கருணா ராஜா நடராஜன் - Academia.edu (original) (raw)
கருணா ராஜா நடராஜன்
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Chili is one of the most valuable as well as commercial crops of India. It is commonly drying und... more Chili is one of the most valuable as well as commercial crops of India. It is commonly drying under open sun; this practice is having lot of drawbacks which leads to poor quality. Solar tunnel dryer technology is an alternative to open sun drying. A large-scale natural convection solar greenhouse dryer was developed and tested at field levels. An experimental investigation was carried out in the dryer for drying 250 kg of red chilli in two intervals. The solar dryer reduced the moisture content of red chilli from 79% (w.b.) to about 10% (w.b.) in 55 h compared to 124 h taken by open-sun drying by saving 56% of drying time. The thermal efficiency of the dryer was found to be 16.25% for chilli drying with a specific energy consumption of 6.06 kWh/kg. The dried chilli produced in the solar greenhouse dryer showed high quality. It is found that solar tunnel drying process is a better alternate for open sun drying and also ensures the quality of product evidently.
A medium of storing thermal energy from Solar, Exhaust gases and waste heat from solar, exhaust g... more A medium of storing thermal energy from Solar, Exhaust gases and waste heat from solar, exhaust gas and waste heat from industries, is the usage of Low Temperature Energy Storage System (LTESS). In order to achieve the storage of energy, Phase Change Materials (PCM) is adopted. PCM is most preferred because of their high storage density, with lesser volume. A drawback of the system is that the thermal conductivity of PCM is very less and requires more time and surface area for loading and unloading of thermal conductivity. To overcome the problem, an attempt was made in the heat exchanger to incorporate Al micro particles in the paraffin PCM in order to increase its thermal conductivity. Both analytically and experimentally, the thermal conductivity of LTESS is determined. Maxwell-Garnett equation is used to determine the thermal conductivity of PCM and Transient Hot Wire Thermal Conductivity Measuring Apparatus KD2 probe is utilized to determine the thermal conductivity experimentally. There is significant change in values of both sensible heat and latent heat, by which, through the use of Al-PCM combination, the thermal conductivity has been seen to be increased to 1.904 W/mK, in contrast to the thermal conductivity of paraffin wax of 0.214 W/mK.
A CFD analysis has been performed on the multi-element airfoil. Stalls are experienced as a sudde... more A CFD analysis has been performed on the multi-element airfoil. Stalls are experienced as
a sudden reduction in lift and increase in drag, due to increase in angle of attack of the
aerofoil. In Aerodynamics increase in Angle of attack leads to increase in Lift up to certain
angle of attack, beyond that Stall occurs. Stall is the phenomenon where the Drag is increased
due to the flow separation and lift starts to Decrease. Beyond that the main drawback is the
Aerodynamic efficiency decreases during stall. In this paper, a 2-Dimensional CFD
investigation is performed on the stall phenomenon, associated with the flow field around the
multi-element Aerofoil at low Reynolds number. It provides the analysis of delay of stall,
hereby decreasing the takeoff time in aero-models. The stall angle has been reduced from 15-
17° to 13-15°, while analyzing
Chili is one of the most valuable as well as commercial crops of India. It is commonly drying und... more Chili is one of the most valuable as well as commercial crops of India. It is commonly drying under open sun; this practice is having lot of drawbacks which leads to poor quality. Solar tunnel dryer technology is an alternative to open sun drying. A large-scale natural convection solar greenhouse dryer was developed and tested at field levels. An experimental investigation was carried out in the dryer for drying 250 kg of red chilli in two intervals. The solar dryer reduced the moisture content of red chilli from 79% (w.b.) to about 10% (w.b.) in 55 h compared to 124 h taken by open-sun drying by saving 56% of drying time. The thermal efficiency of the dryer was found to be 16.25% for chilli drying with a specific energy consumption of 6.06 kWh/kg. The dried chilli produced in the solar greenhouse dryer showed high quality. It is found that solar tunnel drying process is a better alternate for open sun drying and also ensures the quality of product evidently.
A medium of storing thermal energy from Solar, Exhaust gases and waste heat from solar, exhaust g... more A medium of storing thermal energy from Solar, Exhaust gases and waste heat from solar, exhaust gas and waste heat from industries, is the usage of Low Temperature Energy Storage System (LTESS). In order to achieve the storage of energy, Phase Change Materials (PCM) is adopted. PCM is most preferred because of their high storage density, with lesser volume. A drawback of the system is that the thermal conductivity of PCM is very less and requires more time and surface area for loading and unloading of thermal conductivity. To overcome the problem, an attempt was made in the heat exchanger to incorporate Al micro particles in the paraffin PCM in order to increase its thermal conductivity. Both analytically and experimentally, the thermal conductivity of LTESS is determined. Maxwell-Garnett equation is used to determine the thermal conductivity of PCM and Transient Hot Wire Thermal Conductivity Measuring Apparatus KD2 probe is utilized to determine the thermal conductivity experimentally. There is significant change in values of both sensible heat and latent heat, by which, through the use of Al-PCM combination, the thermal conductivity has been seen to be increased to 1.904 W/mK, in contrast to the thermal conductivity of paraffin wax of 0.214 W/mK.
A CFD analysis has been performed on the multi-element airfoil. Stalls are experienced as a sudde... more A CFD analysis has been performed on the multi-element airfoil. Stalls are experienced as
a sudden reduction in lift and increase in drag, due to increase in angle of attack of the
aerofoil. In Aerodynamics increase in Angle of attack leads to increase in Lift up to certain
angle of attack, beyond that Stall occurs. Stall is the phenomenon where the Drag is increased
due to the flow separation and lift starts to Decrease. Beyond that the main drawback is the
Aerodynamic efficiency decreases during stall. In this paper, a 2-Dimensional CFD
investigation is performed on the stall phenomenon, associated with the flow field around the
multi-element Aerofoil at low Reynolds number. It provides the analysis of delay of stall,
hereby decreasing the takeoff time in aero-models. The stall angle has been reduced from 15-
17° to 13-15°, while analyzing