Research Publications

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    Control strategy for fuel saving in asynchronous generator driven electric tugboats
    (IEEE, 2016-12) Anil Kumar, B.; Anil Kumar, K.; Radha, T.; Chelliah, Thanga Raj; Khare, Deepak; Ramesh, U. S.
    Usually electric tugboats are equipped with diesel engine based electric generator for power production, battery for supplying power to auxiliary loads and electric motors for propulsion. This paper proposes control strategies for diesel engine and electric generators used in electric tugboat to improve energy efficiency of the system. Doubly fed induction machine (DFIM), asynchronous in nature, is considered in this research which serves as generator (power production). The speed of diesel engine is controlled in accordance with the power demanded by the tug. Output voltage and frequency of generator during sub-synchronous operation are regulated by controlling its rotor current with the help of power electronic convertors. Comparison of fuel consumption at fixed and variable speeds of operation is performed. From the test results, it is observed that the variable speed operation of diesel generator offers significant reduction in fuel consumption.
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    Theoretical ship wave pattern resistance evaluation using Kochin wave amplitude function
    (International Journal of Innovation Research & Development, 2012-12) Chavali, Revathi; Kareem Khan
    Ship wave pattern resistance evaluation has been an important event in the optimization process of variety of hull forms ranging from small crafts to fast displacement hull forms including multihull vessels. Several experimental methods for wave pattern analysis like Hogben Matrix Element Method (MEM), Longitudinal & transverse wave cuts involving Landweber Fourier Transform (LFT) and Matrix solution method, theoretical methods like Michell's thin ship theory, Rankine sourcesink and Kochin-Fourier method exist today with their merits and limitations. Ship wave pattern resistance is mostly a derived quantity from experiments either as a subset of residuary resistance or when total viscous component is known. In general applying Froude's hypothesis, the residuary resistance coefficient is not subjected to scaling effects from model to prototype and evaluation of total viscous component for surface ships by model experiments is seldom done. Optimization of hull forms through wave pattern studies is a powerful tool and in-house potential flow solvers/experimental evaluation techniques for free surface flows have been developed in many hydrodynamic test facilities. The present paper focuses on ship wave pattern evaluation using Michell's theory (using Kochin wave amplitude function) and its comparison with Shipflow® & Longitudinal wave cut method (using LFT) on bench mark test model R/V Athena. Matlab® code development and ship wave pattern resistance evaluation sensitivity for the method chosen is also a part of present discussion.
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    Design verification of heat exchanger for ballast water treatment
    (Jurnal Teknologi, 2014) Balaji, Rajoo.; Yaakob, Omar.; Adnan, Faizul Amri bin.; Koh, Kho King.
    Using waste heat from ship’s engines is one of the methods considered for heat treatment of ballast water. For such a system harvesting the engine exhaust heat, a heat exchanger will be vital. Design optimisation of a heater employing exhaust gases of the engine as utility fluid and ballast sea water as the process fluid was achieved using Lagrangian methods, keeping the annual cost as the objective function. Costs for installation, maintenance as also costs for the utility and process fluids were considered. Heat balance data, specific fuel consumption values from a typical operational ship and current fuel costs were considered for the design. The thermodynamic and geometric designs were worked out using computer based software for comparing the designs. Costs were also computed using a different approach for all the designs. Since the amount of heat transferred was specified and the application was limited to a single process, direct cost method was used for the computation. The objective function values obtained from Lagrangian equations were compared with the values obtained from direct cost computations. From the optimal designs, choice was justified based on annual cost, optimum exit temperature of shell side fluid and optimum mass flow of tube side fluid.
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    Improved fuel-use efficiency in diesel–electric tugboats with an asynchronous power generating unit
    (IEEE Transactions On Transportation Electrification, 2019) Anil Kumar, Birudula; Raghu, Selvaraj; Thanga Raj, Chelliah; Ramesh, U. S.
    High capacity diesel–electric tugboats are employed at every modernized harbor for assisting big marine vessels and other harbor applications. Contemporary tugboats use multiple power sources to meet their propulsion and auxiliary on-board load demands. The effective utilization of multiple power sources leads to better fuel use efficiency with reduced emissions, economic, and environmental benefits. This paper presents a simple optimization technique for scheduling available power sources of a diesel–electric tugboat [diesel engine generators (DEGs) and batteries] to meet its load demand with an objective to minimize fuel consumption. For this paper, a diesel–electric tugboat system of 1.1-MW capacity with different generating systems is considered: 1) fixed speed generating unit (2 × 550 kW fixed speed DEG employing synchronous generators) and 2) variable speed generating unit [1×1.1 MWvariable speed DEG employing doubly fed induction generator (DFIG)]. From the optimized test results, it is inferred that the variable speed generating unit offers a fuel saving of 29.86% in comparison with diesel-mechanical propelled system and 2.9%in comparison with fixed speed diesel– electric system. The simulation of a 1.1-MW variable speed generating system is performed in MATLAB/Simulink 2014A environment, and experimental demonstration is performed through a 2.2-kW laboratory prototype
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    Optimization of a hydro kinetic power generator using genetic algorithm
    (Spingerlink, 2021-12-27) Viswanath, Anjana; Chandran, Vidya; Janardhanan, Sheeja
    The paper discusses the optimization of a renewable energy harvester which converts kinetic energy of slow moving currents into electricity. The metaheuristic method of genetic algorithm is adopted to optimize the process parameters of the Hydro Vortex Power Generator (HVPG). The study is conducted in a three folded manner. The device was optimized for the range of Reynolds number 0.3 × 105 < Re < 2.5 × 105 based on equations derived analytically from vibration theory and then using an empirical equation derived from experimental data for two regimes of flow (250 < Re < 3.8 × 104 and 0.3 × 105 < Re < 2.5 × 105. Empirical optimization model is observed to predict the maximum amplitude of oscillation with in a realistic range with the theoretical model showing a three time over prediction. A comparison with experimental results suggests that the effect of added mass on the amplitude of oscillation is of enhanced damping and hence a more realistic prediction is obtained from empirical model optimization. The most significant result from this analysis is that the empirical model predicts maximum amplitude at lowest value of mass ratio (m*), whereas the theoretical model predicts it at the highest value.