An analytical method for determining transient temperature field in a parallel-flow three-fluid heat exchanger

In this paper we solve analytically, by the method of Laplace transforms, the set of partial differential equations describing the transient temperature field in a parallel-flow three-fluid heat exchanger. The analytical solution is obtained for a special case of the heat exchanger with two heat connections between the fluids, constant temperature in one channel, and step increase of the inlet temperature of one fluid. The analysis is illustrated by exemplary calculations.