Gopal Krishan

Dr. Gopal Krishan


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 February 2022 in Arabian Journal for Science and Engineering
Verified
Journal Article
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TJTanuj Joshi
Tanuj Joshi
OPOm Parkash
Om Parkash
Gopal KrishanGopal Krishan
Gopal Krishan
Slurry flow (water–glass beads) through a horizontal pipe of diameter, 0.0549 m and length, 3.8 m with two particle sizes, i.e., 125- and 440-micron, has been numerically modeled and investigated based on the kinetic theory of slurry transportation. The effect of particles interaction on the pipe flow characteristics such as velocity profile, wall shear stress, vector regime, granular pressure and temperature has been evaluated at different solid concentration and flow velocity range. It is well established that the pressure drop is the key parameter for the design of efficient slurry pipeline system, which is influenced by factors such as flow velocity, slurry viscosity, solid concentration, pipe material and pipe geometry. However, to best of our knowledge, the estimation of pressure drop at different pipe roughness height and a concentration range of 40–60% is not yet established. Therefore, in the present work, the numerical simulation is carried out for slurry flow through a horizontal pipeline at different roughness heights (Rh = 10–50 micron) and Prandtl numbers, i.e., 1.34, 2.14, 3.42 and 5.83. The kinetic parameters are calculated at a flow velocity (Vm) of 1–5 ms−1 and solid concentration (Cw) range of 40–60%. The results and procedure of the current simulation are validated against the available experimental results in the literature. The outcomes of the present work reveals that pressure drop increases with increase in pipe roughness height for the chosen velocity and solid concentration range. In addition, the larger particle is found to have more influence on the pressure, velocity, temperature distribution for the entire range of flow velocity and solid concentration. Furthermore, settling velocity and specific energy consumption are also predicted and discussed through the slurry pipeline. The findings show that the settling velocity of particle increases with increase in particle size at different Prandtl number. The energy efficiency for solid transportation through pipeline at different Prandtl numbers and particle size are also evaluated. Based on the results, it is concluded that specific energy efficiency varies with solid concentration and particle size, i.e., higher concentration and larger particle size demonstrates higher energy consumption. Furthermore, fluid at low Prandtl number exhibits higher energy consumptions. In order to design the efficient slurry pipeline system, it is recommended that the slurry must be transported at low velocity and high Prandtl number.

1 May 2023 in Physics of Fluids
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Journal Article
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TJTANUJ JOSHI
TANUJ JOSHI
OPOM PARKASH
OM PARKASH
Gopal KrishanGopal Krishan
Gopal Krishan
The energy expense of slurry transportation through the pipeline plays a vital role in the economics of various modern industries, such as mining, crude oil, petroleum, and mineral processing. Therefore, it is essential to develop a suitable condition by which we can efficiently transport slurry without affecting the environment and capital costs. To solve these problems, a steady state three-dimensional multiphase Eulerian RNG k–ε turbulence model based on the kinetic theory of granular flow is developed to investigate transportation parameters like pressure distribution, concentration distribution, head loss, settling velocity, and specific energy consumption. Four different particles named bottom ash, glass beads, iron ore, and silica sand with five different sizes, 125, 200, 275, 350, and 440 μm are transported through 3.8 m long straight pipe having 54 mm pipe diameter. The trends of various transportation properties with varying flow velocity (Vm = 1–5 m/s) and efflux concentration (Cw = 40%–60%) are presented. The numerically obtained results for different slurries and water are in good agreement with the past experimental data available in the literature. The computational finding shows that the transportation of bottom ash requires minimum energy, whereas silica sand needs the maximum. In addition, the degree of deviation into transportation properties increases with the particle size, efflux concentration, and flow velocity.

1 January 2022 in ASME Open Journal of Engineering
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Journal Article
Open access
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TJTANUJ JOSHI
TANUJ JOSHI
RSRavikant Sharma
Ravikant Sharma
VMVinod Kumar Mittal
Vinod Kumar Mittal
VGVikas Gupta
Vikas Gupta
Gopal KrishanGopal Krishan
Gopal Krishan
In the present paper, a three-dimensional finite element model of the Charnley implant has been developed to analyze the stress–strain distribution and deformation over the stem prosthesis. Patient-specific dynamic forces have been considered for the analytical evaluation using commercial finite element code. The impact of each dynamic activity has been analyzed separately using six different biocompatible alloy materials made of titanium and cobalt-chromium. Mechanical parameters have been evaluated to envisage the longevity and functionality of the implant. The performance of different materials for each suitable gait pattern is analyzed using finite element code. Consequently, Cobalt chromium alloys (CoCrMo alloy) demonstrate better results, i.e., maximum stress, minimum deformation, and strain as compared with other materials. Every dynamic motion, viz., walking, standing up, sitting down, going upstairs, and going downstairs are found in good agreement with the safety factor for every biomaterial. Additionally, going downstairs and sitting down gait motion exhibits the maximum and minimum stress–strain level, respectively. Based on the outcome of the presurgical study, it is recommended that CoCrMo alloys should be preferred over other materials.

1 February 2024 in Physics of Fluids
Verified
Journal Article
Open access
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TJTANUJ JOSHI
TANUJ JOSHI
OPOM PARKASH
OM PARKASH
Ralph Kristoffer B GallegosRalph Kristoffer B Gallegos
Ralph Kristoffer B Gallegos
Gopal KrishanGopal Krishan
Gopal Krishan
In this study, a sophisticated three-dimensional computational model was developed to investigate the kinetic and thermal characteristics of a bi-model slurry. This model utilized the Eulerian–Eulerian Re-Normalization Group k–ε turbulence approach in conjunction with the kinetic theory of granular flow. The slurry, composed of different combinations of silica sand and fly ash, was transported through a straight pipeline under varying Prandtl numbers. Five different mixture combinations were considered, ranging from 65% silica sand and 35% fly ash to 100% silica sand. The slurry was transported using four different Prandtl fluids with varying temperatures. The pipe wall was maintained at a constant temperature of 400 K. The computational results yielded significant findings. A mixture with a higher proportion of fly ash (65:35) exhibited superior flow characteristics when combined with a low-viscosity Prandtl fluid (Pr = 2.88), resulting in a minimal pressure gradient and specific energy consumption. Enhanced energy efficiency was observed at lower Reynolds numbers and reduced efflux concentrations. Additionally, the 95:05 mixture demonstrated the highest heat transfer coefficient, with further improvements as flow Reynolds numbers and efflux concentrations increased. These results provide valuable insight into optimizing the transportation of bi-model slurries for various industrial applications, emphasizing the importance of composition and Prandtl numbers.

28 January 2023 in European Journal of Mechanics - B/Fluids
Verified
Journal Article
Closed access
Gopal KrishanGopal Krishan
Gopal Krishan
NONay Lin Oo
Nay Lin Oo
RSRajnish N Sharma
Rajnish N Sharma

15 September 2024 in Mathematics
Verified
Journal Article
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TJTANUJ JOSHI
TANUJ JOSHI
AGAbhinav Gupta
Abhinav Gupta
OPOM PARKASH
OM PARKASH
Ralph Kristoffer B GallegosRalph Kristoffer B Gallegos
Ralph Kristoffer B Gallegos
Nay Lin OoNay Lin Oo
Nay Lin Oo
Gopal KrishanGopal Krishan
Gopal Krishan
The study establishes two mathematical formulations to predict the pressure drop in a solid–liquid slurry flowing through a straight pipe. Employing the Eulerian–Eulerian RNG k-ε model, the computational investigation uses water as the carrier fluid and glass beads as solid particles. The analysis spans various particle sizes (d50 = 75–175 μm), volumetric concentrations (Cvf = 10–50%), and velocities (Vm = 1–5 m/s). The first model, developed using the MATLAB curve-fitting tool, is complemented by a second empirical equation derived through non-polynomial mathematical formulation. Results from both models are validated against existing experimental and computational data, demonstrating accurate predictions for d50 = 75–175 µm particles within a Reynolds number range of 20,000 ≤ Re ≤ 320,000.