Single phase flow characteristics in the headers and connecting tube of parallel tube platen systems

Analytical solutions have been obtained for single phase flow in parallel tube platen systems where the platen configuration (geometric shape and dimensions) of each connecting tube within a platen can vary. Continuous and discrete mathematical models have been derived to study the distributing and combining flow characteristics in platens along header axes and in connecting tubes within each individual platen, respectively. The specific volume of working fluid is assumed to vary linearly along the connecting tube length, in order to close the mathematical equations. Analytical solutions of static pressure and velocity in the headers and connecting tubes have been obtained firstly under the assumption that the friction along the headers can be neglected. Then, these solutions are corrected to account for the effects of friction along the headers. Both sets of solutions are the general solutions for all flow configurations of parallel tube platen systems where the flow parameters in the headers are one-dimensional and those in connecting tubes are three-dimensional. These general solutions can be applied directly to the design and analyses of superheaters and reheaters in power boilers, and other heat exchangers of same configurations.