Shell-side thermal-hydraulic performances of multilayer spiral-wound heat exchangers under different wall thermal boundary conditions

• Shell-side flow and heat transfer of a spiral-wound heat exchanger is experimentally studied.
• Effects of three kinds of thermal boundary conditions are numerically investigated.
• The constant temperature thermal boundary condition could be employed for simulation.

The multilayer spiral-wound heat exchanger (SWHX) is used extensively in many industrial fields, but little research on the shell-side thermal-hydraulic performances in SWHXs has been performed. So an investigation on the shell-side flow and heat transfer performances of multilayer SWHXs under turbulent flow is implemented by using experimental and numerical methods. An experiment on the shell-side flow and heat transfer performance of a self-manufactured SWHX with three layers of coils is carried out under heat flux specified boundary condition (BC) to validate a numerical method. The results obtained by the simulations agree well with those from the experiment. Furthermore, to study the effects of different thermal BCs of the tube wall on the shell-side heat transfer performance in the multilayer SWHXs, numerical simulations are performed under the thermal BC of constant heat flux and constant temperature. Then the results are compared to those of the water-to-water conjugate heat transfer. It is found that the maximum relative deviation is 11.4% and 3.5%, respectively. Finally, the correlation of the shell-side Nusselt number, Nus is obtained by the Wilson plot method, which is Nus = 0.179·Res0.862, with the available range of Res from 500 to 3500.