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Open Access
Mixed Mode I/II crack growth in dissimilar AA2024-T6 and AA7075-T6 friction stir welded joints
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-12) Tiwari, Saurabh; Gope, P.C.
Aluminium alloy 7075 and 2024 are some of the widely used materials in the aerospace industry. In the present investigation, the effect of SiC nanoparticles on fatigue crack growth and mechanical properties were tested on friction stir welded specimens and compared with as-welded specimens. Fatigue test is performed on different loading angles i.e., 0°, 30°, 45°, 60° and 90° with Pmax= 2 kN, Pmin= 0.2 kN and frequency of 5 Hz with R=0.1 and cracks length is measured using a digital camera fitted on travelling tripod and then compared them with numerically calculated values. All specimens were solution annealed at 460 °C for 2 h and then the ageing heat treatment procedure was done at 170 °C for 16 hours. The experimental data obtained was used to plot stress-strain curve, a-N and da/dN vs. 􀀧Keq curve and various fatigue crack growth parameters such as Paris crack growth constants, crack opening stress intensity factor, etc. were determined. The fatigue life was found to be 37000, 36500, 33000, 30000 and 28000 cycles for friction stir welded CTS specimen at 90°, 60°, 45°, 30° and 0° respectively in as-weld condition. It was observed that there is a significant variation in the variances of crack length increment after the incorporation of SiC nanoparticles. The fatigue life after SiC incorporation was found to be 48200, 39000, 36000, 34500 and 30000 cycles at 90°, 60°, 45°, 30° and 0° respectively. The values of material constants C and m are calculated through a single Paris Curve fit. Scanning electron microscope (SEM) study of fracture surface at different locations was carried out to investigate the different modes of fracture that occurred at different loading conditions and morphology test is used to investigate the grain size distribution at different welding zones.
Open Access
FEA-simulation to optimize laminated composite plate with cutout in free vibrations
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Manuraj; Mishra, Anadi
In the present work, modelling and modal analysis is performed for laminated composite plates. A square plate of 1 meter edge length is studied. There are four boundary conditions considered, which are SSCC, SSCS, SSSS and SSCF. There are four types of standard lay which are considered, Symmetric Ply, Quasi Isotropic Ply, Cross Ply and Angle Ply. The study is performed in three parts as experiments. In the first part the plates are studied for modes which are significant in deformation in the z axis. It is found that 88% of the total modes considered have a very low contribution. The SSCF boundary condition has maximum modes which have higher contribution. In the second part plate with opening is studied. The opening types taken as circular, hexagonal, rectangular and square are studied. It is seen that circular opening is most suitable and square opening is least suitable among these shapes. Large variation occur for the boundary conditions SSCS, SSSS and SSCF and so they must be used after carrying out proper analysis on the basis of application. In the third part direct optimization is carried out for 1st mode frequency as objective function. Elliptical opening with different ratio for major and minor axis length and major axis orientation angle with the reference axis have been taken as parameter for optimization. It is observed that the length ratio of minor to major axis is higher for maximization case than that of minimization case. The orientation angle comes close to 90˚ for SSCF boundary condition. The study is done on the finite element analysis software ANSYS.
Open Access
Development and performance evaluation of a pine needle powder fired cookstove for hilly regions of Uttarakhand
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-01) Upadhyay, Bhawana; Tewari, P.C.
Anything is waste as long as it is utilized. Every year chir pine (Pinus roxburghii) forests in Uttarakhand produces total two millions tonnes of pine needles which is locally called as “Pirul”. These pine needles are highly flammable because of high volatile matter. During summer these pine needles are burned sometime by villagers to clear the floor to allow the growth of green grass for animals and sometimes accidentally these needles catch fire and destroy the forest and releases large amount of greenhouse gasses to the atmosphere. Every year millions of tons of pine needles get burned and turn to ash, cause loss to environment and stop regeneration. Despite being very useful its potential is still untapped among rural people. Still in many villages, most of the energy demand of rural people are being fulfilled by burning the wood in very inefficient way. This is very harmful to the environment and villager’s health. By use of efficient biomass cook-stove the energy demand of the rural people can be fulfilled. Purpose of this research work is to harness the freely available biomass (pine needles). This work concerned with development of powdered fuel stove with improved efficiency and minimal emissions. The design of cookstove originates from a conventional sawdust stove. Water boiling test has been performed for evaluating the thermal efficiency of cookstove and a hood method were used to emission measurement. The thermal efficiency of stove when fired with pine needle powder and sawdust was 25.8 % and 24.4 % respectively. The maximum firepower of the stove with pine needle powder and & sawdust was 2.24 kW, 2.04 kW respectively. The average CO, emission with pine needle powder & sawdust were found 100, 282 PPM respectively. The average HC, emission with pine needle powder & sawdust were found 210, 332 PPM respectively.
Open Access
Exergy analysis of a PVT system having fins in air cooled channel
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-03) Pal, Sumit; Varshney, Lokesh
Photovoltaic thermal (PVT) systems are systems are used to generate electrical energy and remaining energy lost as heat. One of the most critical parameters influencing the performance and life of PV panels is the temperature of photovoltaic (PV) cells. Higher cell temperature increases the waste heat that is not extracted, thus cell voltage/power decreases with an increase in cell temperature. By cooling the solar cell with a fluid stream like air/water/nano fluids, the electricity conversion can be increased. In addition to this, heat energy can be used for other applications such as space heating, drying of agricultural products, paint spraying and related processes. In present work, exergy analysis is done for a solar PVT system having fins in an air-cooled channel attached at the back of the PVT system. For this a 3-D numerical model is developed. Numerical simulations are achieved using ANSYS-Fluent software. The comparative study of air cooled channels with fins and without fins are performed considering two mass flow rates of air of 0.0085 kg/s and 0.0137 kg/s. The parameters such as panel temperature, inlet and outlet air flow temperatures in the air cooling channels are analyzed. Effect of duct depth on the panel temperature, thermal efficiency and exergy efficiency is analyzed. Also, roughness of the duct and fins surfaces on the panel temperature, thermal efficiency and exergy efficiency is analyzed. The results of the PVT system showed considerable improvement in thermal performance with using fin in air cooled channel. The maximum thermal performance observed 8.54 % at a mass flow rate of 0.0085 kg/s and 15.24 % at a mass flow rate of 0.0137 kg/s for the air cooled channel with fins. Subsequently, the maximum exergy efficiency was attained as 3.73 % at a mass flow rate of 0.0085 kg/s and 8.14 % at a mass flow rate of 0.0137 kg/s in air cooled channel with fins. However, the increment in duct depth decreases the thermal efficiency decreased by 0.6 % and exergy efficiency decreased by 0.5%.
Open Access
Comparative study on the melting rate of PCM for circular and semi-circular LHTES system
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Amit Kumar; Verma, Prashant
Latent heat thermal energy storage (LHTES) technique using different types of phase change materials (PCM) has become popular in the last few decades. It helps to reduce the problems related to discrepancy between supply and demand of energy. In the present study, the melting characteristics of a lauric acid in a semi-circular and circular latent heat storage unit has been studied. The low melting rate of PCM in the lower half of a circular heat storage unit can be enhanced by confining the PCM in the upper region by configuring the outer shell of semi-circular cross-section. The recent literature shows that no work has been carried out on the effect of the melting performance of PCM in a semi-circular LHTES unit. So, it has been decided to investigate the melting performance of PCM experimentally and numerically for semi-circular LHTES system. The investigation of the melting performance of PCM in a semi-circular heat storage unit has been done through by developing a numerical 2D model which has been analysed through ANSYS FLUENT. The results obtained from numerical simulation are validated through experimental results. The enhancement in the melting rate at three different inner tube position values (e = 0.20, 0.23 and 0.25) for inner tube from the bottom surface of outer semi-circular shell is investigated and it is found that the enhancement is maximum when the inner tube is nearest to the bottom surface of the outer shell i.e., for e = 0.20. The melting performance of PCM is also studied for different values of inlet temperature of heat transfer fluid for tube position e = 0.20 and it is observed that the increase in Stefan number, enhances the melting rate of PCM in semi-circular LHTES system. The semi-circular heat storage unit is also compared with circular heat storage unit by considering the equal quantity of PCM in both the cases. The semi-circular LHTES system shows enhancement in melting performance of PCM as compared to circular LHTES system. The semi-circular LHTES system melts the PCM completely in almost half time as compared to circular LHTES system. It is found that the thermal energy stored in PCM for semi-circular LHTES system is 416.4 KJ which is 12.04 % more as compared to TES of PCM for circular LHTES for the same time duration of 4800 sec and the thermal energy storage efficiency of semi-circular LHTES unit is 11 % more as compared to the circular LHTES unit.
Open Access
Performance and emission analysis of SI engine using-Ternary fuel blends of Gasoline-Ethanol-Methanol (GEM)
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Singh, Aviral; Gupta, V.K.
Along with the increasing order of population on the earth, the demand for petroleum based fuel is also increasing continuously. Petroleum based reserves are available in limited quantity in the world and these reserves are constantly decreasing with increasing demand day by day, these reserves are continuously decreasing and in future it is being used by humans at high levels, adversely affecting the climate and human health. Research is currently underway to find complete or partial alternatives to petroleum based fuels. Alcohol based fuels such as methanol, ethanol, propanol and butanol are considered good alternative fuels for all vehicles because it has similar properties of gasoline. In the past many researchers have investigated renewable energy and low-emission fuels by mixing different types of alcohol with different percentages of gasoline. In this research we came to know that ethanol is a good alcohol fuel that can be mixed with gasoline. But its excess amount affects or worsens the internal parts of the engine. To avoid this dilemma, we used methanol as an alcohol fuel in equal proportion to ethanol. Due to which we conducted a successful test without modifying the internal parts of the engine while retaining the maximum amount of alcohol. The fuel properties and performance parameter of the engine has been taken such as gross heat of combustion, relative density, BP, BSFC, BTE, BSEC and EGT. Engine emission parameters were also evaluated such as O2, CO2, CO, HC, SO2 and NOX. In this study, renewable energy sources ethanol and methanol were mixed with gasoline and investigated as a new fuel for SI engines. Five mixing ratios were applied (5, 10, 15, 20 and 25%) which are equivalent for ethanol and methanol.
Open Access
Effects of post heat treatment on crack growth behaviour of MIG welded butt joints of dissimilar Aluminum alloys
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Sharma, Saurabh; Gope, P.C.
Aluminium 7075 and 606I-T6 is one of the widely used materials for various applications in industry, aerospace, utensils, etc. In the present investigation, fatigue crack growth experiments were performed on MIG welded butt joint using filler ER 4043 and Silicon Carbide (SiC) nanomaterial reinforced 7075 filler material. The dissimilar material welded by these filler materials were subjected to three post heat treatment conditions such as artificially aged at 150°C for 16 h (HT1), cyclic solution heat treated at 400°C to 480°C for 2 h (HT2) and combination of both HT3 for 16 h and HT2 for 2 h is (HT3). The precracking was done at Pmax = 2kN and R=0.1. The constant amplitude cracks growth tests were conducted using CT specimen at a maximum load of 5 kN and stress ratio R= 0.1. The test frequency was kept 6 Hz. The results obtained from the crack growth tests were analysed intense of a-N curve, da/dN vs (AK) and Paris growth parameters were determined. The effect of post heat treatment as well as different filler materials on the crack growth were discussed. The fatigue life for MIG welded CT specimen using filler ER 4043 and Silicon Carbide (SiC) reinforced 7075 filler rods at as-weld and three heat treatment conditions HT1, HT2 and HT3 was found to be 27500, 24000, 22500, 21500 and 25500, 23500, 21500,20500 cycles respectively. Scanning electron microscope study of fracture surface at different locations was carried out to investigate modes of fracture due to heat treatments and filler compositions. The results reveal that presence of shiny surface along with tiny holes over the fracture surface leading to partial ductile.
Open Access
Performance and emission characteristics of diesel engine using castor oil methyl ester, diethyl ether and diesel oil blends
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Ramesh Kumar; Gupta, V.K.
Energy is a basic contribution for social and economic development. However, traditional or petroleum fuel resources are limited, non-renewable, polluting and, accordingly, should be utilized judiciously whereas renewable energy sources are indigenous, non-polluting and its availability is unlimited. In this way, their utilization ought to be supported in every possible way. The aim of this present work is to blend non edible oil Ricinus communis (Castor oil) biodiesel with diesel and diethyl ether in proposed percentage and to test the performance parameters such as brake power, fuel consumption, brake specific fuel consumption, brake thermal efficiency, and emission characteristics (exhaust temperature, smoke density and exhaust gas emissions) experimentally on 3.7 kW rated power, single cylinder four stroke compression ignition engine. From the current study it can be concluded that castor oil biodiesel is restricted to 40% volumetric blending with diesel for comparable characteristics such as performance and emissions as compare to the diesel. Increasing diethyl ether percentage leads to increased performance characteristics such as brake power, BSFC, BTE but decreased air fuel ratio. Emissions of CO2, CO, HC increased while NOX and smoke density decreased with increasing diethyl ether percentage. It is found that castor oil biodiesel when blended 20% in diesel gives best performance and emission characteristics at all loads.
Open Access
Exergy analysis of mobile air conditioning system and dual evaporator refrigeration system using ecofriendly alternatives of R134a
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-02) Jay Veer; Pratihar, A.K.
In the present study, exergy analysis of mobile air conditioning system with expansion work recovery and dual evaporator refrigeration system has been carried out using ecofriendly alternatives of R134a. The alternatives have low global warming potential as compared to R134a. Present model developed in EES has been duly validated with previous research work. The effect of evaporator temperature, expander isentropic efficiency, compressor isentropic efficiency, degree of subcooling and degree of superheating on system performance has been studied for both the systems. Mobile air conditioning system with expansion work recovery has been used to decrease throttling losses in the system. Exergetic efficiency was highest in case of R1234ze(E) whereas R1234yf has lowest exergetic efficiency among all the refrigerants studied. R450A and R513A have exergetic efficiency inferior to R134a but superior to R1234yf. Relative irreversibility of compressor was highest at lower evaporator temperature and at higher evaporator temperature; highest relative irreversibility was found in condenser. Total exergy destruction in the system was found to be highest for R513A and lowest for R134a. In dual evaporator refrigeration system, performance of the system is largely influenced by the evaporator with lower evaporating temperature. With increase in evaporator 2 (low temperature evaporator) temperature, average percentage decrease in COPs for R1234yf, R1234ze(E), R450A and R513A were found to be 5.32%, 0.61%, 2.86% and 3.27%, respectively when compared with R134a. Exergetic efficiencies for R134a, R1234yf, R1234ze (E), R450A and R513A are found to be 29.95%, 28.48%, 29.84%, 29.14 and 29.06%, respectively. Highest irreversible losses occurred in compressor and lowest in mixing chamber. Poorest performance is shown by R1234yf among all the refrigerants. R450A and R513A have been found to perform better than R1234yf.

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