Numerical investigation on performance comparison of non-Newtonian fluid flow in vertical heat exchangers combined helical baffle with elliptic and circular tubes

•A novel helical baffle heat exchanger with elliptical tubes was developed and tested.•Heat transfer performance in the elliptical tube heat exchanger was numerically studied.•Performance comparison of elliptical tubes with circular tubes was investigated numerically.•Elliptic tube can effectively improve the heat transfer performance.•The correlations for Nu and f in the shell side of the elliptic tube heat exchanger were proposed.