Prediction of pressure drop and heat transfer coefficient in helically grooved heat exchanger tubes using large eddy simulation

Abstract

Geometry of internally grooved tubes plays a significant role in the performance of heat exchangers. Although there are extensive databases of measurement data for some grooved tubes, it is generally challenging to predict the performance of nonexisting groove shapes. A computational fluid dynamics model based on wall-resolved large eddy simulation of turbulent pipe flow with heat transfer is proposed by using OpenFOAM simulation environment. Fully developed turbulence was simulated by solving the 3D unsteady Navier–Stokes equation in streamwise periodic variables. Simulations for a smooth pipe and a helically grooved tube were carried out at Re = 10,000 to 20,000. Mesh dependency study was performed. Simulation methodology was validated by collating simulated results with literature data and own measurements. The proposed model proved to be accurately predictive: 3.2% to 4.2% difference was found between simulations and measurements. The major novelties of this paper are the introduction of large eddy simulation technique in a new application area, validation for single-phase flow in the given Reynolds number regime, and guidelines for future modellers. This methodology can be used for optimizing parameters of future heat exchanger systems leading to more compact size and better performance.