Bücher von Tarun Goyal

In this investigation, an effective approach based on multi-variable linear regression and X-ray method has been developed to determine the optimum conditions leading to minimum porosity in AlSi9Cu3 aluminum alloy die castings. The experimental results using Taguchi L27 orthogonal array were used to map the relationship between process parameters and porosity formation of the die cast part and to study the break load behavior of various level of porosity formation in High Pressure Die Casting (HPDC) process. In this investigation, TBC automatic machine of 500 capacity, Zwick break load of 250 kN capacity machine, Bosello high technology industrial X-ray machine have been used and comparison of previous process parameters and after optimization of process parameters have been studied and their results also studied. Lowest Porosity noted after process parameter optimization i.e. level 1, at furnace temperature 690 ¿C, Die temperature 190 ¿C, plunger velocity at first stage 0.18 m/s, plunger velocity at second stage 2.6 m/s and third stage pressure 280 bar. Break load improved from 8.43 kN to 19.83 kN and 14.0 kN to 26.0 kN.

This work was an experimental study on EDM during machining of Die Steel H-11 by hexagonal electrode. The work was analyzed by using Taguchi¿s method. Material Removal Rate (MRR) and Surface Roughness (SR) were the response variables. Flushing pressure, Current, Pulse ON time and Pulse OFF time are the four input parameters taken during this study. Results of response table obtained from Taguchi¿s method shows that the Current and Pulse ON time are the most dominating factors which effects MRR and SR the most as compared to other input parameters. In the optimization of MRR, it has been observed that the higher value of MRR is obtained by increasing the Pulse ON (2 µs to 5 µs) within the selected range of input parameters. It has been also observed that by increasing the Pulse ON from 2 µs to 5 µs, the MRR is increased by .027 to .052 (92%). In the optimization of SR, it has been observed that the lower value of SR is obtained by decreasing the Current (12 A to 4 A) within the selected range of input parameters. It has been also observed that by decreasing the Current from 12 A to 4 A, the SR is decreased by 3.56 to 2.07 (71%).

Both the heat transfer coefficient and friction factor are found to be strong functions of bed parameters. The effective efficiency is a useful parameter to take into account the effect of enhanced useful heat gain and friction losses. By maximizing the effective efficiency, the bed parameters can be optimized with regards to high useful heat gain and low friction losses. In the present work, solar air heaters packed with wire mesh matrix have been optimized for maximum effective efficiency with respect to bed parameters i.e. number of layers, bed porosity and pitch to diameter ratio of wire mesh. A computer program had been developed for simulation for optimal design of packed bed solar air heaters. The results of optimization are presented in the form of design plots for packed bed solar air heaters in terms of bed parameters. These plots can be used for selecting the optimal bed parameters and predicting the thermal efficiency of these solar air heaters for a given temperature rise and insolation.

The cost of fuel direct and indirect, environmental aspects and the degrading of dryer material as a result of possible reactions with heating media are some discouraging parameters operative in conventional drying. The present work is targeted to effectively using solar drying technologies. Conventional solar air heaters used for heating air in general, exhibited low thermal efficiency, attributed to poor heat transfer rate from absorber plate to air flowing in a duct on the lower side of the absorber plate. Packing elements have been employed to pack the duct of solar air heaters with a view to enhance the thermal efficiency. However, in such systems the pumping power needed to overcome the friction losses could reduce the benefits of increased useful heat gain. Thus the design of packed bed solar air heaters with high heat transfer rates and low friction losses draws renewed interest.