Department of Mechanical engineering
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Item Recalibrating Science & Technology Education for Environmental Sustainability- Re-Orientation of Text Books(IIETA, 2017-11) Bhattacharyya, SuvanjanSustainability aims at keeping the future of civilisation and society alive. Science and Technology is a tool for this. India has a long tradition of science, education and now a vastly expanded technical education system. New Textbooks or Learning Materials-print or digital, are absolutely essential for this to fulfil particularly. SDG, as listed Globally or Nationally. India’s ranking comes low in PISA, which is an International Students’ Evaluation for applying science education to real life problems, for school leaving students. Sustainability is linked to reality. In Global Institutional Ranking also India’s ranking is not high for the Universities. One of reason is improper learning materials, leading to unsustainability mindset. This paper attempts to find the reasons the shortcomings. From experience, observation and study, the author has attempted to point out solutions in one major area, i.e., paradigm shifts required for text books on Science and Technology, particularly at middle school level and Technical Institutions. One of the major conclusion is that, it is important to change orientations of Indian books with clarity and lucidity, the sustainability concepts. Writing books by Indian teachers mostly and involving learned professors in writing texts will enhance the technical knowledge base of the students, increase their employability by clearing fundamental concepts and thus take India forward to a sustainable future as a whole. This will also enable inclusive education and will also enhance the ‘Make in India’ conceptual framework.Item Numerical simulation of Laminar flow heat transfer Enhancement in a three-dimensional Channel flow with Inclined ribs(Cyber Times International Journal of Technology & Management, 2014-09) Bhattacharyya, SuvanjanEffects of ribs on forced convection heat transfer and friction loss behaviors for laminar airflow through a constant heat flux channel are numerically investigated in the present work. Ribs are known to enhance the heat transfer between the energy-carrying fluid and the heat transfer surfaces. A numerical investigation on the laminar flow and heat transfer behavior in the circular channel with inclined ribs for three different. The computations based on the finite volume method with the SIMPLE algorithm have been carried out with Reynolds number ranging from 100 to 1000. The numerical results show that the heat transfer of the inclined ribbed channel are improved about 90-110% compared with smooth duct because co-rotating vortices are generated on the cross section of channel. In addition, the effects of geometric parameters for ribs on the heat transfer, such as rib height, rib pitch, were analyzed. The heat transfer, pressure loss and thermal performance of the inclined ribs with different attack angles (θ) of 0o, 10o, 15o, 20o, 25o, and 90oare examined.Item 3d computational study of fluid flow and heat transfer in a dimple enhancer channel(Begell House, 2017) Bhattacharyya, SuvanjanHeat transfer behaviour in dimple enhancer channel swirl generator is investigated numerically. Vortex generator geometry is a widely used procedure for heat transfer improvement. This work presents the investigation of a dimple enhancer channel for turbulent heat transfer with air (Pr 0.707) as the working fluid. In the present paper, transition - SST model which can predict the change of flow regime from laminar through intermittent to turbulent has been used for numerical simulations. The simulation are performed using three dimple ratio (r = d/D = 0.1, 0.15 and 0.2) and three different space ratios (s = y/D = 2.0, 2.5, and 3.0). The computations were conducted with Reynolds number ranging from 100 to 50,000. The results indicate that the large dimple ratio and small space ratio yields a higher heat transfer value with relatively lower performance penalty. The transition from laminar to turbulent regime is observed between Reynolds numbers of 2000 to 3500 for all cases. For all investigated cases the performance factor (η) are almost greater than unity. This result is useful for the design of solar thermal heaters.Item Transport enehancement in a channel with mutiple triangular prisms(ASTFE, 2018-03) Bhattacharyya, SuvanjanThermohydraulic performances in a square channel fitted with triangular prism, using air (Pr = 0.707) as working fluid are investigated numerically. The triangular prism is placed in a square channel. Influences of triangular prism arrangement in forward direction are described. The Reynolds number varies from 100 − 50,000. Air has been used as a working fluid. In this paper, transition - SST model which can predict the transition of flow regime from laminar through intermittent to turbulent has been applied for numerical simulations. Due to the formation of vortices, the heat transfer is enhanced appreciably. The results indicate that in presence of triangular prism, heat transfer in a channel is augmented by around 10% - 12%. The increase in heat transfer is related to the vortex formation downstream of the triangular element. Heat transfer enhancement and friction loss increased with combined effect of three triangular prisms. Numerical results indicate that the use of triangular prisms the channel can prominently increase the heat transfer performance.Item Heat Transfer and Fluid Flow behaviours of a Square Twisted Micro-Channel(IIT Bombay, 2018-12) Bhattacharyya, SuvanjanThe heat transfer and pressure drop analysis of twisted square micro-channel is studied numerically for Reynolds number (Re) ranging from 10 to 250. The laminar flow model is used for formulation in Ansys fluent 15.0, since the flow is laminar. The governing equations are solved with a finite-volume-based numerical method. A three-dimensional non uniform grid was generated, in order to critically examine the flow and heat transfer. The effects of aspect ratio and twist ratio on the Nusselt number and friction factor are investigated. It is found that the twisted geometry of the channel evidently enhance heat transfer by generating longitudinal vortices, which strengthen flow mixing. Such small vortices also upsurge the turbulent kinetic energy (TKE) and decrease thickness of the boundary layer, which lowers local temperature nearby the target surface. Computational results show that the simulation with twisted micro-channel geometry considerably better than the case with straight micro-channel with respect to heat transfer performance.Item Thermohydraulic characteristics of transitional flow in a circular tube with inlet disturbances(HEFAT 2019, 2019-07) Bhattacharyya, SuvanjanThe influence of a triangular prism at the inlet of a circular tube on the thermohydraulic characteristics in the laminar, transitional and turbulent flow regimes is investigated experimentally. The effects on transition, i.e. the transition shift, due to the presence of triangular prism for three different clearance ratios (CR) are studied in this present work. The tube had an inner diameter of 20 mm, and length of 3.5 m (heated portion). Air was used as the working fluid. The test were conducted at two different heat fluxes of 2 and 4 kW/m2 for Reynolds numbers between 1 000 and 6 500, to ensure that all the three flow regimes were covered. The position of the triangular prism is at a distance (x) of 1.85 m from the inlet plane. The length of the pipe is 5.5 m, after 2 m from the inlet plane the pipe is heated with constant heat flux. The results show a good agreement with the available correlations. The effect on transition behavior due to the presence of triangular prism is reported in terms of Nusselt number, friction factor, j-factor and thermal performance factor (η). However, the heat transfer coefficient for this arrangement is showing more promising result as compared with the plain tube.Item Experimental Investigation of Performance And Emission Of CI Engine Using Additives-Fuel(ELK Asia Pacific Journals, 2016) Bhattacharyya, SuvanjanCI engines are very important and famous from the time of their invention; most of the automobiles are run by these engines. In this study, the effect of peanut oil blends with diesel is investigated experimentally and the performance and exhaust emission are recorded. Peanut oil and its 10%, 15%, 20%, 25% blends with diesel are investigated and compared with standard diesel. Experiments were conducted at constant speed of 1200 rpm, full load and at compression ratios of 12.5:1, 15:1, 17.5:1, 20:1 and 22.5:1. The effects of compression ratio on brake power, mechanical efficiency, indicated mean effective pressure and emission characteristics has been investigated and discussed. Comparative measures of CO2, NOx and CO have been presented and discussed. Exhaust gas temperature is very much low for all the blends compared to standard diesel. Increase in compression ratio improves fuel efficiency and power output. The novelty in this work is to permit 4-stroke CI engine manufacturer to change the compression ratio.Item Thermohydraulic Transport Characteristics of Micro Mixer in Micro Channel(Springer, 2016) Bhattacharyya, SuvanjanThis particular study consists of computational analysis based on transfer of heat and fluid flow characteristic of air with Pr = 0.7 through a 2-D micro-channel of an isothermal-fluxed wall of a circular shape micro mixer. In particular, a simulatory model has been established using computational fluid dynamics (CFD), i.e., Ansys Fluent 14.5 to investigate such effect. The formulations are done by the laminar flow model, since the flow is assumed to be laminar. The simulation is conducted for gaining an insight and understanding the physical behaviour of the thermal and fluid flow of air in the micro channel with built-in circular shape micro mixer under constant the conditions of isothermal wall. The configuration parameters include the, circular diameter (d) and pitch (p). Reynolds number varies from 10 to 800 in this particular study. A 2-D non-uniform grid was generated, in order to critically examine the flow and heat transfer. The effects of Reynolds number, Nusselt number, friction factor, temperature ratio of modified case to base case, are examined and discussed. All micro mixers at different pitch and diameter have good, tempature ratio of modified case to base case, which are greater than unity. It is highly possible to be implemented in the practical application like micro channel heat sink.Item 3D CFD Simulation of Heat Transfer and Friction Characteristics of Laminar Flow of Water through a Circular Duct with Centre-Cleared Twin Twisted Tape(IJATR, 2015-12) Bhattacharyya, SuvanjanHeat transfer behavior of laminar flow inside circular duct with centre-cleared twin twisted tape (CTTT) swirl generator was investigated numerically. The governing equations were solved with a finite-volume-based numerical method. A three-dimensional non uniform grid was generated, in order to critically examine the flow and heat transfer. The centre-cleared twin twisted tapes were tested in the current work; investigations were performed in the Reynolds number range of 100- 1,000 with four different CTTTs at twist ratio (TR) of H/W = 1.0, 2.0, 3.0 and 4.0. Water is used as working fluid (Pr = 7). The effects of Reynolds number, Nusselt number, friction factor, convective heat transfer coefficient were examined and discussed. The use of CTTT was found to increase the heat transfer considerably when compared with plain tube. The Nusselt number increased with the increase of Reynolds number. The overall enhancement ratio has been calculated in order to discuss the overall effect of CTTT and the working parameters. The present findings would be useful inputs for the design of solar thermal heaters and heat exchangers.Item Numerical Investigation of Heat Transfer under Impinging Annular Jets(GRDS Publishing, 2016) Bhattacharyya, SuvanjanIn the present work, numerical investigations have been done to predict the transport phenomena and heat transfer characteristics of laminar annular jets impinging on a surface. For analysis purpose, the characteristics of an annular jet has been compared with that of a circular jet at the same Reynolds number with same amount of mass and momentum efflux at the nozzle exit. The Reynolds number of the jet is defined on the basis of width of the annular part. The distribution pattern of the Nusselt number over the impinging surface scales with Re0.54.