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Author: search.filters.author.Bhattacharyya, SuvanjanStart date: 2010

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    Solar drying systems for domestic/industrial purposes: A state-of-the-art review on topical progress and feasibility assessments.
    (Elsevier, 2024-01) Bhattacharyya, Suvanjan
    In this era of commercialization, energy scarcity and food security are two of the major global challenges owing to the continuously growing population. The significant post-harvest food loss witnessing alarming hunger statistics have motivated the contributors and several decision-makers to put their serious efforts towards promoting food security globally. Solar drying is identified as a widely accepted, qualitative, and sustainable food preservation scheme. This article aims to review various strategic advancements of different solar energy-based drying systems comprehensively; those are being utilized globally for domestic and commercial purposes.The article explores various parameters affecting the solar dryer performance and details different methods used for performance improvement. In addition to the comprehensive discussions on the pre-eminent qualitative impacts of solar dryers, this article takes an opportunity to highlight their socio-economic and environmental aspects, provides comparative assessment through case studies and discusses the current challenges associated with solar dryer. The solar irradiation intensity, air-flow, dryer geometry, and mode of operations are recognized as crucial parameters affecting the performance of solar dryers.Amongst various categories of solar drying methods, the forced convection-assisted mixed-mode dryers are observed as most efficient ones.Application of latent heat energy storage materials is suggested as suitably efficient performance enhancement techniques for different solar drying systems, enabling their applications in remote areas with extended operational periods during nights or cloudy seasons also. The favourable qualitative, environmental, and social aspects of several solar drying strategies confirm their viability to different domestic as well as industrial applications. However, higher initial costs, and hence; extended payback periods may limit their adoptions by smallholder farmers. However, the multiple-season applications of these equipment may result in improved payback scenarios by more than 50%.
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    Enhancing heat transfer in heat exchanger tube using four-shape cutting cone (FSCC) inserts: a numerical analysis
    (Taylor & Francis, 2024-08) Bhattacharyya, Suvanjan
    The study introduces a new design modification for regular smooth tubes, incorporating the four-shape cutting cone (FSCC) to enhance heat transfer without increasing friction charge. Numerical simulations are used for processes heat and flow characteristics in the turbulent flow regime using certain parameters, ranging from 4000 ≤ Re ≤32,000. FSCC inserts can improve heat transmission, which lowers energy consumption in heat exchanger tube and helps achieve sustainability goals. A FSCC vortex was placed inside a smooth tube that measured 1500 mm in length, 30 mm in inner diameter (Din), and 35 mm in outer diameter (Do) for testing purposes. The FSCC measured (Dtop) = 20 mm at the top and Dbase = 28 mm at the base, with a thin 0.8 mm thickness (t). In this study, the Nusselt number (Nu), friction factor (fr), and thermal performance evaluation criteria (TPEC) are examined in relation to FSCC perforations (N = 0, 2, and 3) and pitch-to-hydraulic ratios (PR = P/Din = 2.5, 3.5, 4.5, and 5.5). The effects of perforations, i.e. hole number N = 0, 2, 3 and P/Din = 2.5, 3.5, 4.5, and 5.5, are considered for the analysis. The integrated tube has higher TPEC and average Nusselt numbers as compared to the smooth tube. Additionally, it uses perforations and to look at fluctuations in the average entropy generation rate (Savg). The study found that FSCC-inserted tubes have a 9.3 and 17.9 times higher Savgf than smooth tube at Re = 32,000 and 4000, respectively, for N = 0 FSCC heat exchanger tube, but at Re = 32,000, the Savgh of FSCC is 0.4 times lower. Smooth tube improves average entropy generation (Savg), while friction flow creates irreversibility defects. Smooth tube performance in Savg is inferior, with Savgh declining with Re and N. According to the study, vortex/swirl flow, boundary layer disturbance, and fluid mixing are the main factors influencing fluid flow, which is improved by the FSCC integrated tube and improves heat exchanger performance. Nusselt number and the friction factor both decrease as perforations increase while TPEC also increases. The results suggest that the FSCC is a useful tool for improving the efficiency of tube heat exchangers. The maximum TPEC is observed around 2.44 for N = 0 at Re = 4000 and P/Din = 3.5.
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    Numerical study on thermal–hydraulic characteristics in a inclined mini-channel for solar PV panel cooling with external magnetic field and magnetic nanofluid
    (Elsevier, 2024-01) Bhattacharyya, Suvanjan
    A pronounced demand for compact heat exchangers exists within the electronics and HVAC sectors. The current computational research meticulously analyzes how the implementation of magnetic nanofluid and the application of an external magnetic field impact the thermal performance of a compact inclined heat exchanger. A magnetic nanofluid comprising a 2 % volume fraction of TiO2 nanoparticles dissolved in pure water is utilized. The investigation involved altering the channel angle from 0° to 90° and encompassed Reynolds numbers ranging from 150 to 190, coupled with variations in magnetic intensities from 0 G to 2000 G. At 0 degrees angular position, the Nusselt number experiences incremental enhancements of 33.04 %, 28.65 %, and 24.75 % across Reynolds numbers of 150, 170, and 190, respectively, when transitioning from 0G to 2000G. Similarly, at a 45-degree angular position, there are improvements of 18.50 %, 16.41 %, and 14.44 % for Reynolds numbers of 150, 170, and 190, respectively, under the same 0G to 2000G transition. Moreover, at a 90-degree angular position, improvements of 16.13 %, 14.30 %, and 12.60 % are observed for Reynolds numbers of 150, 170, and 190, respectively, within the 0G to 2000G transition. Additionally, at 0 degrees angular position, skin friction experiences incremental enhancements of 117.55 %, 95.77 %, and 79.65 % across Reynolds numbers of 150, 170, and 190, respectively, upon transitioning from 0G to 2000G. Similarly, at a 45-degree angular position, skin friction demonstrates improvements of 60.39 %, 52.79 %, and 47.44 % for Reynolds numbers of 150, 170, and 190, respectively, under the same 0G to 2000G transition. Furthermore, at a 90-degree angular position, skin friction showcases improvements of 50.26 %, 45.06 %, and 41.47 % for Reynolds numbers of 150, 170, and 190, respectively, within the 0G to 2000G transition. The thermal performance factor decreased with an augmented angle of inclination, while it increased with escalating intensities of the external magnetic field. Furthermore, the study revealed that the temperature performance coefficient surpassed unity for lower inclinations when a magnetic field intensity of 1500G was applied. This coefficient remained above unity across all angles when a magnetic field of 2000G was utilized.
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    Drying science and technology
    (Intechopen Publisher, 2024) Bhattacharyya, Suvanjan
    Drying Science and Technology provides a thorough and current investigation of the complex area of drying processes. This book is a collaborative effort that brings together prominent professionals to give a comprehensive grasp of drying science’s concepts, methodology, and applications. The book opens by underlining the importance of drying operations in a variety of sectors, including food preservation and materials processing. This opening portion provides the framework for a varied investigation that will appeal to a wide range of readers. The book covers fundamental ideas and digs into the heat and mass transport mechanisms that underpin drying processes. Readers are taken through the fundamentals that determine the efficiency and quality of drying processes, laying the groundwork for additional in-depth research. A large portion of the book is dedicated to a variety of drying processes and procedures, both traditional and cutting-edge. From basic convection drying to modern technologies such as freeze drying and microwave drying, each strategy is evaluated for its uses, benefits, and drawbacks. This broad cover guarantees that readers obtain a full understanding of the equipment available for various drying applications. The use of mathematical modeling provides a quantitative dimension to the book, with chapters focused on the development, evaluation, and application of models in drying science. This part is intended for scholars and practitioners who want a better knowledge of the quantitative features that underpin the discipline. The book highlights the dynamic nature of drying research and includes the most recent advances in drying technology. Innovations in equipment and approaches highlight the changing landscape of drying research, providing insights into cutting-edge discoveries that will impact the field’s future. With a balanced combination of theoretical insights and practical applications, Drying Science and Technology is an invaluable resource for students, researchers, and professionals working in the various fields of drying.
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    Effects of a novel hybrid turbulator tape on the thermohydraulic performance and irreversibility of a solar air heater
    (Elsevier, 2024-03) Bhattacharyya, Suvanjan
    Renewable energy from the sun has been a rapidly expanding field in recent years, because to its many advantages as a sustainable, cost-effective, and environmentally friendly power source. Energy drives economic growth and industrialization today. Air heating is a prominent solar energy utilization for space and process heating including washing, desalination, crop drying, and others. To improve energy efficiency, this study examined several designs of novel hybrid tape within an affordable solar-powered air heater. Solar air heaters can improve their heating efficiency by adding additional novel swirl generator. Many research have been done in this subject, however novel geometries are being proposed to better the heat transfer enhancement (HTE)-blowing power penalty tradeoff. Hybrid turbulator tapes are new, and there is no parametric investigation on their advantages. To cover this gap in this research, utilized air as the working fluid to investigate the pressure drop and heat transfer characteristics inside a uniformly heated circular tube with hybrid turbulator tape inserts. The aim was to cover the turbulent flow regime by varying the Reynolds number from 10,104 to 73,788. The thermohydraulic performance with pitch, length, and width ratios is investigated in this work. In comparison to a plain tube, it is observed an average increase of 91% and 39% in the Nusselt number and friction factor, respectively. This indicates a significant improvement in the tube's performance. It is also found that the important thermal performance factor exceeded one for all tape combinations. Novel correlations have also developed. With such encouraging results, using the tested turbulator in a solar air heater for improved performance is feasible.
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    Evaluation of aerothermal performance of a round tube with regularly-spaced multi-channel twisted tape elements installed
    (Springer, 2024-05) Bhattacharyya, Suvanjan
    This article presents a study of aerothermal performance of tubes with regularly-spaced multi-channel twisted tape elements (RS-MTT) installed. This research aimed to find the proper design RS-MTTs that induce swirl flow which potentially improves fluid mixing between the core fluid and the fluid near the tube wall, thereby accelerating the heat transfer rate. Additionally, the effects of Reynolds numbers and free-spacing ratios (s/y) on heat transfer, friction loss, and thermal performance behaviors were examined. The RS-MTTs having different free-spacing ratios (s/y) of 0.0, 0.25, 0.5, 0.75, and 1.0 were tested. Air was utilized as the testing fluid in experiments with Reynolds numbers (Re) spanning from 6000 to 20,000. The utilization of RS-MTTs with s/y = 0.0, 0.25, 0.5, 0.75, and 1.0 augmented heat transfer rates up to 1.74, 1.80, 1.85, 1.90, and 2.15 times given by the plain tube alone while the friction factors increased by 4.22, 4.61, 3.87, and 4.05 times, respectively. At the lowest Reynolds number of 6000, the thermal enhancement factors of the tube containing the RS-MTTs with s/y = 0.0, 0.25, 0.5, 0.75, and 1.0 reached the maximum values of 1.42, 1.35, 1.31, 1.27, and 1.23, respectively. Among the RS-MTTs tested, the RS-MTT with s/y = 0.0 showed the best thermal enhancement factor of 4.56%, corresponding to the heat transfer augmented of 11.52% with a friction penalty of 8.71%.
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    Improving electric vehicle battery cooling efficiency with nanofluid and vibration integration: a novel thermal management approach
    (Springer, 2024-07) Bhattacharyya, Suvanjan
    The cooling system of an electric vehicle can be affected in various ways by vibrations, potentially impacting its performance and reliability. This encompasses damage to the components, potential leaks, noise, and discomfort, which may impact the performance. The impact of vibrations on electric vehicle cooling systems utilizing nanofluids as their primary working fluids remains insufficiently explored. Ongoing research aims to elucidate the specific influence of vibrations on these cooling systems implemented in such vehicles. The study of vibrations with amplitudes of up to 5 mm and frequencies of up to 25 Hz has been conducted. In the numerical model, a 2% volume concentration Al2O3 solution was utilized as the working fluid, with water serving as the base fluid, and Reynolds numbers ranging from 10,000 to 20,000 in the turbulent regime. The present study is focused on performing exergy and entropy analysis utilizing the second law. On inducing vibration onto the system, the Nusselt number rises to a maximum of 170% compared to the static tube. Entropy generation increases with increasing intensity of vibration. A similar trend is observed for second law efficiency which reaches a maximum of 60.81% at 5 mm amplitude and 25 Hz frequency at 20,000 Reynolds number. But with increasing intensity of vibration, dimensionless number of irreversibility () shows a negative trend with a minimum of 0.715 at 25 Hz frequency and 5 mm amplitude of vibration. Introducing controlled vibrations can significantly enhance system availability and efficiency, leading to considerable improvements in energy usage and cost-effectiveness.
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    A critical review on various factors affecting the thermohydraulic performance in transition-flow regime
    (Springer, 2024-06) Bhattacharyya, Suvanjan
    Heat transfer and pressure drop in laminar and turbulent flow have been studied for a long time. However, the thermohydraulic of fluid flow in transition flow is still in the embryonic stage and needs further exploration. Primarily, this article complied all the fragmented research works linked to thermal and flow performance in transition-flow regimes. Several detailed research works pertaining to developing and fully developed transition flow were reported in the past three decades which significantly contribute to the field. It was also found that the transition-flow regime shifted with the change in the operating conditions such as free, forced and mixed convection, developing and fully developed flow, inlet geometries, type of working fluid, channel geometries, roughness, the orientation of test section, etc. Hence, by altering the shape of the entrance, the amount of heat passing through, or the surface of the tube, one could manipulate the range of Reynolds numbers where the transition took place. The temperature of fluids affects their densities, so when heat is applied to the tube wall, it creates temperature differences within the thermal boundary layer. These differences in temperature then cause changes in density and buoyancy due to the force of gravity. Several novel correlations have been developed based on these findings to determine the heat transfer and pressure drop in different flow regimes. In order to develop accurate correlations for heat transfer and pressure drop in the transitional-flow regime, it is necessary to comprehend the factors that impact the beginning and end of this regime. This understanding is crucial for selecting or creating suitable correlations.
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    A move toward environmental sustainability: an analysis of the impact of state-level incentive policy improving the adoption of electric vehicles in India
    (Springer, 2024-10) Bhattacharyya, Suvanjan
    Electric vehicles have been considered as a viable solution to combat the major global issues of increasing energy demands and environmental pollution, and hence are being promoted unceasingly across the world. Several fiscal and non-fiscal policy measures have been proposed and implemented by the Governments to enhance the market share of electric vehicles (EV) significantly. However, their efficacy is subjected to various control parametric scenarios. In India, the EV market is still in its initial stage and has significant acceleration potential. The present work investigates the effectiveness of various state-level promotional schemes in India empirically, using static regression panel data modeling methods. Based on the econometric analysis, the fiscal incentive policy in terms of favorable purchase subsidies and scrapping incentives is reported to be more influential on the consumer side in promoting EV diffusion to the Indian market. Effective charging infrastructure development is also an important aspect to have supportive space in Government monetary support policies. However, policies regarding favorable energy tariff have not been proved so effective at this stage; hence, it is recommended to get reviewed. Further, out of several control factors, literacy rate is observed to be the most influencing factor for significant shift of potential consumer toward adoption of electric vehicles over corresponding conventional alternatives.
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    Thermal and flow dynamics of an inclined air heat exchanger equipped with spring turbulators in the transition flow regime
    (Springer Nature, 2024-11) Bhattacharyya, Suvanjan
    The research involves an experimental investigation into the performance of a flow assisting air heat exchanger under varying angular orientation and uniform external heat fluxes without and with spring turbulators. The investigation was performed for Reynolds numbers ranging from 511 to 9676 and inclination angle 15° and 30°. Three heat fluxes (2, 3, and 4 kW/m2) were applied to the test section to investigate the effect of external surface heating on the range of transition flow regime and thermohydraulic performance. Transition from laminar to turbulent flow for plain channel at different heat fluxes and inclinations occurs within specific Reynolds number ranges: 2436–4446 for 15° inclination at 4 kW/m2, 2574–4289 at 3 kW/m2, and 2850–4152 at 2 kW/m2; for 30° inclination, the ranges are 2518–4151, 2712–4361, and 2992–4346 at the respective heat fluxes. When it comes to the effect of inclination on Nusselt number, the transition occurs sooner at lower angles, but is delayed as the angle increases. Additionally, the Nusselt number decreases as the angle of inclination increases. When comparing the Nusselt numbers of plain tubes to those with spring turbulators, the latter shows a significantly greater enhancement. In laminar flow, a maximum 100% deviation exists between highest and lowest friction factors, decreasing to 75% with increasing Reynolds number; all insert configurations exhibit highest friction factor at 15° due to stronger buoyancy forces.