Ceramic Cross Flow Recuperator Design Parameters

GTE Products Corporation has developed a compact ceramic cross flow recuperator for high temperature industrial heat recovery applications. They recently completed a jointly funded project with the DOE, (Contract #EX-76-C-0 1-2162) to demonstrate the performance of the ceramic recuperator in various industrial furnaces. The ceramic cross flow recuperator core has multiple rectangular flow passages (perpendicular to each other) for the air and gas. Various flow passages are available contingent upon requirements of the particular application. In selecting and sizing a matrix for a given application, one may design a recuperator on the basis of a minimum for one or more of the following parameters; frontal area, length, volume, weight, pressure drop and cost. This paper discusses how the designer can select an optimum design from the various heat exchanger surfaces available and then predict the performance of a recuperator in any given application. The results of wind tunnel tests utilizing a single blow technique, determining a heat transfer parameter, the Colburn factor (j), and a flow friction parameter, Fanning Friction factor (f) are presented and discussed. Methods that illustrate how the (j) and (f) data can be used to compare the relative merits of two or more heat exchanger surface are presented. A typical furnace recuperation example is presented and calculations are detailed to illustrate the design procedures