Showing papers by "Shireesh B. Kedare published in 2012"

Review on Savonius Rotor for Harnessing Wind Energy

Abstract: Wind machines convert kinetic energy of the wind into usable form of mechanical energy or electrical energy. The Savonius rotor is a vertical axis wind machine which is simple in design. High starting torque characteristics make it suitable for standalone power generation as well as water pumping applications. This paper reviews the literature on the performance characteristics of the Savonius rotor. Multi-bladed rotor, multistage rotor, shape of the blade, use of deflecting plate, guide vanes and nozzle augmentation are several ways to enhance the performance characteristics. This review would help an engineer in building an improved Savonius rotor for a given application.

Motoring test of a stirling cycle engine system while acting as a cooler

Abstract: A lot of work is done on the Stirling coolers of various configurations at IIT Bombay. This includes the development of nitrogen liquefier, with a capacity of 5–6 liter/h, as a higher capacity cooler to miniature coolers, with capacities as low as 1 W at 80 K, for IR detector cooling onboard satellite. Presently work on "Development of Stirling Engine for 1.5 kW electrical power output" is in progress with the intention of making use of the experience gained in the process. It is of Beta type with rhombic drive mechanism. This paper presents the results of a cooling system which has not been designed as a cooler but has been designed for providing power in the form of an engine. It also discusses the experience during motoring test and initial trials on Beta type Stirling engine with Rhombic drive mechanism as cooler. Initially, the Stirling cycle engine setup is tested by welding single tube to the cylinder head and charging at slightly higher pressure than ambient. Further, four tubes are welded to the cylinder head to provide the sufficient flow passage through heat receiving tubes, which was not case with single tube. The condensation at the top of cylinder head and around the tubes is observed in three minutes after starting, with Helium as working fluid and charging pressures of 3.1, 4 and 5 bar. The pressure ratio, which is ratio of the maximum pressure to the minimum pressure in the cycle system, is around 1.72. The system is operated without any substantial load and let some of the dimensional mismatch reduce by way of wearing out unmatched components. Then it is operated repeatedly, in this fashion so that every time the system is restarted, it should need less power. After testing and conducting trials cylinder head is inspected visually. No scratches or rubbing impressions are observed at contact the contact surfaces.

Comparison of Cavity Receivers with and without Mouth-Blockage of Different Shapes and Sizes Used in Paraboloid Dish Applications

Abstract: Numerical three-dimensional studies of the natural convection and radiative heat loss from cavity receiver of different shapes with and without mouth-blockage have been investigated under isothermal wall condition Convective heat loss is found to decrease for cavities having mouth blockage created by reducing aperture area (case I) whereas it enhances when mouth blockages are introduced by increasing the cavity dimensions and keeping the same aperture area (case II) Convective loss is characterized by using the convective zone area (Acb ) Conical cavity yields the lowest convective loss whereas hetro-conical cavity gives the highest convective loss among different shapes investigated Radiative loss is independent of cavity inclination and is found to be nearly constant for all cavity shapes and cavity configurations (with or without mouth blockage) so long as the aperture area remains the same; it is proportional to the aperture area However, investigations on decrease in heat loss of mouth-blocked cavities needed to be coupled with the estimation of concentrated flux