Thermal-hydraulic performance analysis of outward convex corrugated tubes based on skewness and kurtosis

Abstract The optimization of corrugation parameters to obtain better thermal-hydraulic performance is the main work of corrugated tube design. In this work, a novel idea is proposed to optimize corrugation parameters based on roughness parameters of skewness (Rsk) and kurtosis (Rku). For this purpose, the CFD numerical simulation is adopted to study the effects of corrugation width, pitch and depth on flow and heat transfer performance, and the effects of corrugation parameters on Rsk and Rku are analyzed. The relationship between roughness parameters and thermal-hydraulic performance is discussed. The results indicate that the corrugated tube has better heat transfer performance than that of the smooth tube because of the corrugation induced recirculation flow and improved flow mixing. In addition, the thermal-hydraulic performance enhancement factor (PEC) of corrugated tube is better with the decreasing of Rsk and Rku. The smaller Rsk and Rku can be obtained by increasing corrugation width and depth and decreasing corrugation pitch. Hence, the research results initially confirm the feasibility of evaluating the influence of single corrugation parameter on thermal-hydraulic performance based on Rsk and Rku.