Compactness factors for rolled, stacked-screen regenerators

The objective for the research was to determine how the heat transfer and pressure drop characteristics changed in a stacked, wire-screen regenerator, if the screens which were used to construct the matrix were rolled to decrease their thickness, thereby reducing the volume of the regenerator. Reducing the "dead volume" for regenerative refrigeration cycles was the ultimate motivation for this research. The results show the compactness factor (j/sub H//f) is adversely affected by rolling. Flattening the screens by 15, 30, or 50%, does not cause a new mechanism for heat transfer to be introduced to the matrix, but it does increase the total pressure drop. Rolling the screens causes a decrease in both wetted surface area and pore size, hence, surface phenomena like heat transfer are reduced, but, the inertial pressure drop increases. The effectiveness of the regenerator is also reduced by rolling the screens.