Experimental study for shell-and-tube molten salt heat exchangers

Abstract

Molten salt heat exchangers are key components in some advanced power systems. Two shell-and-tube molten salt heat exchangers are experimentally investigated, including a gas cooled one with finned tubes and a molten salt to salt one with segmental baffles in the shell side. Based on a nonlinear regression scheme, heat transfer coefficients in both the tube and shell sides are obtained. Heat transfer characteristics of molten salt in the tube side are discussed and compared with three empirical correlations. It is found that Wu’s Equation has better agreement with the experimental data than Gnielinski’s and Hausen’s Equations in transitional flow region. For the developing laminar flow in the tube side, the widely used Sieder–Tate correlation underestimates heat transfer coefficients of molten salt by up to 30%. Compared with oil and a chart method proposed from sufficient database, molten salt seems to have better heat transfer performance than other working fluids in the baffled shell side. Further researches on the heat transfer characteristics of molten salt in the shell side with baffles are needed and significant.