永磁同步直线电动机冷却系统结构设计

永磁同步直线电动机运行过程中产生大量的热量,严重影响电动机的正常运行。现提出一种结构简单、性能可靠的电动机水冷冷却系统。在设计中采用Ansys有限元分析软件对永磁同步直线电动机进行了三维温度场计算,清晰展示出电动机内部各部分的温度以及整个电动机的温度曲线。针对该温度场,设计相应的水冷冷却结构,并再次模拟仿真出带冷却系统的电动机温度场分布。最后通过温升实验,验证了计算结果,并证明上述水冷冷却结构的工程可行性,解决了长期困扰中国大功率直线电动机发热严重的问题。     

硅整流柜纯水冷却系统的改造

通过对包头铝厂二期铝电解直流供电系统中硅整流柜纯水冷却循环装置更新改造的阐述,说明硅整流柜的分列水冷方式是目前取代集中水冷方式的一种理想的冷却方式,在大型电解硅整流供电的集中式水冷系统设备更新改造中极有推广使用价值.     

大功率压接式功率器件用水冷基板研究

针对大功率压接式功率器件的散热需求,进行用于其冷却的水冷基板设计与研究.根据压接式功率器件用水冷基板结构特点和技术要求,设计内部冷却流道为螺旋线结构,使用UG软件建立三维模型,应用仿真软件计算得出其温度场分布云图和压力分布云图,并对产品进行热性能试验和压接试验.结果显示,表面研制的水冷基板仿真计算结果与试验结果相近,热阻和流阻参数指标满足技术条件要求,功率模块区域均温性良好,且产品可靠性满足设计及实际运用要求.该研究内容为类似结构水冷基板设计提供参考.     

大功率压接式功率器件用水冷基板研究

针对大功率压接式功率器件的散热需求,进行用于其冷却的水冷基板设计与研究.根据压接式功率器件用水冷基板结构特点和技术要求,设计内部冷却流道为螺旋线结构,使用UG软件建立三维模型,应用仿真软件计算得出其温度场分布云图和压力分布云图,并对产品进行热性能试验和压接试验.结果显示,表面研制的水冷基板仿真计算结果与试验结果相近,热阻和流阻参数指标满足技术条件要求,功率模块区域均温性良好,且产品可靠性满足设计及实际运用要求.该研究内容为类似结构水冷基板设计提供参考.     

某高热流密度冷板的设计与优化

某吸收电阻模块发热功率大且热流密度高,冷却系统的设计既是重点也是难点,冷却系统的好坏直接关系到模块能否正常工作。文中探讨了某高热流密度与大发热功率并存的散热问题,选择强迫液冷作为其冷却方式。通过仿真分析对冷板结构进行不断的优化,通过增加散热齿并改变散热齿结构,使冷板满足器件散热需求。运用ANSYS模拟了冷板盖板不同结构形式的密封性能,通过采用有筋的不锈钢盖板,可取得良好的密封性能,缩短冷板加工周期并降低成本。装机后对该冷板的实物测试证明了该冷板的可行性。     

某电子设备整机结构热设计

文中以某电子设备研发为例,根据产品实际工况,利用工程经验公式对该设备的热设计进行了分析计算,确定了设备的冷却方式、风机规格及散热器参数等。在此基础上,采用Icepak热分析软件对设备的温度场分布情况进行了仿真。随后,根据环境适应性指标开展了温度试验,并与仿真结果进行了对比。仿真和试验的结果表明：该设备的热设计满足系统的环境适应性指标要求,理论计算和热仿真分析方法实用、有效,对同类设备的设计具有重要的参考价值。     

水冷散热器温度场及热变形的模拟分析

水冷散热器是保证大功率电气设备正常工作的有效散热装置,其热交换过程及热膨胀变形一直是研究的热点。针对某企业一款水冷散热器的核心部分-水冷部件,应用有限元软件ANSYS建立起其单路冷却流道的模拟模型,分析流体入口流速、空气热对流对流体出口温度的影响以及水冷部件产生的热变形。研究结果表明,流体出口温度随着其流体入口流速、空气热对流系数分别呈现曲线下降、近似线性下降的趋势;水冷部件的热膨胀变形十分明显、且分布不均匀,出现了翘曲现象。     

摩托车水冷系统的设计分析

本研究综合分析国内外在摩托车水冷系统方面的研究,并基于此对摩托车水冷发动机开展先相关课题研究,进一步探究了250cc水冷发动机的冷却泵叶轮性能。大多数学者通常借助试验法来分析摩托车发动机冷却泵,存在投入大、设计周期较长以及质量不高等问题,本研究就提出了对于摩托车水冷发动机冷却泵通过仿真分析法进行研究,同时利用实验研究的方式来验证优化设计方案,提高水冷系统的设计效率。     

水冷电机冷却系统设计与计算

针对水泵驱动的异步电机进行水冷冷却系统的设计和计算,提出一种电机水冷冷却系统的计算模型.在设计中采用水循环外冷却方式取代普通电动机的散热风扇,对电机机座进行冷却;利用流体力学和传热学理论及方法,对该冷却系统进行管路计算;最后通过水冷与风冷系统的定量比较,阐述了水冷系统的优点与局限性.此冷却系统可应用于一般清水离心泵,具有结构简单、高效节能和噪音低等优点.     

电机类装置冷却方式综述

电机类装置的冷却问题就是把其运行时产生的电磁损耗所形成的热量散发出去.线圈炮的散热问题,一直是阻碍其发展的技术难关.通过对电机各种冷却方式的原理及优缺点等的阐述,希望从中找出解决线圈炮散热问题的途径.蒸发冷却技术是冷却方面的新技术,其具有冷却效果好,运行温度低,线圈压力小,安全性能好等特点,比较符合电磁炮冷却系统的要求.     

一种电源变换器散热的研究

讨论了机载电子设备中经常使用的一种电源变换器在三种散热方式（辐射,传导,对流）下的散热问题,同时给出了一些计算公式。     

Thermoelastic stability of duplex heat exchanger tubes

When duplex tubes are used for heat exchange purposes, thermal distortion affects the contact pressure and, hence, the thermal contact resistance at the interface. The resulting coupling between the thermal and thermoelastic fields for the system can lead to instability and non-uniqueness of the steady-state solution and, hence, to erratic heat transfer performance.Stability of the system is investigated by determining the conditions under which a small (axisymmetric or non-axisymmetric) perturbation on the steady state can grow exponentially in time. Substitution into the governing heat conduction and thermoelastic equations enables the unknown functions to be determined except for a set of arbitrary constants, which are then determined from the thermal and mechanical boundary conditions, including a statement of the relation between thermal contact resistance and pressure, linearized for small perturbations about the steady state.Results are presented for a range of material combinations and for both directions of steady state heat flux. It is shown that unstable axisymmetric perturbations can only occur for inward heat flow and, hence, the stability boundary for outward heat flow is always associated with a non-axisymmetric mode. In the latter case, the circumferential wavelength of the critical mode is generally about twice the tube thickness and a good approximation to the stability boundary can be obtained using previously published results for the stability of two plane layers in thermoelastic contact.For inward heat flow, the critical heat flux for axisymmetric perturbations is independent of the mean contact resistance, whereas that for non-axisymmetric modes increases with contact resistance. Thus, the stability boundary in this case is determined by non-axisymmetric modes for small values of contact resistance and by axisymmetric modes for large contact resistance.     

Numerical simulation of operation heat modes of multidisc oil-cooled vehicle brake. Part 1. Heat problem solution

The paper considers the operating heat modes of multidisc oil-cooled vehicle brakes under single and multiple braking, as well as under deceleration over a long downgrade. The initially boundary-value heat problem for the given operating modes of the brake is formulated and solved by the finite-element method. The regularities of formation of nonstationary temperature fields both on the contact surfaces and in the bulk of the brake friction elements are obtained for preset braking modes. The dependences are obtained for the maximal contact surface temperature on the metal counterbody and frictional material vs. the load and velocity parameters of vehicle motion. A method for forecasting the critical operating regimes of multidisc oil-cooled brakes is proposed for the given operation conditions of the vehicle.     

Film-wise and drop-wise condensation of steam on short inclined plates

Film-wise and drop-wise condensation experiments were carried out at atmospheric pressure varying the condensing plates, their inclinations and orientations (upward or downward facing), and the air concentrations. As expected, dropwise condensation showed much higher heat transfer rates than corresponding film-wise condensation in the pure steam cases. However, with the presence of air, both modes of condensation showed similar heat transfer rates due to the high thermal resistance of the air-rich layer. Both modes of condensation showed systematic decreases in heat transfer as the angle of the plate to the horizontal decreased and as the concentration of air increased. A noteworthy observation made during the tests on the plate orientation showed that condensation heat transfer rates on the upward facing plate were slightly higher than those beneath the downward facing plate in the pure steam cases but that the trends were reversed in the steam and air mixture cases.     

Thermal displacement error compensation in temperature domain

Thermal displacement errors are becoming more and more important in the precision engineering field where the specifications are ever increasing. This paper proposes a novel technique to compensate in-plane thermal displacement errors in a thin plate under a moving disturbance heat load. The displacement error is evaluated at the point of the moving heat load. The technique utilizes Thermal Modal Analysis (TMA) as a means to analyze the transient temperature distribution in the plate and estimate the thermal displacement field resulting from that temperature field. The temperature field is controlled by applying additional heat loads to the plate to control and eliminate some of the modes in the temperature domain which have the largest influence to the thermal displacement error. The theory of thermal modal analysis and the developed technique of controlling modes in the temperature domain are explained. The experimental setup and results are shown to validate the control of the thermal modes.     

肋片焊接方式对其传热的影响

通过改变肋片的焊接尺寸以及焊接形状建立肋片传热模型,采用CFD(Computational Fluid Dynamic)模拟的方法,将模拟结果与传统铸造肋片的传热情况进行对比,研究不同焊接方式以及焊接尺寸对整个肋片的换热量以及换热系数的影响.结果显示,肋片焊接后,对整个肋片的换热量和换热系数有一定的影响,但影响较小.其中换热量根据焊接尺寸的增加先减小后增大;而换热系数呈波浪形变化,但有减小的趋势.     

A study of the Newkirk effect in turbomachinery

An analytical and experimental study was undertaken on the Newkirk Effect as applied to turbomachinery which is the vibration change produced when a high speed rotor rubs on stationary components due to the uneven distribution of the produced heat around the rotor. The analysis predicted three possible modes of the Newkirk Effect: spiralling, oscillatory and constant modes. The first is associated with very high vibration amplitudes and the latter two with low amplitudes, even vibration suppression and may be considered as stable modes.To support and verify analysis, an experimental rig was constructed and a limited number of tests conducted. The test results verified both quantitatively and qualitatively the analytical findings for the modes of the Newkirk Effect. The parameter study indicated that stability of the system does not depend explicitly on whether the running speed is below or above the critical speed, but rather on the phase angle between static and dynamic bow. This is a dynamic property of the system unrelated to the friction characteristics. It depends, to a lesser extent, upon the amount of generated heat and the other characteristics of the system. The clearance was found to be a very important factor. The existence of a threshold value of the clearance was demonstrated.     

Control over the Heat-Wave Amplitude-Frequency Characteristics during Crystal Growth in an Apparatus with Heat-Field Rotation

A computer-compatible device for controlling an apparatus, which is designed for growing crystals under contactless excitation of forced convection in a melt-solution by the heat-field rotation, is described. The device allows for a more flexible control over the amplitude–frequency characteristics of the heat field. Several control modes and the corresponding characteristics of the heat wave produced by the rotating heat field are presented.     

地源热泵U型管换热器夏季工况试验分析

U型管换热器设计是土壤源热泵系统应用的关键,埋管深度、管内流速、土壤初始温度、运行模式等都是影响其性能的主要因素,利用上海地区所建设的不同埋深U型换热器(60m,90m)土壤源热泵试验装置,进行了夏季工况试验,测得热泵运行前土壤初始温度分布;测试了热泵机组间歇和连续运行时换热器的换热情况;还针对不同埋管内冷却水流速,测得到了单位孔深换热量,结果表明增加冷却水流速并不能一味地提高其每延米换热量,埋管内冷却水流速存在一个最佳值。     

燃气机冷水机组热经济性分析

利用热力学第一定律,分析得出燃气机冷水机组在供暖时一次能源利用率高于其他供热方式,同时对比了燃气机冷水机组和电动冷水机组的运行费用,可以看出燃气机冷水机组的运行成本低于电动冷水机组。针对冷水机组的应用场合设计了热回收系统,为燃气机驱动冷水机组实用化提供了设计参考。