SIVAKUMAR RAMASAMI

Scopus Publications

Effects of swirl on nonreacting and reacting flows in a single-element lean direct injection combustors
Rajesh Mavuri, R. Sivakumar
Aircraft Engineering and Aerospace Technology, 2025
Purpose The swirl intensity imposed on the flow plays a vital role in aerodynamics, flame shape, flame stabilization and combustion intensity. In lean direct injection (LDI), the air and fuel are fed through separate channels, and the swirling air flows have a strong impact on fuel-air mixing and heat release. The literature indicates that the effects of swirling on helical axial LDI systems are limited to nonreacting flows studied through experimental methods, but not many studies have been reported on the reacting flows of a single swirler. The objectives of the paper are divided into two parts. The first part presents the role of swirl in nonreacting LDI systems and the second part describes spray combustion in LDI systems for low (swirl < 0.5) to high (swirl > 0.5) swirl numbers. Design/methodology/approach The numerical model incorporates all the necessary features of the single helical axial swirler, starting from the hollow circular section to the outlet of a long mixing chamber. The commercial solver FLUENT is used to predict the flow field around the axial swirler. The first step is to establish a numerical procedure (based on computational fluid dynamics [CFD]) to predict the nonreacting flow behavior for different swirlers and the CFD results are validated against literature data. The spray atomization, droplet evaporation and the effects of interaction between the two phases are modeled by implementing various spray submodels in FLUENT. The large Eddy simulation (LES) reacting flow results for a vane tip angle of 60° are compared with test data and presented at multiple cross planes. Findings The numerical simulations were carried out on a nonreacting single helical axial swirler for various vane tip angles, such as 40°, 50°, 55, and 60°, and the results were validated against test data. The centerline mean axial velocity and radial velocity profiles at several axial locations are in good agreement with the literature data. For reacting swirling flows, the experimental data is available only for a 60° vane tip angle. The S60 reacting flow LES mean predictions are compared at different cross planes. The axial momentum increases due to the liquid spray combustion in the gas phase and the reacting flow central recirculation zone is substantially shorter than the nonreacting flow. The impact of spray atomization due to interaction with the gas phase is verified, and the droplet mean diameter trends are consistent across different cross planes. The LES predictions of reacting flows for low to high swirls are investigated, and the effects on combustion performance are summarized. Originality/value The novelty of the paper is highlighted in two key conclusions. First, the paper presents numerical methods for studying the role of swirl in a nonreacting LDI system and validates the results against experimental data. Second, the effects of combustion on the gas phase, spray combustion modeling and droplet atomization are numerically established and compared with literature data for a 60° vane tip angle. In addition, the role of swirl in the reacting flow field for vane tip angles of 40°, 50° and 60° is numerically investigated, and its effect on flame stability, pressure drop and NOx emissions is presented. The paper describes LES grid guidelines for the LDI swirler and presents a numerical modeling approach that helps to develop a robust swirler design through a parametric investigation of swirler geometry. The methodology can be extended to study multi-element swirler configurations, to understand the effect of swirl on droplet breakup, momentum exchange with adjacent swirlers, flame propagationand emissions.
Implementation of Bitwise Logic Operations using 8T SRAM Cells for In-Memory Computing
Prasanna Venkatesh S, Rohith Sivakumar, Ashwin J S, Sasipriya P, Anita Angeline A
2025 1st International Conference on Intelligent Computing and Systems at the Edge Icedge 2025, 2025
System Design, Optimization and 2nd Law Analysis of a 100 MWe Double Reheat s-CO2 Power Plant at Full Load and Part Loads
Sreekanth Manavalla, Feroskhan M., Joseph Daniel, Sivakumar Ramasamy, T. M. Yunus Khan, Rahmath Ulla Baig, Naif Almakayeel, Bhanu Kiran Voddin Tirumalapur
Sustainability Switzerland, 2023
Super-critical Carbon dioxide (s-CO2) power plants are considered to be efficient and environmentally friendly compared to the traditional Rankine cycle-based steam power plants and Brayton cycle-based gas turbine power plants. In this work, the system design of a coal-fired 100 MWe double reheat s-CO2 power plant is presented. The system is also optimized for efficiency with turbine inlet pressures and the recompression ratio as the variables. The components needed, mass flow rates of various streams and their pressures at various locations in the system have been established. The plant has been studied based on 1st and 2nd laws at full load and at part loads of 80%, 60% and 40%. Operating parameters such as mass flow rate, pressure and temperature have considerably changed in comparison to full load operation. It was also observed that the 1st law efficiency is 53.96%, 53.93%, 52.63% and 50% while the 2nd law efficiency is 51.88%, 51.86%, 50.61% and 48.1% at 100%, 80%, 60% and 40% loads, respectively. The power plant demonstrated good performance even at part loads, especially at 80% load, while the performance deteriorated at lower loads. At full load, the highest amount of exergy destruction is found in the main heater (36.6%) and re-heaters (23.2% and 19.6%) followed by the high-temperature recuperator (5.7%) and cooler (4.1%). Similar trends were observed for the part load operation. It has been found that the recompression ratio should be kept high (>0.5) at lower loads in order to match the performance at higher loads. Combustion and heat exchange due to finite temperature differences are the main causes of exergy destruction, followed by pressure drop.
Condition monitoring of FSW tool using statistical approach
Balachandar Krishnamurthy, Jegadeeshwaran Rakkiannan, Lakshmipathi Jakkampatti, Saravanakumar Devaraj, Senthilkumar Marikannan, Sivakumar Ramasamy
Aip Conference Proceedings, 2023
Custom-built patient specific 3D printed antimicrobial cast for vulnerable fractures
Himanshu Dubey, Himanshu Tanwar, Tushar Dhiman, Raghukiran Nadimpalli, Lakshmipathi Jakkamputi, Senthilkumar Marikkannan, Sivakumar Ramasamy
Aip Conference Proceedings, 2023
Determination of Optimum Outlet Slit Thickness and Outlet Angle for the Bladeless Fan Using the CFD Approach
Vedant Joshi, Wedyn Noronha, Vinayagamurthy G., Sivakumar R., Rajasekarababu K. B.
Energies, 2023
Bladeless fans are more energy efficient, safer due to the hidden blades, easier to clean, and more adjustable than conventional fans. This paper investigates the influence of the airfoil’s outlet slit thickness on the discharge ratio by varying the outlet slit thickness of an Eppler 473 airfoil from 1.2 mm to 2 mm in intervals of 0.2 mm by using a k-omega SST turbulence model with an all y+ wall treatment used to numerically simulate in CFD. The computational results indicated that smaller slits showed higher discharge ratios. The airfoil with a 1.2 mm slit thickness showed a discharge ratio of 18.78, a 24% increase from the discharge ratio of the 2 mm slit. The effect of outlet angle on the pressure drop across the airfoil was also studied. Outlet angles were varied from 16° to 26° by an interval of 2°. The airfoil profile with a 24° outlet angle showed a maximum pressure difference of 965 Pa between the slit and leading edge. In contrast, the 16° outlet angle showed the least pressure difference of 355 Pa. Parameters such as average velocity (U), turbulent kinetic energy, the standard deviation of velocity, and outlet velocity magnitude are used to assess the performance of airfoil profiles used in bladeless fan.
Performance Evaluation of Evacuated Tube Containing Heat Pipe Solar Collector-Based Solar Dryer
Adarsh Abi Mathew, R. Anandu Krishna, R. Sivakumar, T. Venugopal
Lecture Notes in Mechanical Engineering, 2023
LES predictions of confinement effect on swirling flow generated by single helical axial swirler
Mavuri Rajesh, Sivakumar R.
Aircraft Engineering and Aerospace Technology, 2022
Purpose For higher swirling flows (swirl > 0.5), flow confinement significantly impacts fluid flow, flame stability, flame length and heat transfer, especially when the confinement ratio is less than 9. Past numerical studies on helical axial swirler type systems are limited to non-reacting or reacting flows type Reynolds averaged Navier Stokes closure models, mostly are non-parametric studies. Effects of parametric studies like swirl angle and confinement on the unsteady flow field, either numerical or experimental, are very minimal. The purpose of this paper is to document modeling practices for a large eddy simulation (LES) type grid, predict the confinement effects of a single swirler lean direct injection (LDI) system and validate with literature data. Design/methodology/approach The first part of the paper discusses the approach followed for numerical modelling of LES with the minimum number of cells required across critical sections to capture the spectrum of turbulent energy with good accuracy. The numerical model includes all flow developing sections of the LDI swirler, right from the axial setting chamber to the exit of the flame tube, and its length is effectively modelled to match the experimental data. The computational model predicts unsteady features like vortex breakdown bubble, represented by a strong recirculation zone anchored downstream of the fuel nozzle. It is interesting to note that the LES is effective in predicting the secondary recirculation zones in the divergent section as well as at the corners of the tube wall. Findings The predictions of a single helical axial swirler with a vane tip angle of 60°, with a duct size of 2 × 2 square inches, are compared with the experimental data at several axial locations as well as with centerline data. Both mean and unsteady turbulent quantities obtained through the numerical simulations are validated with the experimental data (Cai et al., 2005). The methodology is extended to the confinements effect on mean flow characteristics. The time scale and length scale are useful parameters to get the desired results. The results show that with an increase in the confinement ratio, the recirculation length increases proportionally. A sample of three cases has been documented in this paper. Originality/value The novelty of the paper is the modelling practices (grid/unsteady models) for a parametric study of LDI are established, and the mean confinement effects are validated with experimental data. The spectrum of turbulent energies is well captured by LES, and trends are aligned with experimental data. The methodology can be extended to reacting flows also to study the effect of swirl angle, fuel injection on aerodynamics, droplet characteristics and emissions.
Experimental and Computational Vibration Analysis for Diagnosing the Defects in High Performance Composite Structures Using Machine Learning Approach
Lakshmipathi Jakkamputi, Saravanakumar Devaraj, Senthilkumar Marikkannan, Sakthivel Gnanasekaran, Sivakumar Ramasamy, Jegadeeshwaran Rakkiyannan, Yigeng Xu
Applied Sciences Switzerland, 2022
Delamination in laminated structures is a concern in high-performance structural applications, which challenges the latest non-destructive testing techniques. This study assesses the delamination damage in the glass fiber-reinforced laminated composite structures using structural health monitoring techniques. Glass fiber-reinforced rectangular laminate composite plates with and without delamination were considered to obtain the forced vibration response using an in-house developed finite element model. The damage was diagnosed in the laminated composite using machine learning algorithms through statistical information extracted from the forced vibration response. Using an attribute evaluator, the features that made the greatest contribution were identified from the extracted features. The selected features were further classified using machine learning algorithms, such as decision tree, random forest, naive Bayes, and Bayes net algorithms, to diagnose the damage in the laminated structure. The decision tree method was found to be a computationally effective model in diagnosing the delamination of the composite structure. The effectiveness of the finite element model was further validated with the experimental results, obtained from modal analysis using fabricated laminated and delaminated composite plates. Our proposed model showed 98.5% accuracy in diagnosing the damage in the fabricated composite structure. Hence, this research work motivates the development of online prognostic and health monitoring modules for detecting early damage to prevent catastrophic failures of structures.
Application of Artificial Immune Recognition System for Monitoring the Brake System Using Vibration-Based Statistical Learning
R. Jegadeeshwaran, G. Sakthivel, D. Saravanakumar, T. M. Alamelu Manghai, R. Sivakumar
IEEE Consumer Electronics Magazine, 2022
Infotainment system is one of the standard elements used in all ranges of motor vehicles. These elements act as driver assistance systems that offer numerous advantages to the drivers to ensure safe driving. The infotainment systems indicate the monitoring information based on which the preventive measures can be initiated. In this study, we made an attempt to display the faults that occur in a brake system using vibration analysis through an artificial intelligence technique called artificial immune recognition system (AIRS). The vibration signals captured under various brake faults were processed and the statistical information was extracted. Three versions of the AIRS were used for the classification. Compared to AIRS 1 and AIRS 2 parallel, the AIRS 2 version produced the maximum accuracy of 97.82%. Based on the outcome, an electronics-based diagnostic module is proposed for categorizing and displaying the nature of brake faults in the infotainment system.
Regression-Analysis-Based Empirical Correlations to Design Regenerative Flow Machines
Feroskhan M., Sreekanth M., Karunamurthy K., Sivakumar R., Nazaruddin Sinaga, T. M. Yunus Khan
Energies, 2022
CFD investigation of shock boundary layer interaction in hypersonic flow and flow control using micro ramps
Gautam Gupta, Akshay Ashok Kumar, R. Sivakumar, Jayaraman Kandasamy
Aircraft Engineering and Aerospace Technology, 2022
Fixed displacement gerotor oil pump (FDOP): a survey
V.T. Gannesh, R. Sivakumar, G. Sakthivel
International Journal of Ambient Energy, 2022
Computational investigations of battery thermal management system with environmental effects employing a combination of phase change materials and forced air cooling
R. Pradeep, T. Venugopal, R. Sivakumar
International Journal of Green Energy, 2022
Numerical evaluation of geometric variations in internally heated melt pool
Akash Venkateshwaran, K. Mahendhar Kumar, M. Sai Santosh Pavan Kumar, R. Sivakumar, M.B. Shyam Kumar
Materials Today Proceedings, 2022
Strength analysis of a regenerative flow compressor and a pump based on fluid-structure coupling
Mahendhar Kumar, Akash Venkateshwaran, Machavolu Sai Santhosh Pavan Kumar, Manavalla Sreekanth, Davidson Jebaseelan, R. Sivakumar
Materials Today Proceedings, 2022
Regenerative flow pumps, blowers and compressors – A review
M Sreekanth, R Sivakumar, M Sai Santosh Pavan Kumar, K Karunamurthy, MB Shyam Kumar, R Harish
Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy, 2021
Yaw Moment Compensation by Actuator-Based Control of Brake System in Automobiles
Vaibhav Bisht, D Saravanakumar, G Sakthivel, R Sivakumar
Journal of Physics Conference Series, 2021
Effect of hydrogen jets in supersonic mixing using strut injection schemes
S. Jeyakumar, Jayaraman Kandasamy, Mehmet Karaca, K. Karthik, R. Sivakumar
International Journal of Hydrogen Energy, 2021
Effects of nanoparticle dispersion on turbulent mixed convection ows in cubical enclosure considering Brownian motion and thermophoresis
R. Harish, R. Sivakumar
Powder Technology, 2021
Turbulent thermal convection of nanofluids in cubical enclosure using two-phase mixture model
R. Harish, R. Sivakumar
International Journal of Mechanical Sciences, 2021
Intelligent obstacle avoiding AGV using vector field histogram and supervisory control
S. S. Bolbhat, A. S. Bhosale, G. Sakthivel, D. Saravanakumar, R. Sivakumar, J Lakshmipathi
Journal of Physics Conference Series, 2021
Numerical investigations on the hydrogen jet pressure variations in a strut based scramjet combustor
Jeyakumar Suppandipillai, Jayaraman Kandasamy, R. Sivakumar, Mehmet Karaca, Karthik K.
Aircraft Engineering and Aerospace Technology, 2021
DOE study of ‘the effect of various parameters on fuel tank sloshing using multiphase CFD’
Supriya J. Magdum, Alokekumar Das, Vinayak Shetty, R. Sivakumar, G. Sakthivel
International Journal of Ambient Energy, 2021
Condition monitoring of carbide and non-carbide coated tool insert using decision tree and random tree A statistical learning
K.A. Ajayram, R. Jegadeeshwaran, G. Sakthivel, R. Sivakumar, A.D. Patange
Materials Today Proceedings, 2021
Combustion Characteristics of Nanoaluminium-Based Composite Solid Propellants: An Overview
Kandasamy Jayaraman, Ponnurengam Malliappan Sivakumar, Ali Zarrabi, R. Sivakumar, S. Jeyakumar
Journal of Chemistry, 2021
Comparison of Dynamic control model of Autonomous Underwater Vehicle Guidance
S. Manoj Srivatsn, G. Sakthivel, D. Saravanakumar, R. Jagadeeshwaran, R. Sivakumar
Proceedings 2020 6th IEEE International Symposium on Smart Electronic Systems Ises 2020, 2020
Emission Characteristic of a Dual fuel Compression Ignition Engine Operating on Diesel + Hydrogen & Diesel + HHO gas with same Energy Share at Idling Condition
Balaji Subramanian, T Venugopal, M Feroskhan, R Sivakumar
Iop Conference Series Earth and Environmental Science, 2020
Market response of real estate and automotive industry during pandemic-a transdisciplinary approach
International Journal of Management, 2020
Condition monitoring of hydraulic brake system using rough set theory and FUZZY rough nearest neighbor learning algorithms
Alamelu Manghai T M, Jegadeeshwaran R, Sakthivel G, Sivakumar R, Saravana Kumar D
Proceedings 2019 IEEE International Symposium on Smart Electronic Systems Ises 2019, 2019
Vibration based IC engine fault diagnosis using tree family classifiers-a machine learning approach
Naveen Kumar P, Sakthivel G, Jegadeeshwaran R, Sivakumar R, Saravana Kumar D
Proceedings 2019 IEEE International Symposium on Smart Electronic Systems Ises 2019, 2019
Design and analysis to analyse the heat transfer of a space heater for a boat
B. I. Darshandeep, R. Sivakumar, G. Sakthivel, S. Subramaniam, Jussi Oksanen
International Journal of Ambient Energy, 2018
A decision support system to evaluate the optimum fuel blend in an IC engine to enhance the energy efficiency and energy management
G. Sakthivel, R. Sivakumar, N. Saravanan, Bernard W. Ikua
Energy, 2017
Selection of optimum fish oil fuel blend to reduce the greenhouse gas emissions in an IC engine—A hybrid multiple criteria decision aid approach
Gnanasekaran Sakthivel, Sivakumar R, Mani Ilangkumaran, Bernard W. Ikua
International Journal of Green Energy, 2016
Thermal analysis of a 3 phase, 550 W Switched reluctance machine
International Journal of Applied Engineering Research, 2015
Thermodynamic analysis of different cycles for high-temperature concentrated solar power applications
Rajesh Mavuri, Kosamana Bhaskara Rao, R. Sivakumar
Progress in Industrial Ecology, 2015
Flexible charging time and geography independent dual thermal cycle based energy storage
Kosamana Bhaskara Rao, Rajesh Mavuri, R. Sivakumar
Progress in Industrial Ecology, 2015
CFD analysis of micro-ramps for hypersonic flows
Ashish Mogrekar, Ramasami Sivakumar
Applied Mechanics and Materials, 2014

SIVAKUMAR RAMASAMI

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