Comparative CFD analysis of heat transfer enhancement using NACA0021 and NACA2421 aerofoil inserts in turbulent pipe flow Rohit Rajendra Jadhao, Parashuram Chitragar, Dattatray Kamble Energy Sources Part A Recovery Utilization and Environmental Effects, 2026 This study presents a computational fluid dynamics investigation of heat transfer enhancement in turbulent pipe flow using aligned National Advisory Committee for Aeronautics (NACA) aerofoil inserts as passive enhancement devices. Two aerofoil geometries are examined: the symmetric NACA0021 and the asymmetric cambered NACA2421. The inserts are mounted in a circular pipe of 25 mm diameter and 500 mm length, with five full-span aerofoils of 25 mm chord length uniformly distributed along the flow direction and oriented in an aligned configuration at zero angle of attack. The Steady state simulations are performed at Reynolds numbers 20,000 and 60,000 based on the Realizable k–ε model with the enhanced wall treatment model. Thermal and hydraulic performance parameters including heat transfer rate, flow resistance and overall thermal efficiency are evaluated and compared. The results indicate that the asymmetric NACA2421 insert provides higher heat transfer enhancement than the symmetric NACA0021 due to stronger secondary flow generation and improved boundary layer disruption. Although both configurations lead to increased pressure drop compared to a plain pipe, the overall thermal performance remains favorable which particularly for the asymmetric insert at higher flow rates. The findings demonstrate that aligned aerofoil inserts offer an effective and practical approach for enhancing thermal performance in compact and energy-efficient heat exchanger systems.
Overview of the future perspective of aerofoil-based passive heat transfer enhancement Rohit Rajendra Jadhao, Parashuram Chitragar, Dattatray Kamble Engineering Research Express, 2025 With increasing demands for sustainability and energy efficiency in various industrial applications, inefficient heat transfer systems have received much attention. This abstract provides an ability that involves aerofoil-based passive heat transfer enhancement. Aerofoil-shaped structures inspired by aerodynamic principles have shown promise to enhance heat transfer without the need for external power sources. Understanding the capabilities and challenges of aerofoil-based passive approaches is important for the advancement of thermal management in a variety of applications including aerospace, industrial applications, renewable energy systems, electronics cooling and automotive systems. The study examines various geometries, materials, and configurations to determine their effect on heat transfer efficiency. The mechanisms that promote heat transfer in aerofoil-like structures are examined. The outcome overview encompasses important findings from research exploring the application of aerofoil systems to enhance passive heat enhancement. It evaluates the effectiveness of different aerofoil geometries for heat enhancement performance by providing a comparative review analysis of parameters such as heat transfer coefficient, Nusselt number and thermal resistance in different passive enhancement techniques. The results show that NACA 4412 formulas reaches achieve superior heat transfer rates with its turbulence increases friction factor boundary layer decomposition. Asymmetric profiles promote better heat transfer than symmetric profiles, despite the considerable loss. When compared to alternative methods like twisted tapes and vortex generators, the thermal efficiency of aerofoil inserts in lowering pressure is low. Future advancements could include 3D design, smart materials, and hybrid configurations, which would offer crucial new data for the design of industrial heat exchangers. The conclusion of this study offers a look ahead at the possibilities for improving passive heat transfer using aerofoils. The findings show that forms such as aerofoils can greatly improve thermal performance across a number of industries. According to these findings, more research and development are necessary to solve current issues and fully utilise passive aerofoil-based techniques. The insights presented in this overview are intended to guide researchers, engineers, and policymakers in the application of aerofoil-based methods for large-scale thermal systems in the upcoming years.
A chronological review of heat transfer enhancement using inserts in channel flows Rohit Rajendra Jadhao, Parashuram Chitragar, Dattatray Kamble Physica Scripta, 2025 Heat transfer enhancement has become an important research area to improve the efficiency of thermal systems. This chronological review focuses on approaches for heat transfer enhancement by incorporating inputs into strategies. An in-depth review has been carried out with inserts such as twisted tapes, turbulators, vortex generators, dimple surfaces and porous materials to improve heat transfer in a variety of applications like heat exchangers, renewable energy devices, automotive systems and electronic cooling systems. A comprehensive literature review across several decades was conducted to examine the progress in improving heat transfer efficiency. Various numerical, analytical and experimental methods used in the study were examined to correct the processes and effects of different insert designs. The study includes various insert geometries, structures and materials providing a detailed analysis of the state-of-the-art in heat transfer enhancement. The review highlights key findings from studies of various inputs and their effects on heat transfer enhancement. It provides insight into efficiency metrics such as the Nusselt number, coefficient of heat transfer and pressure drop associated with each insertion method. In addition, the chronological presentation allows trends and improvements to be identified in insert-based heat transfer enhancement over the years. The results in various applications show the effectiveness of certain insert geometries and configurations in improving heat transfer performance. This chronological analysis provides a comprehensive overview of the progress in heat transfer enhancement through the use of different approaches. Knowledge gathered from various studies demonstrates the potential of insert-based methods to significantly improve the thermal conductivity of various thermal systems. Insights gained from this study can guide future research efforts, contributing to efficient and sustainable heat transfer technologies that have been developed. The conclusion highlights the importance of continued research in this area to address the growing challenges of thermal management and energy efficiency.
COMPARATIVE ANALYSIS OF AEROBEADS AND AEROFOIL SHAPES FOR HEAT TRANSFER ENHANCEMENT IN HEAT EXCHANGER SYSTEMS Rohit Rajendra Jadhao, Parashuram Chitragar, Dattatray Kamble ASME International Mechanical Engineering Congress and Exposition Proceedings Imece, 2025 The performance and efficiency of heat exchangers are crucial for various industrial applications like power generation, chemical processing and refrigeration. As the global energy demands increase which enhancing the heat transfer characteristics of these systems has been a priority in order to achieve greater energy efficiency and sustainability. In current study highlighting the two novel geometrical enhancement insert techniques which namely aerobeads and aerofoil inserts are compared as methods of improving heat transfer in heat exchanger systems. Aerobeads are small in spherical structures that break the thermal boundary layer and cause turbulence; which are very effective for heat transfer enhancement under turbulent flow conditions. On the other hand, aerofoil shaped inserts are motivated by streamlined aerofoil geometries which produce controlled secondary flows and vortices are more suitable for laminar flow regimes. These designs provide unique ways to enhance heat exchanger performance but their potential characteristics have not been systematically compared. A comprehensive investigation has been conducted using an experimental and computational approach to address this gap. The experimental setup includes instrument for the measurements of fluid velocity, inlet and outlet temperatures and pressure drops across the pipe test section. Aerobeads and aerofoil inserts are tested separately in identical flow conditions to allow direct comparison. Advanced Computational Fluid Dynamics (CFD) simulations are realized with governing equations of continuity, momentum and energy in which turbulence is simulated by means of the k-ε model. High-resolution structured meshes have been used to capture small geometrical complexities of aerobeads and aerofoils to ensure accurate simulation of fluid dynamics and heat transfer phenomena. The studies evaluation metrics included the Nusselt number which represent the heat transfer effectiveness, the friction factor, the flow resistance, pressure drop penalties and the thermal performance factor to integrate both the heat transfer and the pressure drop into an overall performance measure. Results indicated that aerobeads made a significant enhancement of 35% in the Nusselt number compared with the plain tube especially excelling in turbulent flow regimes because they caused strong turbulence and helped in breaking thermal boundary layers. However, this enhancement came at the expense of a significantly greater pressure drop and higher friction factors which raising concerns regarding energy efficiency in real-world applications. In other hands aerofoil inserts is improved Nusselt number by 25% at a much more with moderate increase in the friction factor. An aerofoils streamlined develop lessens flow resistance which providing a more balanced solution particularly in laminar flow regimes where pressure drop penalties must be controlled. The comparison investigation revealed that while aerobeads perform better than aerofoils in turbulent flows where the aerofoils often have a higher thermal performance factor which suggesting a better choices between pressure drop and heat transfer enhancement. The study also validated the experimental findings with computational results which showed a maximum deviation of 5% thereby proving the reliability of the methodologies used. These findings provide valuable insights for the optimization of heat exchanger designs which enabling modified solutions based on specific operational requirements. For applications involving primarily turbulent regimes in which aerobeads geometries would be advisable. Alternatively, laminar flow applications may be better optimized using aerofoil inserts. Moreover, there is an important potential for the development of future hybrid designs by which aerobeads like creating turbulence could be exploited in conjunction with aerodynamic efficiency with aerofoil type characteristics to realize novel levels of performance. Thus, the present research provides a strong understanding and exploiting advanced geometrical augmentation in heat exchanger systems. In order to address a significant research gap and provide useful information for a wide range of industrial applications which examines aerobeads and aerofoils deliberately under highly controlled conditions. However, these results provide us a single step closer to developing heat exchanger systems that are more sustainable and efficient.
Influence of water-methanol injection and turbocharging on the performance of a hydrogen-fueled spark ignition engine P. R. Chitragar, K. V. Shivaprasad, Manjunath Ichchangi, Rajesh Ravi, M. S. Yadav, G. N. Kumar Environmental Quality Management, 2024 This article presents a study that compares the performance and emission characteristics of a four‐stroke, four‐cylinder spark ignition (SI) engine fueled by gasoline and neat hydrogen. The engine was equipped with turbocharging to optimize ignition timing for power boosting and vaporized water–methanol injection to reduce emissions. Engine tests were conducted at speeds ranging from 2000 to 6000 rpm, with a fixed intake pressure and varying quantities of hydrogen and spark advance timings. The study compared the results of non‐turbocharged and turbocharged engines with water–methanol injection in terms of combustion, performance, and emissions. The findings showed that the turbocharged water–methanol hydrogen operation had a higher brake thermal efficiency (BTE) than its counterpart, while the brake power of the hydrogen engine operation increased with turbocharging but slightly decreased with water–methanol injection. Additionally, volumetric efficiency improved by 7% for turbocharged and 4% for water‐injected hydrogen engine operation compared to the counterpart. The cylinder pressure for turbocharging with water–methanol operation yielded 16.32% higher compared with counterpart gasoline engine operation. Finally, nitrogen oxides (NOx) emissions were reduced with turbocharging and water–methanol injection compared to the counterpart non‐turbocharged hydrogen engine operation.
Investigation on performance, combustion and emission characteristics of 4-stroke four cylinder hydrogen fuelled SI engine Parashuram R. Chitragar, K. V. Shivaprasad, M. S. Gaikwad, G. N. Kumar Aip Conference Proceedings, 2021 In respect of depletion of fossil fuel and its harmful effect on the environment, research on alternative fuel engines has fascinated large attention from the engine society. Among the several options considered today, hydrogen conceivably the ideal fuel in view of its immeasurable clean-burning qualities, source availabilities and thus promises to be the greatest potential fuel. This article explores the investigation on combustion, performance and emission characteristics of four-cylinder, four-stroke spark ignition (SI) engine experimentally. Tests were carried out by using pure gasoline and pure hydrogen by different loads and speeds at static ignition timing of 5-degree crank angle before top dead center (deg. CA bTDC). The experimental study discovered the decrement in brake power along with volumetric efficiency and increment in brake thermal efficiency with hydrogen fuel engine operation compared to gasoline operation. In-cylinder pressure is notably increased with hydrogen and peak pressure was shifted towards TDC in comparison with gasoline engine operation. The net heat release rate is enhanced with neat hydrogen engine operation compared to gasoline. The emissions of carbon monoxide (CO), hydrocarbons (HC) were condensed and a nitrogen oxide (NOx) was amplified for hydrogen compared to gasoline engine operation.
Combustion characteristics of biomethane–diesel dual-fueled CI engine with exhaust gas recirculation Machindra S. Gaikwad, Keshav M. Jadhav, Avinash H. Kolekar, Parashuram R. Chitragar Biofuels, 2021 In this investigation biomethane and diesel fuel were used in a compression ignition (CI) engine with a dual fuel mode of operation. Biomethane is induced along with the intake air stream while diesel fuel is injected in a conventional way. Experiments were carried out on an exhaust gas recirculation (EGR)-equipped CI engine (single cylinder, four stroke, water cooled). The main goal of this investigation is to study the combustion characteristics of a biomethane–diesel fuel combination in dual fuel mode of a CI engine. The EGR system is also used in the dual fuel mode of operation to determine its effects. Cylinder pressure, rate of pressure rise, and heat release are the combustion parameters examined. Experimental results showed that all combustion parameters give lower values in the dual-fuel mode of operation compared to straight diesel operation. EGR again reduces the values of combustion parameters in dual-fuel mode.
Effect of hydrogen addition on combustion and emissions performance of a high speed spark ignited engine at idle condition Kumar Vijayalakshmi Shivaprasad, P.R. Chitragar, Gottigere Narayanappa Kumar Thermal Science, 2018 The fuel depletion and environmental pollution have pushed studies on improving the combustion and emission characteristics of internal combustion engines with several alternative fuels. Expert studies proved that hydrogen is one of the prominent energy source which has exceptional combustion qualities that can be used for improving combustion and emissions performance of gasoline-fueled spark ignition engines. This paper introduced an experiment conducted on a single cylinder high speed gasoline engine equipped with a hydrogen injection system to discover the combustion and emissions characteristics with various hydrogen gasoline blends at idle condition. For this purpose, the conventional carburetted high speed spark ignition engine was modified into an electronically controllable engine with help of electronic control unit which dedicatedly used to control the ignition timings and injection duration of gasoline fuel.
Influence of spark timing on the performance and emission characteristics of gasoline–hydrogen-blended high-speed spark-ignition engine K. V. Shivaprasad, Parashuram R. Chitragar, Vignesha Nayak, G. N. Kumar International Journal of Ambient Energy, 2017 This article experimentally investigates the effect of spark timing on performance and emission characteristics of high-speed spark-ignition (SI) engine operated with different hydrogen–gasoline fuel blends. For this purpose, the conventional carbureted SI engine is modified into an electronically controllable engine, wherein an electronically controllable unit was used to control the ignition timings and injection duration of gasoline. The tests were conducted with different spark timings at the wide open throttle position and 3000 rpm engine speed. The experimental results demonstrated that brake mean effective pressure and engine brake thermal efficiency increased first and then decreased with the increase in spark advance. Peak cylinder pressure, temperature and heat release rate were increased until 20% hydrogen addition and with increased spark timings. NOx emissions were continuously increased with the increment in both spark timings and hydrogen addition, whereas hydrocarbon emissions were increased with spark timings but decreased with hydrogen addition. CO emissions were reduced with the increase in spark timing and hydrogen addition.
Hydrogen addition on combustion and emission characteristics of high speed spark ignition engine- An experimental study Journal of Engineering Science and Technology, 2016
