射性能的实验测试及数值模拟

文章对一种纯上进风燃气灶的引射性能进行了实验研究,通过气相色谱分析的方法确定了一次空气系数随着喷嘴前压力的变化规律。实验结果表明：随着喷嘴前压力的变化,上进风燃气灶的一次空气系数由于炉头温度较高而变化较火;同时利用CFD软件对上进风燃气灶进行三维稳态流动的数值模拟,并与实验得到的气相色谱分析数据对比,来验证由数值模拟计算上进风燃气灶引射能力的可行性,另外,对模拟出来的结果的速度场、温度场的分布进行模拟分析,实验及数值模拟的结果可供新型结构燃气灶的设计参考。     

太阳能喷射制冷系统微小型喷射器试验研究

蒸汽喷射式制冷系统可以采用太阳能、地热、废热等为驱动热源,以水等低沸点的环境友好工质为介质,不仅可节约大量的电能,而且还保护了环境。针对太阳能喷射式制冷系统中微小型喷射器的设计和运行问题,本文试验研究了微小型喷射器的运行参数和结构参数对喷射性能的影响,为微小型喷射器设计和运行提供了指导。