http://dspace.dtu.ac.in:8080/jspui/handle/123456789/220 2026-04-28T04:03:35Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/20193 Title: STUDY OF GAS TURBINE COGENERATION CYCLE WITH INLET EVAPORATIVE COOLING AND REHEATING Authors: RAUTELA, JYOTI Abstract: Energy has been a major concern over the years all over the world. Cogeneration is being coined as the efficient utilization of energy in various power plants. Gas turbine being the compact and one of the most reliable means for the generation of power is pretty good to be used for cogeneration. Cogeneration in general is a term used for producing heat and work simultaneously. The exhaust heat from the turbine is used as the process steam for either district heating, cooling at various applications. Cogeneration with gas turbines is the frequently and widely used cogeneration system because this type of system takes the advantage of the relative merit of engine and enhances thermal efficiency at full load conditions as well as part load conditions. Also, it is highly accepted in power industries. The work performed provides a review of research investigation on cogeneration systems which are carried out during the last few years. Along with the literature review, the performance of various output parameters of gas turbine cogeneration system with reheat and inlet evaporative cooling (proposed cycle) are analyzed parametrically taking compressor pressure ratio, turbine inlet temperature, pinch point temperature and inlet temperature of air as the main variables. The effect of these parameters on power/specific work, efficiency, power to heat ratio, First law efficiency and second law efficiency were plotted with the help of EES software. 2020-08-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/19750 Title: COMPARATIVE ENERGY AND EXERRGY ANALYSIS OF ORC-VCR AND MODIFIED ORC-VCR CYCLE USING DIFFERENT WORKING FLUIDS Authors: SUKHDAVE, AKITA Abstract: This study examines the energy and exergy of a solar-powered Organic Rankine Cycle (ORC) that uses the refrigerants R245fa, R602, and R600 as working fluid to generate electricity. The suggested cycle combines a solar-sub system with a heliostat and a central receiver with an ORC. The rate of exergy destruction (irreversibility) in each component of the ORC cycle is calculated to assess the cycle's actual performance as well as the causes and locations of thermodynamic imperfection. Using the first and second law technique, parametrical analysis is used to determine the influence of different operational factors on the performance of the ORC Cycle. The impact of several operating factors including turbine input pressure, turbine back pressure, and condenser temperature on energy and exergy efficiency, as well as irreversibility in ORC components such the heat recovery vapour generator, turbine, condenser, and pump, was investigated. Energy efficiency rises from 9.74 percent to 11.3 percent and exergetic efficiency increases from 10.43 percent to 12.10 percent with an increase in turbine intake pressure (1.58-2.38 MPa). The energy and exergy efficiency drops from 11.62 percent to 9.80 percent and 12.44 percent to 10.44 percent with an increase in turbine back pressure (0.18-0.26 MPa). Using R600, R602, and R245fa, the suggested solar-powered ORC cycle will be beneficial for power generation. 2021-08-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/19735 Title: NUMERICAL SIMULATION OF SINGLE AND DOUBLE SLOPE SOLAR STILL FOR DIFFERENT VARIABLES Authors: KUMAR, ROHIT Abstract: Water and the use of conventional energy sources are two significant problems in the world. Water is essential for sustenance. Human beings need of potable water at less consumption of non- renewable energy resources. There are many techniques to convert saline water into potable water. In this paper, three-phase, three dimensional a single slope and double slope single basin still both were prepared and simulated by using ANSYS FLUENT v19.2. Simulation results of solar stills were made by using evaporation as well as condensation process at the climate conditions of Delhi (27.0238° N, 74.2179° E). Within the scope of this study, simulation results of both systems were calculated and compared with each other. It is examined that the temperature inside the single slope solar still is maximum from 13:00 to 14:00 hrs while the double slope still has low temperature compared to the single still. The maximum and minimum temperature of the water-vapor mixture inside the single slope still were calculated 435.39K and 22.283K and the maximum and minimum temperature on glass were 379 K and 16.22 K whereas in double slope, the maximum and minimum temperature of the water-vapor mixture inside the still were 92.12K and 25.60K and glass temperature were 76.154K and 19.22K. Hence, due to the temperature difference between the glass surface and outer environment, more condensation will be in the single slope solar still. Inner water temperature is responsible for more evaporation and higher temperature more than 50℃ can be found in single slope solar still as compared to the double slope. The maximum water production rate in single slope solar still is 0.84 kg m-2 hr-1 while the maximum water production rate in the double slope is 0.26 kg m-2 hr-1 . In the simulation, all other variables are also checked and calculated, also observed single slope solar still has a high value of all variables which affect water production. Hence, the single slope solar still could be better there. 2020-08-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/19627 Title: SOME STUDIES ON ENGINE COMBUSTION, EMISSION, AND SPRAY CHARACTERISTICS OF A CRDI DIESEL ENGINE WITH VARIABLE NOZZLE GEOMETRY USING ANSYS Authors: SINGH, VAIBHAV SINGH Abstract: The present study aims to investigate the effect on combustion, emission, and spray characteristics with the variation of the nozzle hole diameters (NHD) in a diesel engine. For this a CFD 3D model is developed for a four stroke diesel engine fueled with neat diesel and three different NHD, i.e., 0.20 mm, 0.26 mm, and, 0.30 mm. The CFD 3D models were effectively able to predict the turbulence and turbulent-flame propagation interaction, chemistry involved in combustion processes, and the dissociation and reassociation of chemical species. For the model validation, the combustion characteristics of the CRDI-VCR engine are used. The validation results showed good compatibility having the relative error within the range. The analysis showed that increasing the nozzle hole diameter resulted in the decrease of the in-cylinder pressure by about 8.31% and 31.93%, respectively, for 0.26 mm and 0.30 mm diameter compared to 0.20 mm. The AHRR also showed a similar trend with a decrease of about 11.82% and 42.18%, respectively, for 0.26 mm and 0.30 mm diameter as compared to 0.20 mm. Subsequently, the increase in nozzle diameter showed an increase in HC and CO emissions but a decrease in NOx emissions. The CO emissions increase by about 0.65% and 5.08% and HC emissions increase by about 29.90% and 60.13% respectively for 0.26 mm and 0.30 mm diameter compared to 0.20 mm. viii While the NOx emission reduces by about 41.18% and 70.58% respectively for 0.26 mm and 0.30 mm diameter as compared to 0.20 mm. The effect of different nozzle diameters on spray characteristics is analyzed and verified from previous studies. The increase in nozzle diameter showed an increase in liquid penetration length, breakup length, and SMD. Also, the present study shows the possibilities of the CFD models for the simulation of engines employing different fuels and operative conditions. 2021-10-01T00:00:00Z