Parametric study of charging inlet diffuser performance in stratified chilled water storage tanks with radial diffusers: Part 1 - Model development and validation

A computational fluid dynamics (CFD) model has been developed to simulate t he flow and heat transfer near a lower radial inlet diffuser in a cylindric al stratified chilled water storage tank during charging. The model was use d to perform parametric simulations of inlet diffuser performance in full-s cale tanks during thermocline formation, from which first-order correlation relating thermal performance to tank and diffuser design parameters were d erived. Part 1 describes the development of the CFD model and its validatio n. Part 2 reports the results of the parametric study. The two-dimensional, transient model was implemented in a commercial finite element code. The m odel has been validated with field-measured data from two full-scale tanks. Laminar analysis predicted field-measured temperature profiles well, even under ostensibly transitional conditions, provided that variations in inlet temperature during the field tests were accurately modeled. These results suggest that turbulence has a secondary effect on the development of thermo clines within the range of parameters considered and that laminar models ma y be useful for modeling performance of full-scale tanks over a wide range of inlet parameters. The fully developed temperature profile was found to b e insensitive to the velocity distribution assumed at the inlet.