Enhancement of Heat Transfer Characteristics by Inserted Novel Turbulators in Circular Tube Heat Exchanger

An experiment is proposed to improve the thermal characteristics of a circular tube heat exchanger by inserting novel and perforated geometric turbulators.Experiments were conducted for three types of turbulators (Td 40 mm, Td 30 mm, and Td 20 mm), two pitch ratio (PR) = L/D 3.1 and 4.28 and Reynolds number range of 13968-30268.Experiments were conducted first for the smooth tube without inserting turbulators.The experimental results revealed that the turbulators improved the thermal characteristic with an increase of 143%, 155%, and 167% for the Nusselt number and an increase of 138%, 143%, and 151% for the friction factor at pitch ratio of PR=3.1.The thermal characteristics factor for each configuration was also determined to be more than unity, with the highest value achieved at PR=3.1 was =1.47.According to the obtained outcomes, the empirical correlations for Nu and friction factor were calculated.