Faculty Publications
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Item The use of Dimensional Analysis and Optimization of Pneumatic Drilling Operations and Operating Parameters(Springer India sanjiv.goswami@springer.co.in, 2012) Kivade, S.B.; Murthy, C.S.N.; Vardhan, H.Dimensional analysis was used to demonstrate the significance of these important parameters, grouped together in dimensionless numbers which will then allow for optimum use of limited laboratory data to produce better results. It allows for reduction of total effort in designing laboratory experiments, reducing total load and cost, permitting variation of the important dimensional groups rather than individual drilling operating parameters, hence a more efficient design of experiments can be realized. Drilling operations are very expensive endeavors and efforts are continuous by engineers and researchers to achieve the optimum penetration rate. To enhance bit life and penetration rate, optimization of bit design and drilling operations must be realized. To measure the penetration rate of the pneumatic drill, a fabricated pneumatic drill set up available was used. Laboratory tests were carried out to obtain the physical and mechanical properties of the rock samples. Penetration rate has been derived by means of regression statistics method. In order to overcome this drawback, dimensional analysis was used to derive relevant dimensional groups leading to the development of empirical equation of penetration rate. © 2012, The Institution of Engineers (India).Item Laboratory Investigations on Percussive Drilling(Springer India sanjiv.goswami@springer.co.in, 2013) Kivade, S.B.; Murthy, C.S.N.; Vardhan, H.The laboratory investigation was carried out on ten rock samples using pneumatic drill with drill bits of different diameters. In general, the process of drilling always produces sound. Sound is generated from the bit-rock interface regardless of the material of the bit used in drilling. The predicted sound level and penetration rate are a product of the drill power and the physical properties of the rocks penetrated. Rock samples were collected from the field and physical properties of the rocks were determined in the laboratory. The sound level and penetration rates were correlated with the rock properties. The compressive strength and abrasivity exhibit strong correlations with the sound level and penetration rate. It was concluded that, among the rock properties included in this study, the compressive strength and abrasivity values are the dominant ones affecting the penetration rate and sound level of percussive drills. Though ten rock samples have been covered in this study, detailed analysis of only one of them is presented. © 2013, The Institution of Engineers (India).Item Investigation of Noise Level and Penetration Rate of Pneumatic Drill vis-à-vis Rock Compressive Strength and Abrasivity(Springer India sanjiv.goswami@springer.co.in, 2014) Kivade, S.B.; Murthy, Ch.S.N.; Vardhan, H.In this paper, detailed studies were carried out to determine the influence of rock properties on the sound level produced during pneumatic drilling. Further, investigation was also carried out on the effect of thrust, air pressure and compressive strength on penetration rate and the sound level produced. For this purpose, a fabricated pneumatic drill set up available in the institute was used. Rock properties, like compressive strength and abrasivity, of various samples collected from the field were determined in the laboratory. Drilling experiments were carried out on ten different rock samples for varying thrust and air pressure values and the corresponding A-weighted equivalent continuous sound levels were measured. It was observed that, very low thrust results in low penetration rate. Even very high thrust does not produce high penetration rate at higher operating air pressures. With increase in thrust beyond the optimum level, the penetration rate starts decreasing and causes the drill bit to ‘stall’. Results of the study show that penetration rate and sound level increases with increase in the thrust level. After reaching the maximum, they start decreasing despite the increase of thrust. The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength and abrasivity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of predictor variables. © 2014, The Institution of Engineers (India).