Showing papers by "Saroj Kumar Mohapatra published in 2012"

Brown hemp methyl ester: Transesterification process and evaluation of fuel properties

Abstract: The present study was conducted to standardize the esterification process parameters for the production of methyl ester of raw hemp oil. The effect of process parameters such as molar ratio, catalyst concentration, and reaction time was studied to standardize the esterification process and for estimating the highest recovery of ester with lowest possible viscosity. Based on the observations from the ester recovery and kinematic viscosity, it can be seen that raw hemp oil at 6:1 M ratio may be reacted with methanol at 60 °C reaction temperature for 45 min in the presence of 2 g of KOH and then allowed to settle for 24 h in order to get lowest kinematic viscosity with ester recovery of 90.62%. The yield of hemp methyl ester was found to be 90.62% with oil methanol ratio of 0.37 w/w and 0.01 w/w alkali catalyst. Different fuel properties such as density, kinematic viscosity, flash point, fire point, cloud point, pour point, free fatty acid content and calorific value of the hemp methyl ester and hemp oil were measured. From the properties and engine test results it has been established that methyl ester of hemp oil can be substituted for diesel oil. Methyl ester of above non-edible oil has several advantages among other new renewable and engine fuel alternatives along with its environmental benefits.

Effect of channel and plenum aspect ratios on the performance of microchannel heat sink under different flow arrangements

Abstract: Microchannels based heat sinks are considered as potential thermal management solution for electronic devices. The overall thermal performance of a microchannel heat sink depends on the flow characteristics within microchannels as well as within the inlet and outlet plenum and these flow phenomena are influenced by channel aspect ratio, plenum aspect ratio and flow arrangements at the inlet and outlet plenums. In the present research work an experimental investigation has been carried out to understand how the heat transfer and pressure drop attributes vary with different plenum aspect ratio and channel aspect ratio under different flow arrangements. For this purpose microchannel test pieces with two channel aspect ratios, 4.72 and 7.57 and three plenum aspect ratios, 2.5, 3.0 and 3.75 have been tested under three flow arrangements, namely U-, S- and P-types. Test runs were performed by maintaining three constant heat inputs, 125 W, 225 W and 375 W in the range 224.3 ≤ Re ≤ 1121.7. Reduction in channel width (increase in aspect ratio, defined as depth to width of channel) in the present case has shown about 126 to 165% increase in Nusselt number, whereas increase in plenum length (reduction in plenum aspect ratio defined as width to length of plenum) has resulted in 18 to 26% increase in Nusselt number.

Comparative Analysis of the Performance and Emissions Characteristics of a C.I. Engine Fuelled with Three Different Blends of Biodiesel Derived from Waste Mustard Oil

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Investigation of Flow of Centrifugal Slurry Pump Handling Bottom Ash

Abstract: Centrifugal pumps are used for transportation of solids and liquid over short to medium distance through the pipelines. A centrifugal pump designed to handle the liquids is normally single stage, end suction type having radial or mixed flow configuration of blades. Centrifugal pump of radial-flow type is mostly used in slurry service. A conventional centrifugal pump is designed to handle bottom fly ash mixture liquids. The modifications incorporated in the pump include enlargement of flow passages to accommodate bigger solid particles, robust impeller with smaller number of vanes, special seals and proper material of construction to ensure longer life. These have to be operated with relatively wide clearance at impeller-casing contacts to minimize choking and localized wear. These modifications increase the hydraulic losses in the pump and deteriorate the pump performance. The present study is concerned with the evaluation of the performance characteristics of a centrifugal slurry pump when handling bottom fly ash at 30% concentration of bottom fly ash slurry at different speeds1000, 1150, 1300 and 1450 rpm. From the experimental evolution it is concluded that the parameters defined for head and capacity of the conventional pumps are also applicable for the slurry pumps with water despite the constructional differences. From the bottom ash characteristics it is also observed that addition of the fly ash in the bottom ash developed head decreases with increases of the flow rate results decreases the power consumptions of the transportation of the bottom ash in pipelines.