Numerical study of heat transfer and pressure drop characteristics in helical tubes based on OpenFOAM

Abstract

Due to the structural characteristics of the helical tube, centrifugal force complicates the flow boiling phenomenon inside the tube. How to accurately describe and predict the parameter distributions involved in helical tube flow and heat transfer is a concern for scientists. Based on the OpenFOAM, this paper combines the wall boiling model, the interphase model, other closed models with the Eulerian two-fluid model, analysed changes of void fraction, surface heat transfer coefficient, pressure drop with working conditions in the single-phase to nuclear boiling section in the tube. The results show that this solver and the corresponding empirical relational model have the ability to accurately simulate the boiling of the flow in helical tube; In nuclear boiling section at the working conditions of P=4–8 MPa, q = 200–350 kW/m², Re = 66827–89103, The degree of gas-phase buildup near the inner wall surface of the spiral tube decreases with the increase of Re number, increases with the increase of heat flux and pressure, and the ratio of friction pressure drop to total pressure drop decreases with the increase of Re number, heat flux, and pressure by a maximum of 1.4 %, 4.26 %, and 17.35 %. This paper can provide a reference for adding new models and developing new solvers in the OpenFOAM to simulate boiling in helical tube flows.