Abstract: This paper presented a simple and reliable device system for the measurement of heat transfer coefficient between the immersed tube’s surface and particles in an indirect heating tube rotary dryer，based on analysis of heat transfer process in a tube rotary dryer. A mathematical model to derive heat transfer coefficient from the measured parameters was developed based on the unsteady heat transfer performance. Periodical instantaneous heat transfer coefficient between tube’s surface and particles was observed as the tube rotating with the cylinder. Low heat transfer coefficient was observed at the high position when the tube was immersed in the particle phase. Analysis of error transfer showed that the accuracy of heat transfer coefficient was sensitive to the measurement accuracy of tube surface area，tube’s surface temperature increasing ratio，electric current，temperatures of tube surface and materials. Test results also demonstrated that under the common six operating conditions in this paper，the developed measuring approach yielded high accuracy of heat transfer coefficient with relative error less than 3.5%，and the total measurement error was mainly composed of the error of tube’s surface temperature increasing ratio.

Key words: drying, heat transfer, measurement, indirect heating, tube rotary dryer

摘要： 在对列管回转干燥机内传热过程进行深入分析的基础上，设计了简便、可靠的实验系统，并运用非稳态传热理论导出列管壁面与物料颗粒间的传热系数与被测量参数的关系式，从而建立了一套用于间接加热式列管回转干燥机的加热管壁面与物料颗粒间传热系数的测试方法。实验装置的传热系数测量结果显示，列管壁面与颗粒间的瞬时传热系数随筒体转动呈现周期性的变化规律，随着列管位置的升高，传热系数呈逐渐降低的趋势。通过对测试结果的误差分析表明，对传热系数测量精度影响最大的因素是紫铜管表面积，其余依次为壁面升温速率、加热电流、列管壁面温度和物料温度的测量。对常见的6种运行工况的传热系数测试结果进行了可靠性分析，结果表明，所产生的最大相对误差小于3.5%，壁面升温速率的测量误差是总误差的主要构成部分。

关键词: 干燥, 传热, 测量, 间接加热, 列管回转干燥机