0.9μm光电高温计应用单固定点延伸和多固定点内插的分度方法比较

单固定点延伸和多固定点内插是光电高温计的两种常用分度方法。针对新研制的0.9μm光电高温计进行了这两种分度方法的比较研究。在500~1800℃测温范围内,利用高温黑体炉作比较源,在整百度点与标准光电高温计进行量值验证,结果表明这两种分度方法的温度示值一致性优于0.2℃,与标准值的误差最大不超过0.6℃。两种分度方法的不确定度分别评估为0.2~1.3℃和0.2~0.8℃,k=2。相对于必须测量高温计光谱响应度及其响应度非线性的单固定点延伸方法,多固定点内插法简单并易操作,且不确定度可保持较优水平。该方法无论作为光电高温计的出厂分度还是周期示值校准,均可为大多数温度校准实验室提供参考。     

脉冲加热测量材料热物性技术的综述与分析

使用脉冲热技术测量热物性参数的瞬态量热法克服了利用经典稳态法进行测量的许多缺陷,因而取得了很大的发展.本文介绍了利用脉冲加热技术进行热物性测量的基本原理,简单介绍了最近三十年国内外利用此技术进行热物性测量的原理和装置,以及利用扫描高速高温计进行热膨胀系数和热传导系数测量的方法和实验装置.最后介绍了该领域国内外的最新研究动态和发展方向.     

钨基复合材料烧蚀真温测量

设计制做了氧乙炔焰模拟烧蚀装置 ,运用快速响应的棱镜分光式多波长比色高温计测量了钨基复合材料烧蚀表面的温度 ,并测得材料在烧蚀过程中的快速升温曲线 ,为精确分析材料的动态烧蚀过程和升温热震行为提供了实验基础     

高频焊管焊接点温度的传感及其模糊控制

针对高频焊管焊接区的测温条件 ,采用比色测温仪检测焊接点温度 ,有效地提高了测温信号的稳定性 .应用模糊控制方法调节高频感应电源的输出功率 ,控制焊接温度 ,同时设计了三种调节功能对控制效果作进一步的改善 ,实现了高频焊管温度的稳定控制过程 .     

Application of multispectral radiation thermometry in temperature measurement of thermal barrier coated surfaces

Ceramics coatings are materials widely used in gas turbines to provide thermal shielding of superalloy materials against excessive turbine temperatures. However, measurement of their surface temperatures using conventional radiation thermometers, more so in the presence of high ambient radiation and low emissivity is quite challenging. A multispectral method employing curve fitting technique to measure the temperature of such targets in the range of 800–1200 K and ambient temperature of 1273 K is implemented in this paper through simulation. Several simulated experiments were carried out to identify emissivity models best suited for multispectral radiation thermometry applicable to ceramic coatings. The best emissivity model applicable to yttria-stabilized zirconia of coating thickness of 330 μm in the wavelength range of 3.5–3.9 μm was found to predict temperature with an error of less than 1.5% in the presence and absence of background noise.     

Infrared thermometers for small wires drawing

This work describes the design of two contactless thermometers based respectively on a total radiance and two-color pyrometry scheme, developed to measure the temperature of a small brass coated steel wire during wire drawing. In this critical condition, wire oscillation and relevant insertion errors do not allow using commercial contact or contactless sensors. Thus, ad hoc pyrometers optical layouts have been designed in order to minimize sensitivity to the wire oscillations and emissivity changes. Moreover, performances associated to different infrared detectors have been compared using as figure of merit the achieved measurement uncertainty simulating typical disturbances, i.e. the background temperature variation, the slope of the wire’s emissivity and the effect of the atmosphere transmittance. Finally, the uncertainty budgets were drawn, evidencing the limitations of the proposed methods and identifying the best configuration for both developed instruments.     

Development of a Millisecond Pulse-Heating Apparatus

A millisecond pulse-heating apparatus is presently under development at the Harbin Institute of Technology (HIT). The design is based on systems previously developed both at NIST (U.S.A.) [1, 2] and IMGC (Italy) [3] for the measurement of several thermophysical properties with millisecond time resolution. The apparatus uses rapid resistive self-heating of a strip-shaped specimen from room temperature to a pre-chosen maximum temperature. Power is furnished by a subsecond-duration electrical current pulse through the specimen. Simultaneous measurements are carried out for several quantities. The maximum current is up to 2000 A. Experiments are performed on strip-shaped specimens with the following typical dimensions: 80 mm in length, 10 mm in width, and 1 mm in thickness. The specimen is contained in a large vacuum chamber (bigger than 300 mm in both diameter and height) whose inner wall is coated with a nonreflecting paint. A special designed high-speed pyrometer will be used to measure the temperature of the specimen through one of two quartz windows of the chamber. The heat capacity, the electrical resistivity, the total hemispherical emissivity, and normal spectral emissivity of the specimen are measured by using this apparatus for various materials.     

一种新的多色比色测温方法及系统实现

提出了一种新的多色比色测温方法，研制出基于USB总线的多色比色测温系统。测温系统用内调制光电探测器作为探测单元，能将光信号直接转换为受调制的交流电信号，提高了系统信噪比和处理能力；采用USB数据采集系统，实现了即插即用，传输量大，速度快，实时性好；用PC机对被测体的发射率进行实时近似值的动态处理，有效地提高了测量精度。实际使用表明，在1000℃～1650℃的测量范围内，测温精度达到4‰。     

Graphite Melting and Properties of Liquid Carbon

The results of fast heating (by electrical pulse current) of highly oriented pyrolytic graphite specimens are presented. Experimental data are obtained for graphite melting: the enthalpy of solid and liquid phases under melting, the heat of melting, and the heat capacity of solid and liquid phases near melting. Liquid carbon resistivity is measured under fast heating of cylindrical graphite specimens in thick-walled sapphire capillary tubes. Preliminary data for the isobaric heat capacity C _p for liquid carbon up to 10,000 K and for the isochoric heat capacity C _v up to 8000 K are presented.     

新型精密光电高温计

根据温标传递的特点和需要,设计了新的精密光电高温计。该高温计测量黑体的光谱辐射亮度,结合有效波长原地测量技术,直接依据Planck辐射定律计算被测温度,具备单一参考点分度确定温标的技术能力。该高温计测温范围为800℃～2200℃,在小目标和窄谱带的测量条件下,具有分辨率高、辐射源尺寸影响小、自动化测量等特点。在900℃时温度分辨率为0 01℃。在800℃～2200℃温度范围内,置信水平为0 99时,扩展不确定度为1 0℃～2 4℃。结构参数和性能测试表明,精密光电高温计不仅适用于温度精密测量,而且可作为温标的传递标准。