Experimental study on local heat transfer and hydrodynamics with single tube and tube bundles in an external heat exchanger

External heat exchangers (EHEs) are widely used in many industrial fields for heat absorption, such as circulating fluidized bed combustion, solar energy generation, etc. However, considerable deviation of tube wall temperatures was found in the commercial EHEs, which will result in the overheating of tubes and affect the safe operation. In order to investigate the non-uniform heat transfer phenomenon, local heat transfer and hydrodynamics with...