Experimental and analytical comparison of internally finned pipe with unfinned pipe for heating applications

Abstract

This paper presents a capstone project that was done by two MET (Mechanical Engineering Technology) students during their senior year at Purdue Polytechnic, Kokomo. The project objective was to build an apparatus that would allow evaluation of pipes performance in transferring heat from an external heating source wrapped around the outer surface of pipes. The considered pipe set included a normal pipe and another with three longitudinal straight fins soldered to the internal side of the pipe. Heating pads were wrapped around the outer circumference of the pipe providing constant heat flux. The heating pads were insulated using fiber glass insulation. The water flow inside the pipe was controlled to supply same flow rate for all tests while achieving hydrodynamic fully developed conditions. Thermal flow conditions were still developing since the aim of the testing section was to check on thermal enhancement with time. Temperature of water inlet, outlet and along the pipes were recorded for the normal pipe (base case) and compared to the internally finned pipe case using thermocouples embedded through the pipe surface into the center core of flow. The experimental results were compared to numerical results. It was found, on average basis that the outlet to inlet temperature difference increases from 5.3 F for unfinned pipes to 9.8 F for 3-fins pipes while increasing the pressure drop by 9%. More discrepancy between experimental and analytical results was found for finned pipes. The difference between calculated and measured values were 4% for unfinned and 11% for 3-fins pipes. Through the implementation of this project, students’ performance and project outcomes were assessed against ABET learning outcomes, such as, (1) applying knowledge, techniques and skills to engineering technology activities, (2) applying knowledge of mathematics, science, and engineering to engineering technology programs, (3) conducting tests, measurements, calibration and improve processes, (4) problem solving skills: ability to identify, formulate, and solve engineering problems, (5) team work skills and (6) effective communication: ability to communicate effectively.