Numerical investigation on the thermal-hydraulic performance of helical twine printed circuit heat exchanger

The printed circuit heat exchanger (PCHE) is a high-efficiency heat exchanger with high compactness, pressure resistance, and stability. It can also withstand high temperatures and ultra-low temperatures. Therefore, it has attracted a large number of scholarly interests in recent years. In order to improve the thermal and hydraulic performance of traditional printed circuit heat exchangers, a three-dimensional helical twine printed circuit heat exchanger (HTPCHE) is designed and the laminar flow is numerically investigated using water as the working fluid. Taking Colburn factor j, Fanning friction factor f and comprehensive index j/f as parameters, the thermal-hydraulic performance of HTPCHE and zigzag-type PCHE with different inclined angles are compared. It is found that when the inclination angle of HTPCHE is 10-25 degrees, its overall performance is better than that of traditional PCHE. When the inclined angle is 10 degrees and Re-in = 828, the overall performance is 37.6% better than that of 15 degrees zigzag channel. In addition, the impact of the pitch of HTPCHE and the thickness of the transition plate on its heat transfer and flow characteristics is explored. It is discovered that when the given fixed inclined angle, the overall performance can be improved by increasing the pitch while the thickness of the transition plate does not have any significant impact.