沟槽式微热管封口机构设计

研究了沟槽式微热管制造过程中的封口工艺.微热管封口压力曲线由专用压力机测定,然后通过分析压力位移曲线图来选择合适的封口压力,并根据压力大小设计一种简易的增力机构,联合Pro/E和ADAMS软件对机构进行建模仿真,结果表明,所设计的封口机构在较小的压力输入下能获得期望的钳口压力.     

不同工质沟槽式微热管传热性能实验研究

为了研究工质对沟槽式微热管传热性能的影响,通过试验对不同充液率下,不同工质对沟槽式微热管的温差、热阻与极限功率等性能的影响进行研究.结果表明:充液率对丙酮热管的温差变化影响较大,在相同情况下,丙酮热管需要更高的充液率.乙醇热管的温差性能较差,但充液率小的乙醇热管其热阻较小.水热管的极限功率最高,且在100%的充液率时,有着最为良好的传热性能,较另两种工质更适合用于高功率场合.该研究对实际生产和应用中的工质选择有着重要的参考意义.     

微沟槽热管拉削成形工艺及其传热性能研究

提出一种热管内表面微沟槽拉削成形方法,利用多齿拉刀在铜管内表面的挤压作用加工出具有连续翅结构的微沟槽,并通过实验研究了微沟槽热管的启动性能、等温性能以及不同倾角下传热功率.结果表明:拉削成形微沟槽热管在约(15～20)s内实现启动,具有快速热响应能力;热管还具有良好的等温性能,蒸发段和冷凝段的温差较小;热管内真空度对热管传热性能有很大的影响;热管在重力辅助条件下传热功率最大,水平放置时次之,反重力状态下传热功率最差.     

桥管缩径工艺的改进

介绍在液压机上进行桥管缩径工艺及模具的改进,运用改进后的工艺及模具压制桥管,提高了产品合格率和模具使用寿命。     

微沟槽热管传热性能实验研究

为研究充液率、真空度和长度对热管传热性能的影响作用,利用基于虚拟仪器技术的热管传热性能测试平台对直径6mm的微梯形沟槽热管在不同充液率、不同真空度以及不同长度等条件下进行实验测试.实验表明:微沟槽热管的最佳充液率在(75～100)%之间.热管内必须具备足够低的真空度,且充液率需根据真空度的不同适当调整.热管长度缩短可以提高其传热性能,但长度较短时,需适当提高充液率.     

微沟槽热管充液旋压成形实验研究

对微沟槽热管充液旋压成形工艺进行了研究,通过试验对影响充液旋压成形加工的三种关键性因素进行了研究与分析.结果表明,在影响充液旋压加工沟槽式热管的三种因素中,旋压当量直径和刀具与滚珠间相对位置主要影响热管内微沟槽形状和尺寸大小,如槽深、槽宽和深宽比;刀具与滚珠间相对位置和拉伸速度影响充液旋压加工过程中铜管是否被拉断;拉伸速度对热管表面粗糙度影响很大.     

薄壁圆杯缩径工艺方案的优化设计

采用薄壁圆杯缩径成形工艺生产汽车产品是一种新技术.与薄壁管缩径比较,缩径时存在着口部起皱、圆筒壁和项盖弯曲失稳的缺陷.为了得到高质量的产品,缩径工艺方案设计要考虑材料性质、摩擦系数、缩径变形量、模具参数等诸多因素.以汽车后弹簧座缩径成形为例,研究了上述参数对缩径工艺方案设计的影响.并分别采用近似理论解析和有限元数值模拟两种方法进行工艺方案的优化设计,得到了应用于实际的工艺方案.相比而言,有限元模拟设计的工艺方案,可以得到更少的工序次数,并缩短了工艺开发周期,成本更低,生产效率更高.     

5.4MN管材压头缩径液压机缩径原理分析

本文介绍了洛阳工学院研制的压头缩径液压机的技术经济特性及适用范围,在该设备上实现管材多向变形缩径的基本原理及受力分析,并通过实践得到验证。     

Analysis of collapse in flattening a micro-grooved heat pipe by lateral compression

The collapse of thin-walled micro-grooved heat pipes is a common phenomenon in the tube flattening process, which seriously influences the heat transfer performance and appearance of heat pipe. At present, there is no other better method to solve this problem. A new method by heating the heat pipe is proposed to eliminate the collapse during the flattening process. The effectiveness of the proposed method is investigated through a theoretical model, a finite element(FE) analysis, and experimental method. Firstly, A theoretical model based on a deformation model of six plastic hinges and the Antoine equation of the working fluid is established to analyze the collapse of thin walls at different temperatures. Then, the FE simulation and experiments of flattening process at different temperatures are carried out and compared with theoretical model. Finally, the FE model is followed to study the loads of the plates at different temperatures and heights of flattened heat pipes. The results of the theoretical model conform to those of the FE simulation and experiments in the flattened zone. The collapse occurs at room temperature. As the temperature increases, the collapse decreases and finally disappears at approximately 130 ℃ for various heights of flattened heat pipes. The loads of the moving plate increase as the temperature increases. Thus, the reasonable temperature for eliminating the collapse and reducing the load is approximately 130 ℃. The advantage of the proposed method is that the collapse is reduced or eliminated by means of the thermal deformation characteristic of heat pipe itself instead of by external support. As a result, the heat transfer efficiency of heat pipe is raised.     

煤气层管道切割装置的研究设计

煤矿井下不可避免存在瓦斯,如何安全可靠地切割井下金属、非金属器件已经成为一个重要课题.作者利用井下综采设备的液压资源,研制一种液压马达锯.对马达锯的运动形式、结构形式进行研究,确定合适的工作参数,使马达锯在作业时不产生火花、温升.同时,对马达锯的操作、夹持机构进行研究,力争达到轻便、灵活,适于井下作业.     

强化传热微沟槽圆管压扁变形过程研究

对内壁具有螺旋V型微沟槽的圆管进行连续加载压扁试验,分析比较了硬、软态微沟槽圆管的压扁变形过程及力学性能.结果表明:硬态沟槽管压扁过程中会依次产生"一次塌陷"、中闻折痕、"二次塌陷"等严重截面畸变;软态沟槽管压扁变形比较均匀,截面畸变程度较小,环向刚度较小,能够在较小的压缩载荷下实现压扁成形.     

Development of hybrid loop heat pipe using pump assistance for cooling application on high heat flux device

Loop heat pipe (LHP) is an effective two-phase heat transfer device that utilizes evaporation and condensation of a working fluid. LHP is widely used in a passive cooling system, highly reliable and a very high thermal conductive device. However, extreme power density can cause dry-out in the evaporator section of LHP and might hinder the performance of the cooling system. The purpose of this research is to design and manufacture a new prototype of LHP by modifying the conventional LHP. The modification was performed by adding a diaphragm pump, called hybrid loop heat pipe (HLHP). The experimental results show that the installation of pumps in the modified LHP was able to prevent the occurrence of a dry out and reduce the operating temperature. Under a constant conductance mode, the pump was activated for 20 minutes and succeded in forcing the system to a new stable condition with a significant temperature drop. These results indicate that HLHP is very promising as a two-phase cooling system that can be proposed for devices that produce high heat flux.

     

高强度钢质管道切管机坡口装置的研制

围绕X70、X80高强度钢质管道端口的坡口作业,分析了管道管端坡口作业的国内外技术现状,介绍了管道切管机坡口装置的组成及工作原理,设计了仿形坡口刀架部件和固定挡块部件的结构。通过现场试验,用仿形坡口装置能加工出完全符合钢质管道焊接标准的精确焊接坡口和一致钝边。     

负压下热管管外降膜蒸发的换热特性研究

热管作为一种高效的传热方式,以其优良的传热性能在工业生产的不同领域中得到了广泛应用.根据流体边界层理论,研究了负压下热管管外降膜蒸发过程中速度边界层和热边界层的形成规律,给出了速度边界层和热边界层厚度的计算函数.在此基础上得到了该模型下热管管外降膜蒸发换热系数的计算方法,推导出相关的计算公式.分析了真空度、喷淋负荷以及传热温差等对热管管外降膜蒸发传热性能的影响,为热管在负压下管外降膜蒸发的工程应用和研究提供了指导.     

基于磁法的油管接箍检测研究

油管接箍检测装置是实现不压井作业过程中对油井保压密封的核心环节。采用磁法检测原理研制的螺旋电感线圈可准确检测到油管接箍的位置,依此控制环形防喷器的动作。既保证胶芯不被损坏,又保证井口密封。首先借助Ansoft电磁场有限元分析软件,分析了电感线圈的参数对检测效果的影响规律。包括电感线圈的骨架高度、骨架内径、线径大小、匝数。试制电感线圈并试验验证了仿真结果的准确性。     

A study on the heat transfer characteristics of a self-oscillating heat pipe

In this paper, the heat transfer characteristics of a self-oscillating heat pipe are experimentally investigated for the effect of various working fluid fill charge ratios and heat loads. The characteristics of temperature oscillations of the working fluid are also analysed based on chaotic dynamics. The heat pipe is composed of a heating section, a cooling section and an adiabatic section, and has a 0.002m internal diameter, a 0.34m length in each turn and consists of 19 turns. The heating and the cooling portion of each turn has a length of 70mm. A series of experiments was carried out to measure the temperature distributions and the pressure variations of the heat pipe. Furthermore, heat transfer performance, effective thermal conductivity, boiling heat transfer and condensation heat transfer coefficients are calculated for various operating conditions. Experimental results show the efficacy of this type of heat pipe.     

整体翅片叉排热管散热器的传热特性研究

针对三维坐标系下,整体翅片叉排热管散热器的流动和传热特性进行数值模拟研究.分析了四个主要影响因素:翅片间距、翅片厚度、排间距和管排布对努塞尔数、流动摩擦因数和热阻的影响.管排布分别为4-3叉排和3-2叉排,翅片间距分别为6mm、7mm和8mm,翅片厚度分别为0.8mm、1mm和1.2mm,排间距分别为20mm、24mm和28mm.计算结果表明:随着翅片厚度的增加,摩擦因数减小,换热能力增强,热阻有所上升;随着翅片间距的增大,摩擦因数增大,换热能力提高,而热阻基本为增加趋势;当热管排列方式从4-3叉排变为3-2叉排后,摩擦因数增加,但Re较大时,摩擦因数趋于相同,换热能力明显下降,但热阻呈下降趋势.