WINDOWS-BASED PORTABLE LABORATORY SYSTEM FOR DEMONSTRATING HEAT TRANSFER FROM AN EXTENDED SURFACE

摘要

An Armfield~(TM) small bench top service unit (HT10X) in conjunction with an extended surface heat transfer assembly (HT15) are utilized to demonstrate the temperature profile and heat transfer characteristics of a cylindrical rod. Heat flows along the rod by conduction and is lost to the surroundings by combined natural convection and radiation. This well-instrumented laboratory teaching equipment allows students to measure the temperature distribution along the rod and compare the result with a theoretical analysis. Also, heat transfer from the extended surface resulting from the combined modes of free convection and radiation heat transfer is investigated. A self-contained Windows-based data collection and analysis system has been developed for automating all the manual functions of the Armfield? extended surface heat transfer assembly; HT15. This system uses an inexpensive plug-in data acquisition board to read the voltage signals corresponding to nine K-type thermocouples and heater supplied voltage and current. The user interface software that is written in Visual Basic 6 uses 32-bit libraries to control the heater voltage and read the thermocouples voltages and heater supplied voltage and current. Used in conjunction with the HT15 unit, the software is a valuable teaching tool for instructors and provides a comprehensive learning environment within which heat transfer characteristics can be studied. It is aimed at enhancing the students understanding of one dimensional heat conducttion along a cylindrical rod and enabling them to contrast theory and practical measurements of temperatures. It is also the intent of this paper to discuss the successful integration of this educational system into portable instructional technology for the classroom and the mechanical engineering laboratory courses.