空气焓差法测试空调器性能的影响因素

空气焓差法是空调器性能测试的普遍方法,具有测量周期短、操作简单以及设备造价低等优点。影响空调器性能测试结果的因素主要有取样风速、湿球温度和风量等,因此有必要对其进行有效分析。     

风冷热电空调器的实验研究

介绍了作者研制的风冷热电空调器及其性能实验;研究了热电空调器冷热端之间隔热层最佳厚度、空调器冷端进风量变化以及组成热电空调器的制冷器的不同排列形式对空调器性能的影响.     

风冷热电空调器实验研究

介绍了新研制的风冷热电空调器的性能实验研究,包括热电空调器冷热端之间隔热层最佳厚度、空调器冷端进风量变化以及组成热电空调器的制冷器的不同排列形式对空调器性能的影响。并根据实验结果找出其变化规律,为该种空调器的优化设计奠定基础。     

行车空调热工性能试验空气流量测量装置设计

根据高温行车空调器热工性能测试的特殊要求,提出了一套适用于空气焓值法试验系统的空气取样及流量测量装置设计方法,讨论了取样风机、温湿度测量箱、空气接收混合箱和循环风量测量箱的设计问题。该方法在提高特种空调热工性能测试精度方面作了一些尝试。     

一种新型房间空调器室内温度分布的CFD研究

设计了一种顶部45°角送风的新型房间空调器,对常规送风与顶部45°角送风方式的空调分别建立三维CFD模型对室内温度分布进行模拟计算。结果表明:相比于常规送风方式,顶部45°角送风室内温度分布均匀性显著提高,舒适性增强,达到相同的室内平均温度,其所需的送风量减小50%左右,节能约30%。模型模拟计算结果与试验测量值吻合度高,对设计开发新型室内空调器和优化室内气流组织具有指导意义。     

家用复合式空调器运行特性的模拟研究

利用家用复合式空调器的数学模型对复合式空调器在制冷兼制热水模式、单独制热水模式以及制热兼制热水模式下的运行特性进行了数值模拟,分析了在制冷兼制热水模式下,风冷冷凝器风量和热水流量对系统性能参数的影响,研究了在单独制热水模式和制热兼制热水模式下,生活热水温度和流量对室内制热效果及系统运行稳定性的影响,并提出了相应的解决措施.研究成果可为进一步开发这种节能型的家用复合式空调器产品奠定理论基础.     

一种面向用户的计算机集成热工测控系统的研制

良好的测控手段和用户友好的测试软件是高精度的空调器性能测量装置的重要保证.本文分析了影响空调器测量精度的影响因素,设计了一套用于空调器性能测量的测控系统.测控系统以面向用户为设计原则,在保证测量精度的前提下,采用了高性能的测量传感器、自动控制器、人机对话的触摸屏等,编制了关键的控制采集软件,具有控制精度高、使用灵活、界面友好、性能稳定可靠等特点,在多套空调器性能测量装置上成功应用.     

全截面防堵阵列式风量测量装置的设计和应用

结合潮州发电厂1 000 MW机组风量测量装置的改造过程,对全截面防堵阵列式风量测量装置的原理、工作特点进行了分析,为磨煤机进口一次风量测量装置的设计、标定、安装提供了参考。     

风量测量装置的量程修改

本文针对投运中的发电机组,由各种原因引起的风量测量装置选型与实际工况不符,造成风量无法准确测量,进而影响运行人员风量调整的现象.结合生产中的实际情况,对风量测量装置的量程进行了修改,效果较好.希望能给遇到同类问题的朋友予以参考.     

风量罩的新型校准方法研究

基于航空航天、气象暖通、节能环保等各个领域对风量罩的使用需求及测量精度要求不断提高,但国内目前没有统一的校准规范及检定规程,对风量罩的溯源链条不够清晰,介绍了一种新的风量罩校准方法,主要是利用标准皮托管、差压传感器、游标卡尺和风洞作为风量标准装置开展风量罩校准工作,校准时,风洞提供气流环境,皮托管和差压传感器测量得到风速值,游标卡尺测得风洞口径,进而计算得到风洞截面积,风速值与风洞截面值的乘积即为标准风量值,标准风量值与被校风量罩的示值相差即为示值误差。介绍了风量罩的校准原理及校准方法,并根据数学模型对其扩展不确定度进行分析,评定结果可达到1.7%,符合风量罩的使用要求。结果表明,该套风量标准装置使用方便,操作简单,测量精度高,不确定度小,可作为一套标准装置对风量罩开展计量校准工作。同时提升了风量测量的准确性和可靠性,满足了航空航天、气象暖通、节能环保等各个领域生产和使用过程中对风量的高精度要求。     

基于湿含量计算模型的管道空气流量在线微机测量系统

空气测量准确性对热工设备燃烧效率、热效率以及气氛控制有非常重要的影响。湿空气中水蒸汽含量对空气测量准确性有较大的影响。随着节能工作的日益加强，对助燃用空气测量准确性提出了更高要求。针对目前管道空气流量在线测量系统测量精度较低和控制滞后的问题，本文基于蒸汽压方程，建立了工况下管道空气流量测量新模型和在线测量系统，实现了管道空气流量的完全在线测量，提高了测量的精度和速度。本测试系统已成功地应用于生产实际，取得了较好的节能效果。     

基于全方程热流控制方法的典型舱段加热烧蚀试验研究

烧蚀型热防护是高超声速飞行器应用最广泛的一种热防护形式,高温烧蚀理论及相关计算分析方法尚不完善,无法通过计算给出精确的烧蚀热防护系统的热流和温度时序.全方程热流密度控制试验模拟结构的真实飞行历程,计及气动加热与结构热响应的耦合效应并实时测量迭代,成为烧蚀型热防护系统性能测试和研究的重要措施.本文以典型舱段为试验研究对象...     

A direct integration approach for the estimation of time-dependent boundary heat flux

In a one-dimensional heat conduction domain with heated and insulated walls, an integral approach is proposed to estimate time-dependent boundary heat flux without internal measurements. It is assumed that the expression of the heat flux is not known a priori. Hence, the present inverse heat conduction problem is classified as a function estimation problem. The spatial temperature distribution is approximated as a third-order polynomial of position, whose four coefficients are determined from the heat fluxes and the temperatures at both ends at each measurement. After integrating the heat conduction equation over spatial and time domain, respectively, a simple and non-iterative recursive equation to estimate the time-dependent boundary heat flux is derived. Several examples are introduced to show the effectiveness of the present approach.     

基于称重法的水暖流量测量系统

为解决现有水暖产品流量测量装置性价比低、测量稳定性差的问题,本文通过介绍称重法流量测量系统的组成及其测试原理,说明其流量计算方法,分析流量测量总不确定度并与当前高精度流量计进行对比。结果表明:基于称重法的流量测量系统具有较高的测量精度。基于称重法的流量测量系统在实际运用中具备较高的性价比,值得推广。     

激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）测定锡石样品中微量元素

A method for determination of trace elements in cassiterite by 213 nm laser ablation inductively coupled plasma mass spectrometry with lithium tetraborate flux sample preparation procedure and in-situ focusing has been investigated. The relative deviations of measurement from flux sample preparation procedure and in-situ focusing are less 25% and 10%－120%, respectively.     

Determination of magnetic flux density on the surfaces of rolling-element bearings as an indication of the current that has passed through them—an investigation

This paper introduces a theoretical model to determine the developed magnetic flux density on the inner and outer surfaces of the inner race and outer race, and on the surface of rolling-elements of a rolling bearing operating under the influence of an electric current. The flux density, analytically determined, is compared with that of the flux density developed on the surfaces of races and rolling-elements of bearings tested on the bearing test-up under the influence of an electric current. The magnetic flux density on the surfaces of damaged bearings of motors and alternators has also been measured and the theoretical model is used to determine the amount of current flow through the damaged bearings. The current flow through the bearings, thus established, has been compared with that of the current evaluated by the measurement of shaft voltage and bearing resistance. The model has the potential to ascertain the cause of failure by current passage and to establish the amount of flow of leakage current through the bearings by determining the magnetic flux density on the surfaces of rolling-element bearings. The current flow, thus established, together with the measurement of the shaft voltage, allow the bearing impedance to be established.     

Magnetic Flux Density Distribution on the Track Surface of Rolling-Element Bearings–-An Experimental and Theoretical Investigation

This paper brings out the theoretical model to determine the developed magnetic flux density on the track surfaces of inner race, outer race and rolling elements of a rolling-element hearing operated under the influence of electric current. The flux density, analytically determined, is compared with that of the flux density developed on the track surface of races and rolling elements of the bearings tested on the bearing test-up under the influence of electric current. Also, the residual magnetic flux density on the damaged bearings of motors and alternators has been measured and the theoretical model is used to determine the amount of current flow through the damaged bearings. The current flow through the bearings, thus established, has been compared with that of the current evaluated by the measurement of shaft voltage and bearing resistance.     

Note: Continuing improvements on the novel flat-response x-ray detector

This note describes multi-updates of the novel flat-response x-ray detector in fabrication technology, experimental application, and data uncertainty evaluation. Unlike the previous design, the compound filter is combined into one piece through an improved fabrication process that greatly enhanced its self-supporting capability. A method of pinhole-array imaging is introduced into the experimental application process to stop any debris from the hohlraum and to uniformly reduce the radiation flux. The experimental results show that this method works well. Furthermore, a method of uncertainty evaluation of the radiation flux measurement by the novel flat-response x-ray detector has been developed. The influence of the radiation spectrum to the flux measurement is analyzed. The evaluation shows that the relative uncertainty of the radiation flux is about 10% in higher radiation temperature condition (Tr > 150 eV) and 16% in lower radiation temperature condition (Tr < 100 eV).     

On the interface diffusion coefficient for solving Reynolds equation by control volume method

When using the control volume method to solve the Reynolds equation, the mass flux crossing the control surface should be calculated properly. According to Pantakar’s formulation, which is commonly used in solving general convection–diffusion equations, the mass flux can be expressed as a function of the convection and diffusion coefficients. Consequently, the performance of the numerical algorithm depends strongly on the scheme employed for the calculation of the interface diffusion coefficient. Two diffusion schemes have been proposed in the literature. One scheme (referred to as scheme I) employs the arithmetic mean of the pressure values at the neighboring grid points to evaluate the interface diffusion coefficient, while the other (referred to as scheme II) uses the harmonic mean of the neighbor diffusion coefficients. Scheme I has been used for solving the Reynolds equation successfully. On the other hand, scheme II, while being popular for solving convection–diffusion types of equations when the diffusion coefficient is known, has not been implemented to solve the Reynolds equation for air bearings, in which the diffusion coefficient depends on the unknown dependent variable. In this paper, we implement scheme II for solving the Reynolds equation and compare its performance with that of scheme I. Both numerical and analytical results indicate that scheme II may yield unrealistic results for air bearings with large clearance discontinuities.     

On the dependence of spray momentum flux in spray penetration: Momentum flux packets penetration model

Momentum flux is a very important parameter for predicting the mixing potential of injection processes. Important factors such as spray penetration, spray cone angle, and air entrainment depend largely on spray momentum. In this article, a model is obtained which is able to predict the spray tip penetration using as an input the spray momentum flux signal. The model is based on the division of the momentum flux signal into momentum packets (fuel parcels) sequentially injected, and the tracking of them along the spray. These packets follow a theoretical equation which relates the penetration with the ambient density, momentum, spray cone angle and time. In order to validate the method, measures of momentum flux (impingement force) and macroscopic spray visualization in high density conditions have been performed on several mono-orifice nozzles. High agreement has been obtained between spray penetration prediction from momentum flux measurements and real spray penetration from macroscopic visualization.