IDEA #5K8VJB Heat Exchange Surfaces With Improved Thermal-Hydraulic Characteristics For Microturbine And Other Applications

HEAT EXCHANGE SURFACES WITH IMPROVED THERMAL-HYDRAULIC CHARACTERISTICS FOR MICROTURBINE AND OTHER APPLICATIONS Description The novel heat exchange surfaces have been developed based on application of the surface vortex structures providing the high rate of heat transfer aug(cid:173) mentation (Nu / Nu0 = 4...5) and high thermal hydraulic per(cid:173) formance (Nu / Nu0 / f / f0 = 0.5...2.0). These surfaces are manufactured from stainless steel sheets ( =0.2 mm), on which dimples are stamped in the staggered or in-line mode. Overall around 30 types of narrow rectangular channels (Fig.l), using dimples or dimples-pimples on both walls have been tested to obtain the average heat transfer and total pres(cid:173) sure losses. The down-scale prototype of counter-flow spiral heat exchanger (Fig.2) using the diagonal ribs and surface dimples has been developed and tested in the Ukraine. The heat transfer effectiveness is up to 90%, the overall pressure losses are lower of 5%. The pressure difference in adjacent channels of heat exchanger (hot gas and cold air) is up to 5 Bar. Innovative Aspects and Main Advantages The dimpled surfaces will operate at greater Reynolds num(cid:173) bers enabling to reach the higher heat transfer rate. As a result, the heat exchange surface can be reduced to 20% com(cid:173) pared with traditional augmenters (cross-corrugated sur(cid:173) faces). Areas of application The novel heat exchange surfaces can be employed in: • Heat waste recuperators for micro-turbine applications; • Heat exchangers utilizing the waste heat beyond internal combustion engines (diesels consuming the natural gas) and other industrial equipments; • Recuperators for gas turbine engines (helicopter applica(cid:173) tions); • Heat exchangers for the housing sector. Pic. 1 Heat exchanger surfaces Pic.2 Heat exchanger core Stage of development Laboratory tested. A wide database regarding the heat trans(cid:173) fer, pressure losses and thermal-hydraulic performance has been obtained for over 30 types of narrow dimpled channels. The down-scale prototype of a spiral counter-flow heat exchanger for micro-turbine applications has been developed and tested in Ukraine. Patented in the Ukraine. Contact details Borisov lgor,PhD Institute of Engineering Thermophysics, NAS of Ukraine 03057, Kyiv, 2a Zhelyabov str. Phone: +38 (044) 453-28-53 Fax: +38 (044) 456-60-91 E-mail: borisov@vortex.org.ua