Department of Mechanical engineering

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Author: search.filters.author.Soni, Manoj KumarHas files: No

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    The influence of a novel ribbed wave tape on the enhancement of heat transfer in a solar air heater operating in a transitional flow regime: an experimental study
    (Taylor & Francis, 2023-10) Bhattacharyya, Suvanjan; Soni, Manoj Kumar
    The effect of a novel ribbed wave tape on the augmentation of heat transfer in a solar air heater operating in a transitional flow regime is experimentally examined. Three different wave ratios are used, and the tube is uniformly heated using heat fluxes while the Reynolds number varied from 521 to 10,194. The transition for plain tube begins at 2810 and ends at 3724. For tube with ribbed wavy tapes, transition begins early and ends at higher Reynolds number than plain tube. For 2 kW/m2 of heat flux, the transition for wavy tape having wave ratio 3 begins at Reynolds number 2589 while at heat flux of 4 kW/m2, the transition begins at Reynolds number 2745. The end of transition takes place at Reynolds number 3969 and 4139 for wave ratio 3 at heat fluxes 2 and 4 kW/m2, respectively. The length of transition decreases with increase in the wave ratio at uniform heat flux. The average enhancement in Nusselt number for ribbed wavy tapes having wave ratio 3 at 4 kW/m2 heat flux was 262% and 85% for laminar and turbulent flow regime, respectively. Two empirical correlations were developed to predict the Nusselt number and friction factor for all the flow regimes.
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    Transitional mixed convection in inclined solar air heater tube with wavy inserts
    (Taylor & Francis, 2025-03) Bhattacharyya, Suvanjan; Soni, Manoj Kumar
    This study experimentally explores the influence of inclination angle and wavy tape inserts on mixed convection heat transfer and pressure drop in a solar air heater tube. Experiments at 15° and 30° inclinations, with Reynolds numbers from 455 to 6059 reveal that increasing inclination reduces heat transfer and pressure drop. Transition Reynolds numbers vary with heat flux levels: 3 kW/m2 (2528-3793), 2 kW/m2 (2520-3801), and 1 kW/m2 (2627-3848). The Colburn factors in the laminar and transition flow regimes shows distinct characteristics but converge in turbulent flow. The wavy tape with a width ratio of 0.8 and a wave ratio of 0.75 exhibits the highest Colburn factor and friction factor, while a width ratio of 0.6 and a wave ratio of 2.25 lead to minima of these values. With increase in the inclination, the effect of buoyancy forces starts decreasing. This leads to reduced disturbance compared to a lower angular position. Novel correlations were also developed for predicting the Colburn and friction factors.
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    Experimental investigation of twisted tape-induced mixed convection for optimized thermofluidic performance in transitional flow regimes
    (Elsevier, 2025-05) Bhattacharyya, Suvanjan; Soni, Manoj Kumar
    The current study aims to experimentally investigate the thermohydrodynamics coaction in a solar air heater tube equipped with twisted tape turbulators, specifically focusing on laminar and transitional flow regimes. This study uses air with Reynolds numbers (Rea) from 563 to 10,240. Wall heat flux (q) is uniform on heat exchanger tube. On the tube surface, “2, 3, and 4” kW-m−2 heat fluxes are used. Twisted tapes with twist ratios (y) “3, 4 and 5” were used as passive heat transfer enhancement devices. The results of heat transfer are presented in terms of Nusselt number (Nua) and Colburn j-factor (j) while the pressure drop is presented as friction factor (f). The results revealed changes in the transition boundary. For plain channel being subjected to uniform heat flux of 3 kW-m−2, the transition begins at Rea equals to 2595 and ends at Rea 3833. For twisted tape having twist ratio 3 at 4 kW-m−2 heat flux, the improvement in the heat transfer was highest. Similar results were obtained for f. Four empirical correlations were developed for predicting the Nusselt number (Nua) and friction factor (f), achieving deviations as low as ±0.75 % from experimental data. These correlations provide highly reliable guidance for optimizing heat exchanger design and performance.
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    Evaluating the heat transfer and pressure drop in the transitional flow regime for a horizontal circular tube fitted with wavy-tape inserts
    (Elsevier, 2024-02) Bhattacharyya, Suvanjan; Soni, Manoj Kumar
    Much research is available to support the thermo-hydraulic characteristics of heat exchanger tubes in laminar and turbulent flow regimes. However, very little work is available to support the thermohydraulic characteristics of heat exchangers in transition flow regimes, especially in turbulators. Therefore, this research experimentally evaluated the heat transfer and pressure drop characteristics of a circular tube fitted with wavy-tape inserts in the transition flow regime. Experiments were conducted in a circular tube having an internal diameter of 20 mm and a length of 2000 mm and the Reynolds number varied from 533 to 7002. The Nusselt number and friction factor for a smooth tube are validated by comparison with published research works in the laminar and turbulent flow regimes. A total of nine wavy tape inserts with different wave and width ratios were investigated. To determine the variation of Nusselt number and friction factor, three constant heat fluxes ( 1, 2, and 3 kW/m2) were applied to the test section. The laminar, transition, and turbulent regimes were marked and identified by using the linear best-fit line method for all the cases considered during the investigation. The results obtained from the study showed a shift in the boundaries of laminar, transition, and turbulent flow regimes. For smooth tube with 1 kW/m2 heat flux, the transition starts and ends at Reynolds number 2202 and 3 804, respectively. It was also revealed that the onset of transition occurred further earlier when tapes were used. The boundaries of transition also shifted with a change in the constant heat flux condition. For wavy tape having w = 0.75, d = 0.8, the transition begins at Reynolds number 2 193, 2 021, 2029 and ends at 4 016, 3 997, 3989 for heat flux 1, 2 and 3 kW/m2, respectively. The transition began earlier for lower values of heat flux, while for higher values, the transition limit was delayed compared with that of lower heat flux. The boundary of transition also shifted with wave ratio and width ratio. An increase in wave and width ratios altogether delayed the start and end of the transition. Correlations were also developed to predict the Nusselt number and friction factor in laminar and turbulent flow regime.
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    Design and Development of Game Based Evaluation and Learning (GABEL) for Applied Thermodynamics course for Active Learning
    (IEOM Society International, 2019-03) Soni, Manoj Kumar
    This article describes the application of Game based Evaluation and Learning in the classroom for formative assessment. The author caters large class of 194 second year students in Applied Thermodynamics course and evidence showed that this game enhances students’ attendance and learning in the course. The students got motivated to learn the course as it is active learning which much better as compared to the regular rote learning. The amalgamation of gamification as part of evaluation tasks is a complex process in active learning. It takes into attention not only the surrounding or motivational aspects of the activity, but also the quality criteria that are compulsory from the evaluation perspective. In the course, the Stock Market game was designed and customized for the active learning and evaluation in a structured fashion. In order to assess the effectiveness of it a survey was conducted. This activity received accolade from the students.
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    Analysis of Course Content Development using Pedagogic Framework – A Case Study
    (IEOM Society International, 2019) Soni, Manoj Kumar
    The article delineates a scaffold for analyzing the outcome based course objectives and ascertain the variance among unit, module and course level objectives with reference to the Bloom’s taxonomy using pedagogic framework. It also investigates the correlation across the objectives at the course, module and unit levels. The key emphasis of the study is to develop a methodology to help the developer write objectives in an appropriate manner in engineering education system.
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    Heat Transfer and Pressure Drop in Transitional Flow: A Short
    (IOP, 2021) Soni, Manoj Kumar; Bhattacharyya, Suvanjan
    In the present work, an effort has been made to present the short review of all the numerical as well as experimental studies done in the field of heat transfer and pressure drop in the transitional flow regime. The experimental and numerical studies on transition flow are reported. Though, there are several challenges to do experiments in transition flow regime. Various techniques are also discussed and summarized. Results show that the techniques prove outstanding performance, but few methods quiet suffer from high pressure drop. As per discussion, new viewpoints on the current research gaps and future research ways have been providing for the development of heat transfer techniques.
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    Solar Thermal Based Trigeneration System: Simulation and Design
    (The InfoLibrary, 2022) Soni, Manoj Kumar
    Use of solar thermal devices has proved a viable option for power generation in many countries that have abundant solar radiation throughout the year. Power Tower and Parabolic Trough collectors are the most common and commercially proven technologies in such solar thermal power plants. This paper presents the design and simulation of 1 MWe solar thermal power plant in which the steam is generated by Australian Nation University’s (ANU) 520 m2 solar parabolic dish concentrators. The plant also powers a vapour absorption-chilling unit that uses steam extracted from the turbine to produce a cooling effect. This paper discusses the design of the power cycle, and through the simulation, estimates the annual power generation from the power block and tonnes of refrigeration produced by vapour absorption chiller. Apart from the design of the power cycle, the layout of dishes is also designed for maximum steam generation from the solar field. The waste heat from the vapour absorption system may be used for low-grade heating applications
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    Semi-process Industry and Lean Manufacturing
    (The InfoLibrary, 2022) Soni, Manoj Kumar
    This paper aims at proving that lean manufacturing can be successfully implemented in a semi-process industry, to reduce defects, waste, waiting time, processing time, inventory, and space.Acase studywas performed on a medium sized ceramic industry which resulted in waiting time reduction by 32%, processing time reduction by 1.02%, reduction in inventory by 36%, defects reduction (average) by 40.51%, reduction in manpower by 6.85% and cost saving of US $ 0.61 million in one financial year. It might represent new opportunities for lean practitioners/researchers who are interested in substantiating their lean endeavors in semi-process industries
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    Solar Energy Related Course and Instructional Design: Integrating Experiential and Collaborative Learning
    (The InfoLibrary, 2018) Soni, Manoj Kumar
    The conventional teaching method is mostly as a one-way communication be-tween instructor and students, where students go through rote learning and then appear for written exam. Based on their performance in written exam they are graded and judged. This type of system inculcates exam oriented learning approach than to actual knowledge gain. This is a major issue in the present era where students are fed up with exam oriented approach. So there is immense need to bring innovation in teaching methods. Also, along with education, among the students, there is need of growing social awareness specially towards weaker section of society. In order to impart effective learning experiential and collaborative learning has been incorporated in solar energy related courses by the authors at BITS Pilani. During these courses, the students fabricated do-it-yourself type solar cookers and tested the performance of these cookers in normal conditions. In order to have feel of the usage of the fabricated cookers the students were asked to cook some food items using those cookers. After successful completion of these activities, with the help of a NGO students helped the authors to conduct cheap solar cooker workshop for villagewomen at a village near the institute. During theworkshop the students helped the village women to fabricate cheap solar cookers. All the activities fabrication, testing and involvement in the workshop was the part of evaluative components for the courses. It was overall a very successful experiential and collaborative learning experiment with social angle involved in it.