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Author: search.filters.author.Srinivasan, P.Subject: search.filters.subject.Mechanical Engineering

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    Theoretical Analysis of a Self-Condensing CO2 Transcritical Power Cycle With Regeneration Involving Dense Particle Suspensions in a Solar Thermal Power Plant
    (ASME, 2022-10) Srinivasan, P.
    The choice of heat transfer fluids (HTFs) significantly dictates the thermal efficiency of the solar power plant. Presently, molten salt is widely used choice owing to its phase, low cost, and non-toxic nature. Along with other alternatives like liquid metals and multiphase fluids, these HTFs are limited to peak operating temperatures ranging from 300 to 550 °C. With the introduction of dense particle suspensions as an HTF, the highest operating temperatures in a solar thermal power plant can reach up to 700 °C, offering considerable scope for improving thermal efficiency. Due to the higher average specific heat as compared to the alternatives, CO2 is a promising working fluid in the considered range of moderately high operating temperatures. The cost of the components and size of the power block make the transcritical CO2 cycle an attractive alternative. The present work analyzes the theoretical efficiency of the proposed cycle, with the peak operating temperature ranging from 550 °C to 700 °C. The effects of the variation in the lower operating pressure and the condensation temperature have also been analyzed. It is observed that thermodynamic efficiencies as high as 40% can be reached at the maximum operating temperature. The optimum combination of the lower operating pressure and the condensation temperature is also noted.
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    Compatibility of structural materials with AlSi12 alloys-based phase change material and increasing the corrosion resistance by ceramic coatings
    (Elsevier, 2023-11) Srinivasan, P.
    Aluminum Silicon eutectic (AlSi12) alloy-based latent heat thermal energy storage can be integrated with concentrated solar power (CSP) to generate dispatchable power at an affordable cost. Despite AlSi12's favorable thermophysical properties, it reacts with steel at higher temperatures, posing a challenge for storage containers (structural materials). The use of ceramic materials as a protective coating for steel is possible due to their corrosion-resistant properties. Thus, this study examines the compatibility of steel structural materials (SS316, SS202, and P91) and ceramic-coated steel (Alumina – Al2O3 and Yttria Stabilized Zirconia – YSZ) with molten AlSi12. The experiment indicates that P91 steel and YSZ-coated steel have better corrosion resistance when measured over 120 h.
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    Tube Failure Analysis and Residual Life Assessment in Water Tube Boiler
    (ASME, 2010) Srinivasan, P.
    This paper presents creep analysis to estimate the remaining life of tubes used in water tube boiler. Three dimensional finite element (FE) models were developed with computer software namely ANSYS Workbench 10.0 to analyze the tube temperature and stress distribution. The FE results showed that the temperature and stress increase as the oxide scale thickness increases. Formulating the creep behavior in terms of well established creep laws, the remaining life of the tube was estimated.
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    Comparing Environmental Impact of Various Energy Sources Powering Data Centres’s at Indian Candidate Locations
    (Springer, 2021-08) Srinivasan, P.
    While major 21st century developments are data-intensive, the use and storage of such high volumes of data are processed through datacentres. Though Datacentres (DC) are typically high-power consumption applications, the percentage of energy consumption is even higher in developing economies such as India. This paper studies the net environmental impact of energy supply to such datacentres, at four candidate locations, by examining their net Green House Gas Emissions per kWh and land usage per kW. The study analyses various sources of energy such as thermal, wind, and solar plus battery systems to provide a comprehensive view of environmental impacts caused by the power supply.
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    CFD Analysis of Air Cooled IC Engine Fins in the Presence of an Obstruction Placed Upstream at Low Ambient Temperatures
    (Begell House, 2021) Srinivasan, P.
    The present work aims to address the issue of overcooling at low ambient temperatures in air-cooled IC engines that use fins for heat transfer augmentation. A design modification is proposed to reduce excess cooling at low temperatures in comparison to the heat flux at room temperature. An arc-shaped obstruction placed upstream to the fin, is used to reduce the heat transfer. Two dimensional computational fluid dynamics analysis using ANSYS Fluent is used to study the effect of the obstruction on the heat transfer coefficient of the fin at various velocity conditions for different geometric parameters of the arc. A relationship between the design parameters of the obstruction arc and the heat transfer coefficient is obtained, from which it is observed that the over-cooling can be significantly reduced at certain design parameters of the arc.
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    CFD Based Study of Gas Turbine Blade Cooling
    (Springer, 2023-03) Srinivasan, P.
    Over the years, many techniques have been employed to improve the aerothermal efficiency of gas turbines. The hot gases inlet temperature greatly affects the work output and therefore, efficiency of the turbine. To overcome the metallurgical constraints associated with maximum blade temperature, different methods have been devised to keep it under the permissible levels. The current thesis explores convective cooling of the blades by the means of internal passages. Other methods like ceramic blades have their own limitations in terms of brittle failure, and thermal barrier coatings are almost always used in conjunction with convective cooling. Conjugate heat transfer (CHT) simulations have been performed on a 65 mm gas turbine blade section with cooling cavity, using ANSYS CFX 2019 FVM solver. Cooling performance and pressure loss characteristics of the cavity have been analysed by increasing number of protrusions on the cavity walls from 0 to 88. The results and plots suggest that an increase in the coolant advection causes a reduction in blade maximum temperature, but the temperature reduction obtained with successive velocity increments follows a diminishing trend. However, the pressure loss associated with the coolant flow follows an increasing trend with increasing slope. Increment in the number of protrusions results in a similar trend, with successive addition of protrusions resulting in greater rise in coolant pressure loss.
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    Three Dimensional Transient Explicit Finite Difference Heat Transfer Modeling of Billet Transport
    (IASKS, 2013) Srinivasan, P.
    In steel industries the billets are heated in reheat furnace. The billets coming out from reheat furnace are transported to the rolling mill. Prediction of billet temperature during transport is vital for several reasons, like energy optimization studies, process simulation, roll force calculation and quality of the final product. Inadequate temperature measuring instruments demands suitable model for billet temperature predictions. In the present work, conduction heat transfer within the billet is modeled using the explicit finite difference method. To solve three dimensional transient discretization equations, code has been developed and implemented in MATLAB ®. Validation of the proposed numerical model has been done using analytical solutions. The model predictions of billet temperature are shown to be in good concurrence with analytical results. The model is capable of predicting temperature distribution within the billet. The model is used to examine the effect of billet transport velocity on the temperature field of the billet. The objective of this work to apply simple simulation technique to high temperature industrial process for temperature field measurements. This type of simulation may be useful for temperature predictions, design and study of new or existing transport system for hot billet transport.
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    Numerical and experimental investigation of melting process in spherical pcm capsule used for low-temperature thermal energy storage systems
    (IOP, 2019) Srinivasan, P.
    The present work deals with the experimental and numerical investigation of melting process of phase change material used for low temperature thermal energy storage applications. Thermal energy storage is a good solution to bridge the gap between energy supply and energy demand. The unconstrained melting of paraffin wax having melting range of 570C to 610C was studied in simple spherical glass capsule. The objective of the subject work is to perform the experimental and numerical analysis of melting process in spherical capsule subjected to constant wall temperature. Ansys Fluent 18 is used for computation purpose. In experimental analysis, melting process was observed through visual capturing of interface between solid and liquid. Melting fraction and temperature at the centre of PCM capsule are monitored both experimentally and numerically. Good consistency in results were observed.
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    Three Dimensional Transient Heat Transfer Model for Steel Billet Heating in Reheat Furnace
    (ASME, 2013-07) Srinivasan, P.
    In steel rolling mills reheat furnaces are used to heat the billets prior to rolling processes. Reheating is one of the most energy intensive processes in the steel industries. Inadequate temperature measuring techniques and extremely complex analytical solution for temperature filed calculations demands suitable numerical model. In the present work a three dimensional transient heat transfer model is developed for billet heating in reheat furnaces. Conduction heat transfer within the billets is modeled using Finite Difference Method (FDM). Fully implicit spatial discretization approximation was used for three dimensional heat diffusion equation of billet. The three dimensional model takes into account the temperature dependent thermo physical properties, reaction heat effect and growing oxide layer. Algorithm is implemented in MATLAB® to solve three dimensional discretization equations. Model is capable of predicting the temperature field for billet and oxide scale thickness for any residence time. The predicted results are in reasonable concurrence with available data. The main objective of this work is to predict billet temperature field and oxide scale thickness for the various residence times, which may be vital for development of energy efficient optimization strategy for reheating process.
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    Steel billet reheat simulation with growth of oxide layer and investigation on zone temperature sensitivity
    (Springer, 2014-03) Srinivasan, P.
    This paper presents a three-dimensional heat conduction numerical model and simulation of steel billet reheating in a reheat furnace. The model considers the growth of oxide scale on the billet surfaces. Control-volume approach and implicit scheme of finite difference method are used to discretize the transient heat conduction equation. The model is validated with analytical results subject to limited conditions. Simulations are carried out for predictions of three-dimensional temperature filed in the billet and oxide scale growth on the billet surfaces. The model predictions are in agreement with expected trends. It was found that the effect of oxide scale on billet heating is considerable. In order to investigate the effect of zone temperatures on the responses, a parametric sensitivity subject to six responses of interest are carried out using analysis of mean approach. The simulation approach and parametric study presented will be useful and applicable to the steel industry.