基于热成像的粮食干燥换热器圆桶壁热阻测试

Thermal Resistance for Cylindrical Wall Structure of Grain Drying Heat Exchanger Based on Thermal Imaging

换热器是粮食烘干领域常用设备之一,其换热效率的高低将直接影响粮食烘干的质量及粮食烘干的成本,而换热器传热阻会间接影响换热器的换热效率。在测定换热器传热阻时,使用传统的接触式热阻测试方法对旋转换热器的多层圆桶壁进行热阻测试存在操作复杂、操作时间长及测试环境要求高等问题。为此,采用先进的热成像技术,对粮食干燥用气相旋转换热器进行了多层圆筒壁结构热特性参数的测量,得到了基于热成像法及传统的接触式测量方法下的旋转换热器多层圆桶壁的特征温度值参数,并以此数据为基础计算了旋转换热器多层圆桶壁的测试值,与实际理论值比偏差小于20%。综合比较两种方法可知:热成像法操作简单、方便,更适合于旋转换热器多层圆桶壁传热阻值的热性能测量。

Heat exchanger is one of the commonly used equipment in the field of grain drying.The heat exchange efficiency of heat exchanger will directly affect the quality of grain drying and the cost of grain drying.The heat transfer resistance of the heat exchanger will indirectly affect the heat exchange efficiency of the heat exchanger.When determining the heat transfer resistance of the heat exchanger,the traditional contact type thermal resistance test method is used to test the thermal resistance of the multi-layer barrel wall of the rotary heat exchanger,there will be problems such as complicated operation,long operation time and high test environment requirements.This paper will refer to advanced thermal imaging technology.The thermal characteristics of the multi-layer cylindrical wall structure were measured for the gas-fired rotary heat exchanger for grain drying.The characteristics of the multi-layered drum wall of the rotary heat exchanger based on the thermal imaging method and the traditional contact measurement method were obtained.Based on the data,the temperature value parameter is calculated based on the data,and the deviation between the test value of the multi-layer barrel wall of the rotary heat exchanger and the actual theoretical value is less than 20%.The two methods are comprehensively compared.The thermography method is simple and convenient to operate,and is more suitable for the thermal performance measurement of the heat transfer resistance of the multi-layer barrel wall of the rotary heat exchanger.