Browsing by Author "Sinha, Rajendra Prasad."

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    A mathematical model of marine diesel engine speed control system
    (Journal of The Institution of Engineers (India): Series C, 2018-02) Sinha, Rajendra Prasad.; Balaji, Rajoo.
    Diesel engine is inherently an unstable machine and requires a reliable control system to regulate its speed for safe and efficient operation. Also, the diesel engine may operate at fixed or variable speeds depending upon user’s needs and accordingly the speed control system should have essential features to fulfil these requirements. This paper proposes a mathematical model of a marine diesel engine speed control system with droop governing function. The mathematical model includes static and dynamic characteristics of the control loop components. Model of static characteristic of the rotating fly weights speed sensing element provides an insight into the speed droop features of the speed controller. Because of big size and large time delay, the turbo charged diesel engine is represented as a first order system or sometimes even simplified to a pure integrator with constant gain which is considered acceptable in control literature. The proposed model is mathematically less complex and quick to use for preliminary analysis of the diesel engine speed controller performance.
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    Exergy analysis of a medium size LNG tanker steam power plant
    (Annual technical volume, Marine engineering division board, 2016) Sinha, Rajendra Prasad.; Balaji, Rajoo.
    Exergy is the maximum work which can be obtained from a quantity of heat Q at temperature T1 received by a system interfacing with a surrounding environment at temperature T0. In other words from the received heat energy ‘Q’ a small portion fails to convert into useful mechanical work and is thus lost which we call exergy destroyed. The loss of exergy in this heat work exchange process lowers overall thermal efficiency of the plant. Exergy destruction is actually the result of irreversibility in various processes of the plant and can be estimated from the second law of thermodynamics as the product of ambient temperature T0 and the positive entropy change Δsi.e. (T0Δs). The common irreversibility which cause entropy rise are mechanical or hydraulic friction, heat transfer with a finite temperature difference and diffusion with a high gradient of concentration etc., as most of these are present in a physical plant. Exergy analysis gives an insight into the way energy flows in the system and helps to locate components of the plant with high irreversibility to effect design improvements. In this paper the authors conduct energy and exergy analysis of 30 MW dual fuel fired marine steam power plant of a typical medium capacity LNG tanker and identify components responsible for major exergy destruction. Effects of steam reheating to reduce irreversibility and potential utilization of the cold energy of boil off gas in the thermodynamic cycle has been studied with the result showing 2-4 % improvement in the overall exergy efficiency of the plant.