An innovative tetramerous heat blade device for double pipe heat exchangers: An experimental study

Heat pipes are renowned for their exceptional ability to efficiently conduct heat energy. In this study, we leverage this inherent capability to create an innovative flow turbulator aimed at enhancing the convection rate within a double pipe heat exchanger. We prioritized the simplicity of the turbulator and its flexibility to be redesigned for different sizes of heat exchange pipes, thereby extending its practical applications. The proposed device comprises four mini-sized rectangular heat pipes, named "heat blades" due to their shape. Each heat blade consists of a hollow copper shell containing two pieces of copper foam, serving as the wick. Acetone is employed as the base fluid within the heat blades. These heat blades are meticulously soldered around a copper base-ring. We manufactured and investigated devices with three different blade angles (0, 45, and 90). Four devices of each blade type were strategically soldered onto the inner pipe of the double pipe heat exchanger. We explored two distinct configurations: the + -form and x -form arrangements. The proposed turbulator significantly impacts the heat exchanger's thermal behavior, enhancing the overall heat transfer rate by up to 50%. This results in a thermal performance criterion ranging from 1.18 to 1.3, varying with different parameters. Comparing turbulators with different blade angles reveals that devices with a 90 degrees blade angle offer the best convection enhancement. However, considering the associated increase in pressure drops, the device with a 45(degrees) blade angle demonstrated the best overall performance. It is observed that the + -form configuration slightly outperformed the x -form configuration.