Heat Transfer Enhancement of Swiss-Roll Recuperator

For the advanced micro-power systems based on the use of microturbines, one of the major goals is to achieve a higher efficiency system, besides compact size and high power density, for the purpose of energy-saving. An exhaust heat recovery recuperated system then becomes mandatory for higher efficiency. The paramount requirements for recuperator are high effectiveness and low pressure loss across the recuperator. The research is aimed at the heat transfer enhancement for the innovative, patented Swiss-roll recuperator. The Swiss-roll recuperator is basically the primary-surface type. It is composed of two flat plates that are wrapped around each other, creating two concentric channels of highly rectangular cross-section. Theoretically, it has the advantages of high effectiveness and low pressure loss. The effectiveness of this recuperator can be increased by increasing the number of turns, which adds a great amount of volume. For maintaining compact size and high effectiveness, a Swiss-roll recuperator with chessboard type flow channels with cross-wavy or cross-corrugated structures is proposed to enhance the heat transfer rate by increasing the contact area between cold and hot flows. It will increase the effectiveness of Swiss-roll recuperator tremendously. The studies include the thermal design and analysis of the Swiss-roll recuperator. A three-dimensional numerical model is constructed to investigate the effects of the number and size of the channels on the effectiveness and pressure loss. The roles of the mass flow rates, the specific heat of the flow, and the number of transfer unit are also analyzed with the model. In addition, thermal testing is performed to validate the thermal designs and the thermal characteristics of the recuperator, by comparing the experimental and computational results. The enhancement technology for the Swiss-roll recuperator is the key to the improvement of the recuperators and the microturbines.

Project ID:PB10007-7230
External Project ID:NSC100-2221-E182-053-MY2