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Thesis

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2017 - 20182
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Subject: Mechanical Engineering × End date: 2018 × Start date: 2016 × Type: Thesis × Thesis Type: M.Tech. ×
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    Computational Fluid Dynamics of Solar Air Heater Duct Roughened with Multiple Arc Rib having Gap and Staggered Rib Piece
    (Punjab Agricultural University, Ludhiana, 2018) Amanpreet Kaur; Hans, V.S.
    Artificial roughening of solar air heater duct wall is the effective method which leads to significant enhancement in heat transfer as well comparable rise in friction losses. The different investigations have been performed by various authors to study the heat transfer rate and friction factor characteristics. In this present study, a numerical investigation is carried out using Computational Fluid Dynamics software ANSYS Academic Research CFD 15.0 to determine the heat transfer rate and thermo-hydraulic performance of rectangular solar air heater duct roughened with multiple arc rib having gap and staggered rib piece. The parameters considered were relative roughness pitch of 8, relative roughness height of 0.043, relative roughness width of 5, relative gap width of 1, arc angle of 60° and relative staggered rib size of 4. The investigation encompassed for the Reynolds number and relative staggered rib pitch range from 2000 to 18000 and 0.2 to 0.8 (4values) respectively. The maximum enhancement in Nusselt number and friction factor was observed to be 3.38 and 6.2 times as compared to smooth duct at relative staggered rib pitch of 0.4. The maximum thermo-hydraulic performance found to be 1.83 for relative staggered rib pitch of 0.4 at Reynolds number of 12000.
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    ThesisItemOpen Access
    Development of a thermal model and performance evaluation of twin-chamber community solar cooker
    (Punjab Agricultural University, Ludhiana, 2017) Sekhon, Mandeep Singh; Sethi, V.P.
    In this study, a twin-chamber community solar cooker is experimentally evaluated and global solar radiation availability and thermal model has been developed for selected latitudes and different seasons of the year. A mathematical program was developed and utilized to compute monthly average daily solar insolation, hourly solar insolation and instantaneous solar intensity captured by the solar cooker for use in the developed thermal model. The computed values of solar radiation were validated for 300N latitude (Ludhiana) and were found to be in close proximity with the predicted values. The solar radiation captured was utilized in developed thermal model by solving energy balance equations and validating them for chamber air and absorber plate temperature. The cooker was tested as per BIS standards (IS Code – 14329) for calculation of first figure of merit (F1), second figure of merit (F2) and standard boiling time (τ). It was observed that F1, F2 and τ were 0.128, 0.41 and 181 minutes respectively which shows that the designed cooker is ‘A’ grade cooker. Economic analysis was performed to compute the payback period and net present value and it was observed that the cooker can save 47 cylinders or 668 kg of LPG in one year. Environmental impact analysis was also performed to compute the carbon credits earned by using the designed solar cooker in substitution of conventional cooking fuels. It was observed that carbon credits earned in a year in substitution of fuels like cow dung cake, wood and LPG were 5.9, 4.1 and 2.0 respectively.