【作者】 孙妍；

【导师】 陈贵军；

【作者基本信息】 大连理工大学 ， 热能工程， 2011， 硕士

【摘要】 喷射泵是一种用来传递能量、质量的流体机械设备。在喷射泵中两股不同压力的流体相互混合,发生能量交换后形成一种居中压力的混合流体。喷射泵提高引射流体的压力而不直接消耗机械能,并且由于它自身具有的独特优点如工作可靠、没有转动部件、安装维护方便等受到人们的青睐而被广泛的应用到了工程实际的各个领域中。本文通过商用软件FLUENT对喷射泵的内部流场进行分析,并在此基础上分析了喷射泵结构参数和工作参数及其变化对喷射泵性能的影响。应用喷射泵的引射增压功能,设计了输送高温饱和水的离心式水泵的防汽蚀装置,同时对防汽蚀装置的工作性能进行了深入的研究。本文的主要工作如下：1.根据能量守恒原理和动量守恒原理推导出喷射泵的性能曲线及最佳截面比的公式,为防汽蚀装置中喷射泵的设计计算和性能分析奠定基础。2.针对喷射泵进行物理和几何建模,应用商用软件FLUENT分析喷射泵内部流动压力和速度的变化。并且分析了喉管入口收缩角对喷射泵性能的影响,经过计算本文发现喉部入口收缩角在20°至45°之间白选取对喷射泵的效率影响不大,并且发现喉部入口收缩角较小时喷射泵更容易发生汽蚀。3.在喷射泵数值计算的基础上分析截面比为6-11的喷射泵的工作压力、引射压力、出口混合压力对其性能的影响以及当喷射泵总扬程不变时吸上高度和排出压力与流量比之间的关系。4.在喷射泵内部流场、性能分析的基础上,建立基于喷射泵的防汽蚀装置性能计算模型。并对防汽蚀装置的变工况运行规律进行研究。更多还原

【Abstract】 Jet pump is a sort of fluid machinery using for mass and energy transfer, which has been widely used in many industrial fields due to its unique advantage, e.g. high reliability, no rotatable parts involved, easy installation and maintenance.In this study, the commercial available CFD software FLUENT is employed to analyze the flow field inside the jet pump and then clarify the pump structure and working parameters on the working performance. Moreover, the performance of the cavitation-prevent device is also investigated based on the obtained results. The detailed contents of this study are listed as following:1. The jet pump performance curve and optimum area ratio equation derived from the momentum and energy equation provide reference to the design and performance analysis of the jet pump of a cavitation-prevent device.2. The flow field inside the jet pump is modeled by the aid of FLUENT to study the pressure and velocity variation of the flow inside the jet pump. The effect of choke inlet falloff angle on the pump performance is also examined and it is found that the falloff angle ranging between 20°and 45°has no significant on the jet pump efficiency and small falloff angle contributes to the occurrence of cavitation.3. Based on the simulation results, the investigation on the effect of working pressure, ejector pressure and outlet pressure on the performance of an injector pump with the cross-section ratio of 6/11 is conducted. Moreover, the relationship between the outlet pressure, suction height and the flow rate is also studied at the condition of unchanged pump lift.4. A model for predicting the performance of the cavitation-prevent device is developed based on the internal flow field and performance analysis of the jet pump. Additionally, the working law of the cavitation-prevent device under variable working condition is also studied.更多还原