轴承感应拆装中工件内电磁场模型的建立及计算机仿真

在研究轴承内环感应拆装的基础上,建立了感应加热过程中工件内电磁场和涡流分布的基本方程。通过MATLAB软件对被加热工件进行了电磁场和涡流分布的计算机模拟,形象描述了工件内电磁场的分布规律,证明了集肤效应的存在,为轴承感应拆卸装置的设计研究提供了理论依据。通过对感应加热过程中轴承内环内外表层温度的测试,间接证明了所建模型和计算机仿真的正确性。     

感应透热的温度均匀性

本文介绍了金属在感应加热时工件升温的特点和规律,从理论上分析了工件产生径向和轴向温差的原因,提出了改善工件径向和轴向温度均匀性的各种措施。     

基于ANSYS的锻件感应加热温度场的数值模拟研究

针对感应加热过程中工件温度难以测量的问题,应用电磁学和传热学基本理论,建立了锻铸坯料电磁场和温度场分布的数学模型,运用ANSYS软件对感应加热过程温度分布进行变参数研究,为揭示铸坯感应加热过程的规律、优化工艺参数提供理论依据。     

感应加热中的节能途径与措施

本文简述了感应加热的基本原理及高频电流的基本特性，进而引出感应加热的节能方向。和一般火焰加热炉一样，减损增效仍然是感应加热节能中要解决的基本问题，也是指导采用何种节能措施的依据。文中提出了六点节能措施。文中最后把感应加热法与一般燃料炉从理论和实践上进行了节能对比，指出了感应加热不仅工件加热质量好，而且可以较大的节约能源。     

高频感应加热设备感应器的设计与制造

高频感应加热设备感应器的设计与制造感应加热表面淬火是通过感应器来实现的，表面淬火的质量及设备的效率和利用率，在很大程度上都取决于感应器的设计与制造。感应器的工作原理感应器的作用是将高频功率发生器产生的高频能量以高的效率向被加热工件传输，由实际工作时，...     

感应加热线圈内径可变型淬火回火设计开发

传统的高频感应加热淬火回火设备要根据工件的形状、尺寸、用途制作专用的加热线圈。无疑,这种方式对于不同处理工件要更换、设计制做不同的感应加热线圈必然导致生产成本高、生产效率低等缺点。介绍了日本电气兴业株式会社新研制开发的无接点式感应加热线圈内径可变式感应加热线圈的结构、内径可变机理与优越性。     

高频感应加热过程的负载电气特性分析

高频感应加热系统由于它的独特优点,已广泛应用于工业生产中。介绍了高频感应加热电源系统的特点,分析了感应加热的集肤效应特性,给出它的电感性负载阻抗理论模型,最后实验验证了在不同温度下,负载的电感与电阻随温度变化趋势,证实了理论分析结论。     

利用感应加热和碳氮共渗烧结处理后工件的性能

近年来金属粉末件感应加热烧结工艺得到了工业应用。本文着重研究感应加热温度和碳氮共渗温度对工件组织和性能的影响,工件是用铜、铬、镍合成的石墨铁粉冷压而成。作者用履带式拖拉机行程系统     

感应加热的电磁力分析

本文较系统地、定性地对感应加热中的电磁力问题进行了论述和分析。在研制感应加热设备时,电磁力对感应器、工件和传动机构作用等应作充分考虑,并应采取相应的措施。     

高频感应加热

高频感应加热系频率为数kHz～数GHz的一种电磁波加热。其主要是利用电磁感应的作用在金属材料产生磁滞损耗以及涡电流损失的热能来加热工件的。高频加热又分为介质加热和微波加热2种加热方式。简述了高频加热的处理。着重介绍了高频介质加热的特点，加热用振荡电源设备及其在树脂成形预热、硬化处理、薄膜粘结、材料干燥、食品保鲜、医疗等方面的应用。     

基于单片机控制的微波加热系统

介绍了以AT89C52单片机为控制核心的微波加热系统,通过PID算法对测量数据和设定数据进行处理,通过控制单相交流调压模块控制磁控管的功率,从而控制炉子的温度。用K型热电偶来检测炉子的温度。该微波加热系统加热物体效率高,而且物体受热均匀。     

Lifetime commissioning as a tool to achieve energy‐efficient solutions

Quality control of the complete energy system is necessary if energy‐efficient solutions are to be met. To perform good building operation and quality control of a given system, it is necessary to have information about building systems and assessment tools. The paper presents Norwegian lifetime commissioning (LTC) procedures that are enabling follow‐up of the building performance during the building lifetime by establishing a generic framework on building performance data. Further, three developed assessment tools are presented: inspection algorithm for ventilation system, mass balance inspection algorithm for consumer substation, and advanced method for improved measurement of heat pump performance based on data fusion technique. The LTC procedures were tested on two case buildings. The results showed that 20% of all the defined building performance data can be monitored by BEMS. Using the mass balance inspection algorithm, it was found that fault in mass balance prevented implantation of desired temperature control for floor heating system. For heat pump performance, measurement of differential water temperature can be very erroneous. Hence, use of compressor electrical signal can give more precise data on heat pump performance. Comparative analysis showed that detailed monitoring system helps tracking energy use and fault detection in operation. Yearly and hourly profiles of energy consumption with separated use and energy carriers are given in the paper. Copyright © 2011 John Wiley & Sons, Ltd.     

新型模糊控制器在感应加热温度控制中的应用研究

针对感应加热电源温度控制,采用了一种新型模糊控制控制器,介绍了基于该模糊控制的感应加热温度控制系统的构成及其设计。通过MATLAB／SIMULINK进行了仿真,仿真结果验证了该温度控制系统的有效性和优越性。     

Anisotropic thermal conductivity measurement of carbon-fiber/epoxy composite materials

This project originated from a need for understanding heat transfer in carbon-fiber/epoxy natural-gas tanks undergoing rapid heating during refilling. This paper presents both experimental and theoretical work concerning evaluation of the thermal properties of carbon-fiber/epoxy composite materials. An effective measurement system was implemented based on steady-periodic heating: a platinum film sputtered on the surface of a sample was periodically heated by an AC current at frequency ω. The phase lag and amplitude data of a voltage signal at frequency 3ω related to the temperature response information in the platinum film were collected from the experiment. An impedance analysis model was employed to convert the phase and amplitude of the voltage to those of the temperature response. The anisotropic thermal properties were deduced from an inverse parameter estimation model, which was a least-square systematic comparison between experimental data and the theoretical model. The anisotropic theoretical solution was derived based on the Green’s function solution. Poly(methyl methacrylate) (PMMA) samples were used as reference samples to verify the measurement system. Both in-plane and through-thickness thermal conductivity of carbon-fiber composite samples were obtained and presented simultaneously.     

基于单片机的电磁感应轴承加热控制器设计

电磁感应法加热轴承是轴承装配过程中使用的一种主要方法.设计了一个基于单片机的轴承加热控制器,采用K型热电偶和MAX6675进行温度的测量,通过双向晶闸管控制线圈有效电压进行加热,通过同步脉冲产生电路,通过软件设计控制晶闸管的导通角,实现了轴承的退磁.实际应用表明,本控制器能够高效、快速地完成轴承的加热,并将轴承的剩磁限制在3.0奥斯特以下.     

An intelligent system for the climate control and energy savings in agricultural greenhouses

A greenhouse for crop production is a complex thermodynamic system where the indoor temperature and the humidity conditions have a great impact on the crop yields. This system can be considered a multivariable input output system MIMO. This paper aims at presenting a physical model of a greenhouse, experimentally validated, in order to propose a fuzzy-based controller to manage the indoor climate of a greenhouse using some actuators (induction motors, heating system etc.…) for ventilation, heating, humidifying, and dehumidifying purposes. In addition, a novel approach is presented for energy management by involving the photovoltaic energy in order to minimize the use of conventional electrical grid and to lower costs of agriculture production. The photovoltaic (PV) generator will serve to power a direct torque control (DTC) controlled induction motor which drive a variable speed fan. The validation of the physical model shows a high agreement with the experimental measurement. The simulation results show the effectiveness of the fuzzy controller as well as the PV generator for saving the energy and lowering the costs of crop production into greenhouses.     

应用极性相关技术在线测量高温烟气流动速度

应用单片微机ＭＣＳ５１系列及自行开发的扩展系统研制的测量系统，成功地对管道内高温烟气流速进行了在线测量，该系统采用新颖的过零时刻采样法和过零时刻算法对烟气流动噪声信号作极性相关处理，快速搜寻峰值对应的时延值，并据此求得测量速度。试验表明，测量技术具有测量精度高，测量时间短，且可靠性强，适于工业现场进行在线测量。     

PHOTOTHERMOELASTIC MEASUREMENT BY MEANS OF HIGH FREQUENCY INDUCTION HEATING APPARATUS

In this paper, the high frequency induction heating apparatus developed by the authors to analyze thermal stresses by means of photoelastic experiment is described, and the accuracy of the apparatus is examined. The photoelastic experiment for the hollow disk with a concentric circular hole in steady-state temperature distribution under heating conditions in a vacuum of 50°and 0° on the inner and outer edges, respectively, is performed to confirm the reliability of the apparatus. For the purpose of the realization of the heating conditions, the cooling system that circulates the cooling medium is incorporated into the high frequency induction heating apparatus. The experimental and theoretical values are compared.     

大型曲轴感应加热过程的有限元分析

依据感应加热理论,建立了有限元计算温度模型。并以此分析研究了12V240机车曲轴坯弯曲镦锻前的感应加热过程,得到了坯料内的温度分布状况以及温度随时间的变化规律。经与现场实测值进行对比,证明了所用算法的正确性。从而为改进曲轴坯感应加热工艺提供了可靠的依据。     

Comparison between single- and multiple-zone induction heating of largely curved mold surfaces

This study applied three-dimensional steady-state finite-element numerical simulations of electromagnetic fields and temperature distributions to evaluate the effects of various coil geometries, regional depositions, and magnetic shielding materials on the induction heating of a curved mold plate surface used for fabricating automotive spoilers. Conventionally, the induction heating of large mold surfaces by using a set of long inductive coils entails employing a costly, high-power induction heating device. This study proposes a multizone induction heating approach that entails dividing a target surface into several zones and then applying numerous sets of short inductive coils that require only low-power induction heating devices to the individual regional zones for heating. In this approach, the coil design is relatively simple for efficiently heating these small-area zones. The simulation results are described as follows: (1) the geometry of the inductive coils with respect to the processed workpiece demonstrated a considerable effect on the electromagnetic field distribution and the heating efficiency of the system. (2) Magnetic shielding materials facilitated eliminating the proximity effect, which produces a nonuniform heating pattern along the workpiece wall. (3) Compared with single-zone induction heating, the multiple-zone induction heating of a largely curved mold surface enhanced the heating rate and uniformity performance.