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ThesisItem Open Access Effect of artificially included defect on mechanical and fracture properties of Al 7075-T651 MIG welded butt joint(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Joshi, Shomesh; Gope, P.C.Aluminium 7075-T651 is one of the widely used materials for various applications in industry, aerospace, utensils, etc. In the present investigation, fatigue crack growth on CT specimenand tensile experiments are performed on MIG welded butt joint of aluminium 7075-T651 with artificially included defect of carbon nanoparticles with Pmax= 5 kN, Pmin= 0.5 kN, frequency of 6 Hz and R=.1 under constant amplitude loading and under universal testing machine of 25 kN. The experimental data obtained has been used to plot a-N, da/dN vs. K curve, stress-strain curve and Paris crack growth constants. The fatigue life is found to be 25500,22400,29500 and 27800 cycles respectively for MIG welded CT specimen with single V-notch without defect, single V-notch with defect, double Vnotch without defect and double V-notch with defect respectively for across weld region. But for the along the weld region for the same conditions mentioned above the life came out are 27300, 23500, 31200, 26900, respectively. Also, the ultimate strength is found to be 244.70, 208.31, 274.6, 259.8 MPa for the single V-notch without defect, single V-notch with defect, double V-notch without defect and double V-notch with defect respectively for along weld region. Moreover, for the across the weld region for the same conditions mentioned above, the ultimate strength comes out to be 211.18, 200.12, 242.02, 234.56 MPa, respectively. The values of material constants C and m are calculated through single Paris Curve fit. Mathematical modelling is also done for the above study to find out the trend of the fracture properties and the ultimate strength with respect to the percentage of the defected area in the weld.ThesisItem Open Access Simulation of vapor compression-absorption refrigeration system(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Chauhan, Ritik; Pratihar, A.K.The compression-absorption refrigeration systems has been considered to be the possible replacement of the vapor compression and vapor absorption refrigeration system due to their useful features like better capacity control and its operation at low-pressure levels in the system due to the use of mixtures and higher coefficient of performance compared to vapor compression system. In the present work, thermodynamic analysis of compression-absorption system has been carried out for milk chilling application at 4 ℃. In order to study the performance of system computer simulation of actual system has also been carried out where effect of some important parameters on the coefficient of performance of the system has been studied using Warner’s method. In the simulation of absorber and desorber fourth order Runge-Kutta method has been used. A COP of 4.435 has been obtained at a compression ratio of 4.0, desorber temperature of 8°C, an absorber pressure of 20 bar, maximum concentration of 0.8. It is observed that the exergetic efficiency increases with the decrease in desorber temperature and exergetic efficiency decreases if the value of compression ratio increases. Simulation has been performed for three different lengths of absorber and desorber, 5.0 m, 7.0 m and 10.0 m and three different relative area of solution heat exchangers area, 10%, 20% and 30%. The effect of the mass flow rate of the weak solution, length of absorber and desorber and relative area of solution heat exchanger on the COP, cooling capacity and absorber heat load has been studied. The results show that the COP of the system can be increased by maintaining a low mass flow rate of the weak solution, large relative area of solution heat exchanger and a large absorber and desorber length. From simulation it is found that COP of the system attains a maximum value at a given mass flow rate of weak solution. By increasing the length of absorber and desorber from 5 m to 10 m, the COP of the system increases from 2.96 to 3.25 i.e. an increase of 9% is attained.ThesisItem Open Access Performance comparison of solar cooker using different phase change materials during off sunshine hours(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Abhishek Kumar; Bhandari, Susheel SinghThe continuous increase in the level of greenhouse gas emissions and the increase in fuel prices are the main driving forces behind efforts to more effectively utilize various sources of renewable energy. In many parts of the world, direct solar radiation is considered to be one of the most prospective sources of energy. Energy requirement for cooking accounts for 36% of total primary energy consumption in India. Hence, there is a critical need for the development of alternative, appropriate, affordable mode of cooking for use in developing countries. However, the large scale utilization of this form of energy is possible only if the effective technology for its storage can be developed with acceptable capital and running costs. Solar cooker is the best way to utilize solar energy. In the present work thermal performance of a box type solar cooker has been evaluated according to the bureau of Indian standard (BIS). The BIS suggested two test for evaluation of thermal performance. The first test is stagnation test for evaluation of first figure of merit F1.The second test is full load test for the determination of second figure of merit F2. The first figure of merit is obtained by conducting the stagnation temperature test without load for empty box type solar cooker. The first figure of merit is the ratio of optical efficiency to heat loss factor. The second figure of merit is obtained by sensibly heating a known amount of water and it is a measure of heat exchange efficiency factor of a box type solar cooker. The variation in second figure of merit is also studied by increasing load and number of pots. It is found from experimental study that second figure of merit increases with load and number of pots. The value of figure of merit imply that the cookers are identical and satisfy BIS standard. The performance comparison of solar cooker using different phase change materials during off sunshine hours is main emphasis of the present experimental study. Cookers are also studied using modified finned cooking vessel. Three different phase change materials paraffin wax, stearic acid, lauric acid are selected. It is found from experimental studies that finned cooking vessel increases efficiency and reduces the cooking time. Paraffin wax is best phase change material to store latent thermal energy during sunshine hours and to retrieve back its conserve energy to thermic fluid water during off sunshine hours.ThesisItem Open Access Experimental studies on a double slope single basin solar still using sensible heat storage materials(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Negi, Pankaj; Varshney, LokeshMany countries are facing a shortage of potable water, as the population is increasing rapidly. Most of the water present on earth’s surface is in oceans and lakes which is either saline or brackish water. This water can solve water-related issues by converting it into potable water through desalination process. Many people are suffering from water-borne diseases by consuming contaminated water, therefore there is an essential requirement of potable water production technology for its distillation. Solar energy is cheap and easily available and can be utilized for converting saline water into potable water. Solar still is a device which uses solar energy to convert saline water into distilled. Productivity of conventional solar still is found to be low. Attempts have been made by researchers to improve the productivity of solar still. Present work is an attempt to increase the productivity of double slope single basin solar still by utilizing sand bed as sensible heat storage material beneath the basin of solar still. Experiments have been conducted for sand bed of thickness 0.5 and 1.0 cm and furthermore for mixing engine oil (SAE 20W40) with the sand bed of thickness 0.5 cm up to saturation limit for filling voids and minimizing contact resistance for heat transfer between basin and storage bed. Intermittent glass cover cooling has also been done for reducing the temperature of the glass cover and increasing the amount of condensate. Results of experiments revealed that daily productivity of solar still is increased by utilizing sand bed beneath the basin of solar still. Daily productivity of still increased by 10.72% and 3.16 % by utilizing 0.5 and 1.0 cm thick sand bed respectively for basin water depth 0.6 cm. There is an increment of 11.16 % in daily productivity of modified still with a 0.5 cm thick sand bed by intermittent glass cover cooling. Daily productivity of solar still modified with 0.5 cm thick sand bed increases by 6.16 % by mixing engine oil in the sand bed.ThesisItem Open Access Thermodynamic analysis of organic rankine cycle with zeotropic working fluid for waste heat recovery(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-01) Joshi, Vipul; Tewari, P.C.Organic Rankine Cycle (ORC) is an efficient and practical way for extracting energy from low-grade energy sources such as solar energy, geothermal energy, waste heat from plants and IC engines etc. Many recent researches in this area have focused on increasing the efficiency of cycle and reducing the waste of available energy. In present work, a thermodynamic analysis of an Organic Rankine Cycle working on zeotropic fluids is done. The heat source for the cycle are exhaust gases of a marine, two-stroke CI engine. Two different fluid mixtures, Butane/Cyclopentane (0.2/0.8) and R123/Benzene (0.3/0.7), are considered in the ORC setup, both with and without internal heat exchanger. Later, performance of the engine also has been analyzed for different loading conditions on engine, with ORC working as a bottoming cycle. Thermodynamic analysis includes both the energy and exergy analysis of the cycle on parameters such as thermal efficiency, total work obtained using ORC, exergy efficiency and rate of irreversibility. Maximum thermal efficiencies of 16.60% and 16.20% are obtained using Butane/Cyclopentane and R123/Benzene, respectively. In addition, maximum exergy efficiency of 42.68% is obtained using Butane/Cyclopentane, whereas the same is 41.96% when R123/Benzene is used as working fluid. It is also observed that using an internal heat exchanger is thermally efficient in present cycle setup. Using heat exchanger, an increase of 11.27% and 11.04% in maximum engine power is calculated using Butane/Cyclopentane and R123/Benzene working fluids, respectively. The accuracy of the mathematical model is demonstrated by comparing the obtained thermal parameters with the previous results of G. Shu et al. (2014).ThesisItem Open Access Mechanical and thermal characterization of ceramic thermoset composite(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Mohd. Sajid; Sah, P.L.In the present thesis work experimental investigation has been carried out to study the effect of mortar particles on mechanical and electrical properties. In this mortar particles at different wt% (0, 24, and 100) have been filled in epoxy resin and the effects of mortar particles on mechanical and thermal properties has been studied. Tests have been conducted on 100 kN servo-hydraulic universal testing machine under displacement mode of control and impact testing machine were used for mechanical testing and electrical conductivity have been studied by using Four Point Probe Conductivity Measuring system. Mechanical test results indicate that the mechanical property of the composite, compression strength with the variation in mortar particle first increases and then decreases. Nevertheless, the tensile strength and impact strength of the composite are decreased as the wt% of mortar particles increased. Electrical conductivity results indicate that it first get increases and then gets decrease as the wt% of mortar particles increased. On the basis of overall study the epoxy filling of 24 wt% of mortar particles is found to be better than other combinations.ThesisItem Open Access Experimental studies on double slope single basin solar still using absorbing materials(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Joshi, Ketan; Varshney, LokeshRequirement of water is rapidly increasing due to increase in population and per capita increase in consumption rate of water in both industrial and domestic sector. This increased water demand leads to scarcity of water. Water bodies like rivers, lake, pond, well etc. have saline or brackish water that increases the problem to meet the increasing demand of potable water. By consumption of impure water many people suffer from waterborne diseases like cholera and jaundice. Thus need of the hour is to increase resources to supply fresh water. Several desalination techniques are employed in the past for desalination of saline or brackish water. Solar energy is a cheap and easiest way that can be used to obtain fresh water from the brackish or salty water to make it worth drinking and other purposes using solar stills. Solar still has many advantages over other desalination techniques. Operation of solar still is simple, cheap and requires less maintenance. The basic problem with solar still is its less productivity. Many attempts have been made to improve the efficiency of the solar still. Free surface area of water, water and glass cover temperature difference, absorber plate area temperature of inlet water, glass angle and depth of water are the various operating parameters, which affects the productivity of the solar still. Present research work is an approach to maximize the production rate by using absorbing materials (washed stones, black ink, jute cloth and cow dung cake) in such a manner that the area exposed to sunlight increases and storage of sensible heat during sunshine hours could be possible for production of clean water during off sunshine hours. Intermittent glass cover cooling is also provided as a modification in conventional solar still. Experiments are conducted for both combinations absorbing materials in the basin with no glass cover cooling and absorbing material in basin with intermittent glass cover cooling. Experiments are performed for different water depths (0.7 cm, 1 cm and 2 cm) in basin of the double slope single basin solar still. It is found that lower the water depth higher is production per day of fresh water. Results of the experiments revealed that due to placing the different absorbing materials in the basin and by intermittent cover cooling there is improvement in daily production rate. For washed stones in basin without intermittent cover cooling highest production is for 0.7 cm basin water depth having value of 4.012 L/m2 which is 12.07% more than that of conventional solar still. Water depth of 0.7 cm in basin and with intermittent cover cooling from outside of the glass cover produces 4.829 L/m2 potable water and conventional solar still produces 3.57 L/m2 potable water per day which is 35% more than that of conventional solar still. With washed stones and cover cooling the production rate of modified solar still is increased by 33% and 30% for 1 cm and 2 cm water depth, respectively as compared to that of conventional solar still under similar condition. For black ink in basin water, 0.7 cm water depth with glass cover cooling give best results among 0.7 cm, 1 cm and 2 cm water depths. Production of 4.794 L/m2 potable water per day with 0.7 cm water depth and glass cover cooling is received. For jute cloth dipped in basin water overall production observed is 4.7 L/m2. The production is for arrangement of 1 cm water depth with intermittent glass cover cooling. Overall production per day increased by 34% in modified solar still as compared to that of conventional solar still. For cow dung cake with water depth of 1 cm and 2 cm in basin production increased by 17% and 18%, respectively as compared to that of conventional solar still.ThesisItem Open Access Modeling and failure analysis of hybrid laminated composite structures(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Singh, Sujeet Kumar; Saxena, RakeshLaminated composites are widely used in engineering and structural applications due to their high directional stiffness and strength. In present work a parametric study of hybrid laminated composite structures has been performed. There are two types of lamina glass-epoxy and graphite-epoxy are taken for this investigation. The investigations have been conducted with parameter stacking sequence, ply orientation, number of lamina and boundary conditions. The stiffness and failure indices of different hybrid lamina have been computed. The results of Ansys were first validated with experimental results. Various failure theories i.e. maximum stress theory, maximum Tsai-Wu, failure criteria are implemented for failure analysis. First ply failure strength for different lamination schemes have been calculated under transverse loading conditions.ThesisItem Open Access CFD simulation of forced convective cooling in microelectronics(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-08) Uniyal, Babli; Murthy, D.S.Thermal challenges in microelectronics is perpetually increasing, so various techniques are available in the industry to reduce the thermal challenges, out of which cooling fin arrangements are one of the best technique which is used in the present study. Different models of fins, (such as inline rectangular fin, inline aerodynamic fin, inline inlet rounded fin, inline inlet outlet rounded fin, staggered rectangular fin and staggered inlet rounded fin) placed in a horizontal channel of previous work are simulated for validation of model and modified geometries are proposed (such as staggered inlet outlet rounded fin, staggered triangular fin, staggered parabolic, and double staggered rectangular fin). SIMPLE algorithm is used for pressure velocity coupling and second order upwind scheme is used for discretization of governing equation. Effect of Reynolds number varying from 151 to 1170 on the heat transfer rate, pressure drop, power input and quality factor is investigated for different fin arrangements. From the simulation, it has been found that double staggered fin performs better than other models. For double staggered fin the investigation is carried out for different gaps maintained between two staggered fins i.e. 0.583, 1.166, 1.749, 2.332 and 2.915mm. A gap of 1.749mm for double staggered fin gives the best quality factor than other models which is 46.15% higher as compared to staggered rectangular fin. Performance of various fin geometries is also presented in the thesis.