摘要
为准确测量气体高速流动过程中温度的变化情况,人们对温度传感器的快速响应特性提出了更高的要求.为此,采用直径为30μm的铜丝和康铜丝,利用可控脉冲放电装置焊接制作了T型快速响应热电偶,并测定了热电偶动态响应特性,得到该热电偶时间常数约为40 ms.考虑到热电偶丝对感温结点附近流体状态的影响,以及热电偶的铠装结构对测点附近流场的影响,快速响应热电偶使用新型铠装结构,感温结点裸露,具有更高的可靠性和更好的动态响应特性.
It is important to measure the rapid temperature change of high-speed gas flow using a rapid response temperature sensor in a few special cases. Foreign products can meet the measurement requirements, but they are costly and inconvenient to acquire;domestic products are rare to obtain. For the accurate measurement of rapid temperature changes in high-speed gas flow, there are higher requirements for rapid response characteristics of thermocouples. Rapid response thermocouples differ from regular thermocouples as they must have a fast response speed, good gas-tightness, sufficient physical strength to cope with the impact of high-speed gas, and minimal effect on the original gas flow state.In temperature sensors with rapid response characteristics, the lumped parameter method has been used to analyze the measures to comprehensively decrease the time constant of the thermocouples by analyzing the heat transfer characteristics of their welding joints. Gases with no radiation ability and high temperature flue gas with radiation ability are selected for analysis. The results of these analyses show the diameter of the sensing point and gas flow velocity to be the controllable factors. However, under the condition of a high gas flow velocity, the heat radiation from the flue gas or the inner wall of the flow passage to the temperature sensing point has little influence on the temperature measurement results.Based on the aforementioned analyses, 30 μm copper wire and constantan wire are used to make a T-type rapid response thermocouple. The sensing point is welded by the controllable pulse discharge device. The welding joints(temperature sensing points) are all within 100 μm. The wires and the armor structure may influence the state of gas flow near the sensing point. Therefore, rapid response thermocouples use a new armor structure with an exposed temperature sensing point, which provides them with high reliability and superior dynamic response characteristics.To calibrate the thermocouples, the temperature rise time
作者
纳鑫
谢建斌
徐立新
王良璧
Xin Na;Jianbin Xie;Lixin Xu;Liangbi Wang(School of Mechanical and Electrical Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Railway Vehicle Thermal Engineering of Ministry of Education,Lanzhou Jiaotong University,Lanzhou 730070,China;Lanzhou West Locomotive Depot,China Railway Lanzhou Bureau Group Co.LTD,Lanzhou 730070,China;School of Materials Science and Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2019年第31期3223-3231,共9页
Chinese Science Bulletin
基金
国家自然科学基金(51776093)资助
关键词
高速气流
温度传感器
快速响应
热电偶
时间常数
铠装结构
high-speed gas flow
temperature sensor
quick response
thermocouple
time constant
armoured structure atmospheric
