Numerical study on flow and heat transfer of high‐pressure syngas in membrane helical‐coil heat exchanger

Numerical simulation was conducted to investigate the flow and heat transfer of high‐pressure synthesis gas (syngas) in an annular channel consisting of membrane helical coils. Effects of radial pitch, axial pitch, and inner helical coil diameter were considered. The numerical results are in a good agreement with our previous experimental results of heat transfer in membrane helical‐coil annular channels. The average heat transfer coefficient of the membrane helical coil decreases to a constant with the rise of radial pitch; meanwhile, it increases first and decreases afterwards with the increase of axial pitch. Although the local heat transfer coefficients of the inner and outer coil are irrelevant to the coil curvature, the average heat transfer coefficient of inner coil is higher than that of outer coil due to the lower finned ratio of inner coil.