Faculty Publications
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Publications by NITK Faculty
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Item Design optimization of a highly sensitive spiral photonic crystal fiber for liquid and chemical sensing applications(Academic Press Inc. apjcs@harcourt.com, 2019) Malavika, R.; Krishnan, P.In this paper, a spiral shaped photonic crystal fiber (PCF)is proposed for liquid sensing applications. The guiding properties of the proposed PCF are analysed. Sensitivity coefficient is analysed by varying different structural parameters for a wider wavelength range. In addition, confinement loss is also studied at the same wavelengths. The relative sensitivity achieved for the optimized parameters are 56.8%, 58.3% and 62.7% for water (n = 1.33), propane (n = 1.34)and propylene (n = 1.36)respectively. With its low confinement loss and high sensitivity the proposed PCF can be used for liquid and chemical sensing applications. © 2019 Elsevier Inc.Item Fuzzy uncertainty and its applications in reinforced concrete structures(Emerald Group Holdings Ltd., 2020) Worabo Woju, U.W.; Balu, A.S.Purpose: The aim of this paper is mainly to handle the fuzzy uncertainties present in structures appropriately. In general, uncertainties of variables are classified as aleatory and epistemic. The different sources of uncertainties in reinforced concrete structures include the randomness, mathematical models, physical models, environmental factors and gross errors. The effects of imprecise data in reinforced concrete structures are studied here by using fuzzy concepts. The aim of this paper is mainly to handle the uncertainties of variables with unclear boundaries. Design/methodology/approach: To achieve the intended objective, the reinforced concrete beam subjected to flexure and shear was designed as per Euro Code (EC2). Then, different design parameters such as corrosion parameters, material properties and empirical expressions of time-dependent material properties were identified through a thorough literature review. Findings: The fuzziness of variables was identified, and their membership functions were generated by using the heuristic method and drawn by MATLAB R2018a software. In addition to the identification of fuzziness of variables, the study further extended to design optimization of reinforced concrete structure by using fuzzy relation and fuzzy composition. Originality/value: In the design codes of the concrete structure, the concrete grades such as C16/20, C20/25, C25/30, C30/37 and so on are provided and being adopted for design in which the intermediate grades are not considered, but using fuzzy concepts the intermediate grades of concrete can be recognized by their respective degree of membership. In the design of reinforced concrete structure using fuzzy relation and composition methods, the optimum design is considered when the degree of membership tends to unity. In addition to design optimization, the level of structural performance evaluation can also be carried out by using fuzzy concepts. © 2020, Emerald Publishing Limited.Item Combustion modelling of sequential combustion in steam-methane reformation (SMR) furnace using adiabatic flamelet generated manifold(Elsevier Ltd, 2023) Joe, E.S.; Arumuga Perumal, D.A.Hydrogen as an energy vector of the future is being explored by many. Steam-methane reformation proves itself as a major source of hydrogen that is to play a major role in the electrification of the energy sector and decarbonization efforts. Detailed design and design optimization of SMR furnaces are required to maximize the production within a plant. Unit-operation level process of a cogeneration plant, producing both energy and hydrogen, have been studied by other researchers. Sequential combustion of natural gas/methane within the furnace of an SMR unit placed downstream of a power generating gas turbine is analysed within the present work using computational fluid dynamics. Flamelet generated manifolds as a means of combustion modelling for a large-eddy simulation is used to analyse the flow features, flame structure and the vortex-flame interaction. The fuel rich case features a stable flame although with a lower temperature, and the fuel lean case features an unstable flame. The outcomes of this study may be utilized by designers to study factors that bottle-neck production in the furnace. © 2023 Elsevier LtdItem Driving Cycle-Based Design Optimization and Experimental Verification of a Switched Reluctance Motor for an E-Rickshaw(Institute of Electrical and Electronics Engineers Inc., 2024) Bhaktha, B.S.; Jose, N.; Vamshik, M.; Pitchaimani, J.; Gangadharan, K.V.This article deals with the design and optimization of a 2 kW switched reluctance motor (SRM) for an electric rickshaw (E-rickshaw). Previously published research on SRM optimization has mostly focused on the optimization of their design and control variables only at the rated conditions. In electric vehicle (EV) applications, the load operating points (LOPs) of a traction motor are dynamic and spread widely across the torque speed envelope. To enhance their overall performance, it is vital to include them in the design optimization process; therefore, in this article, a novel procedure for implementing the multiobjective design optimization (MODO) of an SRM based on a driving cycle has been demonstrated. Higher starting torque and torque density with reduced electromagnetic losses throughout the driving cycle are established as the design objectives, subject to practical restrictions on current density and slot fill factor. The design objectives have been accurately evaluated through transient finite element analysis (FEA) and a computationally efficient SRM drive model (developed in MATLAB/Simulink) with consideration of the excitation control parameters. Kriging models have been constructed to reduce the computation cost of FEA during the optimization process. Then, a nondominated sorting genetic algorithm II (NSGA II) based multiobjective optimization coupled with the constructed Kriging models is conducted to generate a Pareto front. An optimal design that offers the best balance between the design objectives is selected from the Pareto-optimal set, and the dimensions of corresponding design variables are used to build a prototype. Finally, the static and dynamic performance of the SRM prototype are experimentally evaluated and validated with the FEA simulations. © 2024 IEEE.Item Driving cycle-centric design optimization and experimental validation of high torque density outer rotor 8/18 MTSRM for an E-Bike(Elsevier Ltd, 2025) B, S.B.; Sarma, S.; Vamshik, M.; Pitchaimani, J.; Bhaktha, K.V.This paper presents an innovative methodology for optimizing the design parameters of a 500 W low-speed outer rotor switched reluctance motor (OR-SRM) for an electric bicycle (E-bike) in accordance with a driving cycle. Design optimization of SRMs based on driving cycles has been minimally explored in the literature, with all existing research focusing exclusively on high-speed electric vehicle (EV) applications. These studies utilized computationally intensive dynamic current analysis methods to account for the significant dynamic effects incurred. Given the E-bike's low-speed characteristics, the present study mitigates the computational load of design optimization through static current analysis. A high torque density 8/18 OR-multi-teeth (MT) SRM topology has been proposed. The benefits of this topology, such as mass, cost, torque ripple reductions, and improved torque density, have been highlighted through a comparison with a conventional 6/10 OR-SRM topology. The reliability of the finite element analysis models used in this study is validated through experiments conducted on an 8/18 OR-MTSRM prototype. The multi-objective design optimization aims to maximize starting torque and minimize torque ripple and electromagnetic losses throughout the driving cycle. The efficacy of the optimization is confirmed by the enhancement in the performance parameters of the optimal design compared to the preliminary design. © 2025 Elsevier Ltd