POROUS MEDIUM MODEL OF A STORAGE TANK WITH AN IMMERSED HEAT EXCHANGER

摘要

A novel approach to model the transient fluid/thermal discharge of a solar storage tanks with an immersed heat exchanger is presented. The model treats the natural convection heat exchanger as a porous medium within the storage fluid Thus, it is capable of simulating practical heat exchangers comprising many tubes. In the present study, the model is applied to a rectangular storage tank with a 240-tube heat exchanger. Transient temperature distributions and flow streamlines demonstrate the complexity of the flow field and the extent of mixing during discharge. results show that the structure of the flow is affected by the presence of the tank walls and stratification is prevented. The computational resources required for these transient simulations are substantial and thus models have not been extended to more practical heat exchangers.