微火焰温度场的自动扫描微型热电偶测量

Temperature Field Measurement of Micro Flames Using Auto-Scanning Micro Thermocouple

探索了一种用微型热电偶自动点扫描测量微火焰温度场的方法,从理论上分析了热电偶大小与热气流速度对测温误差的影响,并以3个直列预混微火焰为对象,通过实验详细考察了自动扫描热电偶的数据采集时间间隔和热电偶移动速度对火焰温度测量的影响.结果表明:当丝径小于50μm时,微型热电偶测量的火焰温度误差将小于0.6%;实验中采用丝径50μm的R型微型热电偶,当温度数据采集时间间隔为0.1s和热电偶移动速度为1.82~4.22mm/s时,自动扫描测得的火焰温度与手动单点长时间停留热电偶测得的温度场一致;微型热电偶自动扫描方法可实现快速、准确的微火焰温度场测量.

Proposed in this paper is a method to measure the temperature of micro flames using an auto-scanning micro thermocouple. In the investigation, first, the effects of thermocouple size and hot flue gas velocity on the measurement error are theoretically analyzed. Next, the effects of data acquisition time interval and thermocouple moving velocity on the measured flame temperature are explored in detail by the experiments of three linearly- arranged micro premixed jet flames. The results show that the temperature measurement error is less than 0.6% when the wire diameter of micro thermocouple is less than 50 p,m, and that, when the data acquisition time interval of auto-scanning is greater than 0.1 s and when the moving velocity of thermocouple ranges from 1.82 to 4.22 mm/s, the temperature measured by a 50-p^m auto-scanning micro R-thermocouple coincides well with that by the manual single-point long-time measurement, which means that the proposed auto-scanning micro thermocouple method helps to measure the temperature of micro flames rapidly and accurately.