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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.
Open Access
Development and evaluation of multi-nozzle backpack type power sprayer
(Punjab Agricultural University, Ludhiana, 2018) Avesh Kumar Singh; Manes, G.S.
The study deals with the development and evaluation of multi-nozzle backpack type power sprayer, which can be used to spray at all stages of cotton crop by using the boom both in horizontal (during early stages of crop) and in vertical (during maturity stage) position. Three types of nozzles N1, N2 and N3 were evaluated in laboratory using patternator at three nozzle pressures P1 (3.0 kg/cm2), P2 (4.5 kg/cm2) and P3 (6.0 kg/cm2) and at three target distance D1 (540 mm), D2 (340 mm) and D3 (250 mm) respectively. Based on laboratory results, rate of discharge, angle of spray and swath width were found non-significant for nozzle N1 & N3. Thereby, Nozzle N1 and Nozzle N2 were selected for mounting on the boom according to overlapped pattern (minimum CV) of nozzle N1 and Nozzle N2 at a pressure of 3.0 kg/cm2 at different target distance. The sprayer was evaluated in the field for spraying on cotton crops at four different stages of growth (60,75,90 and 105 DAS) by fixing water sensitive paper on the plant at three locations of plant canopy (up and down of leaf). Uniformity coefficient and droplet density varied from 1.19 to 2.91 and 34.33 to 76.67. However, at a particular stage of crop the uniformity index and droplet density for some combination of locations was found non-significant thus depicting uniform spray. Field capacity for Nozzle N1 and N2 decreased from 0.34 ha/h to 0.09 ha/h and 0.28 ha/h to 0.09 ha/h when the position of boom was changed from or horizontal to vertical positions. Fuel consumption for spraying with nozzle N1 and nozzle N2 increased from 0.42 l/h to 0.60 l/h and 0.37 l/h to 0.50 l/h when the position of boom was changed from horizontal to vertical positions.
Open Access
Mathematical Formulation of Groundwater Recharge through Abandoned Well
(Punjab Agricultural University, Ludhiana, 2018) Gupta, Alok; Aggarwal, Rajan
The stress on groundwater resources is continuously increasing due to rampant use in agriculture, increasing urbanization, industrialization and population. As a result, the groundwater levels in various parts of the country are declining. Groundwater recharge is one of the water augmentation techniques by which run-off water or excess water can be put into aquifer itself to replenish the groundwater reservoir. For recharging groundwater, one may use variety of methods such as abandoned well, ponds and pits. A field study was done to evaluate the recharge through abandoned well in an unconfined aquifer. The canal water was diverted into the abandoned well, maintaining constant head conditions. The study showed that rate of recharge decreased from 9.18 l/s to 3.4 l/s with time. Major factor responsible for this reduction was the total suspended solids (TSS) of canal water. An analytical equation was developed to simulate rise in water table, assuming the recharge taking place from a hypothetical well screen fully penetrating the saturated thickness of the aquifer. The developed mathematical equation was able to predict the rise in water table reasonably well under existing field conditions.
Open Access
Impact of Landuse Change on Runoff and Sediment Yield of a Watershed in Shivalik Foot-Hills
(Punjab Agricultural University, Ludhiana, 2018) Sushanth, Kallem; Bhardwaj, Anil
Landuse change significantly alters the hydrologic characteristics of the land surface within a watershed. In the present study, the impact of landuse change (2006 - 2016) on runoff and sediment yield has been assessed in Patiala-Ki-Rao watershed located in Shivalik foot-hills, using RS, GIS and WEPP watershed model. Landuse maps were generated in GIS environment using LANDSAT imageries for the years 2006 and 2016 with overall classification accuracy and Kappa statistic both above 0.9. The watershed was classified into seven major landuse classes namely agriculture, built-up, fallow land, forest, grass land, streams and water bodies. The analysis of landuse maps indicated that the area under all the landuses decreased except built-up that increased by 372.27 ha (112.04%) in a period of 10 years. Change detection matrix was prepared to determine land encroachment by different landuse categories. Forest is the most affected landuse among all watershed landuses that shrinked by 194.90 ha followed by agriculture (64.57 ha), grass land (50.81 ha), streams (30.42 ha), fallow land (21.86 ha) and water bodies (9.72 ha). Runoff and sediment yield for the landuse of the years 2006 and 2016 were simulated by the WEPP model using climatic data for the year 2006 and again with that of the year 2016. The simulated runoff, sediment yield and sediment delivery ratio got increased from 53.70 mm to 63.70 mm (18.62%), 10.20 Mg/ha to 15.10 Mg/ha (48.04%) and 0.192 to 0.254 (32.23%) under climate-2006 and 64.60 mm to 81.90 mm (26.78%), 12.90 Mg/ha to 16.80 Mg/ha (30.23%) and 0.261 to 0.303 (16.09%) under climate-2016 due to change in landuse during the study period of 10 years. Runoff coefficient increased from 0.054 to 0.064 under climate-2006 and 0.058 to 0.074 under climate-2016 for landuse of the years 2006 and 2016, respectively. However, threshold value of rainfall that produced runoff decreased from 15 mm to 9 mm under climate-2006 and 15 mm to 11 mm under climate-2016 for the years 2006 and 2016, respectively. Hillslope and channel slope soil loss also increased significantly due to landuse change in the watershed.
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Performance evaluation and simulation of solar photovoltaic pumping system round the year
(Punjab Agricultural University, Ludhiana, 2018) Mahekpreet Kaur; Garg, Sunil
The present study was undertaken to analyze the performance of solar photovoltaic (SPV) pumping system parameters, variation of solar insolation and amount of water pumped per month under different seasons. The average flow rate in summer, monsoon, post monsoon and winter season was 3.0 Lps, 2.17 Lps, 3.44 Lps and 2.93 Lps, respectively. The amount of water pumped in summer, monsoon, post monsoon and winter season was 110.7m3/9hr/day, 75.16 m3/9hr/day, 105.93 m3/9hr/day and 83.98 m3/7hr/day, respectively. The average conversion efficiency in summer, monsoon, post monsoon and winter season was 14.36 %, 15.13 %, 17.04 % and 16.85 %, respectively. Based on this relationship between solar irradiance and flow rate; panel temperature and conversion efficiency under different seasons were developed. The major factor which influences the performance of any SPV pumping system is the conversion efficiency and conversion efficiency is significantly affected by the panel temperature. The range of optimum panel temperature should be between 12 ˚C to 32 ˚C at which conversion efficiency will be maximum varying from 18.39 % to 21.0 %. The relationship between solar irradiance and flow rate during summer, monsoon, post monsoon and winter season followed linear equation having R2 value of 0.70, 0.89, 0.81 and 0.92, respectively. The relationship between panel temperature and conversion efficiency during summer, monsoon, post monsoon and winter season followed linear equation having R2 value of 0.75, 0.83, 0.71 and 0.78, respectively. The presence of clouds significantly affected/lowe-red down the current, RPM and flow rate but the temperature did not change much which reveals that temperature has minimum effect on the development of current and voltage in solar photovoltaic cells. Flow rate was estimated using utilizability method and simulated by PV SYST model. The coefficient of variation between estimated flow rate by utilizability method and measured flow rate and simulated flow rate and measured flow rate was found to be 9.00 % and 15.08 %, respectively.
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Performance evaluation of double layered polyethylene greenhouse solar dryer for drying of selected horticultural produce
(Punjab Agricultural University, Ludhiana, 2017) Pinki; Mahesh Kumar
The present study was conducted with an objective to evaluate the performance of double layered greenhouse solar dryer for drying of horticultural crops cabbage, spinach, onion and carrot that uses solar energy. Greenhouse solar dryer used was of 10×6 square ft area with polyethylene layering over trays. Exhaust fan was used at speed of 2.08 m/sec for forced convection. The performance evaluation of greenhouse solar dryer was done for drying of cabbage, spinach, onion, carrot and compared with open sun drying, single layer natural convection solar drying, double layer natural convection solar drying, single layer forced convection solar drying, double layer forced convection solar drying. All the four crops cabbage, spinach, onion and carrot were given physical treatment i.e. cutting; drying kinetics of all the crops chosen was studied by open sun drying, single layer natural convection solar drying, double layer natural convection solar drying, single layer forced convection solar drying, double layer forced convection solar drying techniques. The quality parameters included colour, ascorbic acid, polyphenol content, shrinkage ratio, rehydration ratio and overall acceptability. Double layer solar drying under forced convection took the minimum drying time i.e. 480, 275, 585, 385 min for cabbage, spinach, onion, carrot respectively followed by double layer solar drying under natural convection i.e. 785, 495, 665, 885 min for cabbage, spinach, onion, carrot respectively; accompanied by final moisture content 6-7% (db) for all crops. The quality of double layer solar drying under forced convection found comparable with open sun drying.
Open Access
Recovery of sensible heat from air leaving drying chamber of conventional forced circulation solar dryer
(Punjab Agricultural University, Ludhiana, 2017) Simranjeet Singh; Sukhmeet Singh
Air leaving drying chamber of conventional solar crop dryers is at higher temperature than ambient which leads to wastage of energy. Therefore it is proposed to use thermal storage at exit of the drying chamber of solar dryers to extract heat from leaving air, which can later on be utilised. In this research work, the proposed method is tested for conventional forced circulation solar dryer. The setup consists of multi-tray drying chamber, air heating unit, electric air blower and sensible heat storage unit. Crushed rocks were used for sensible heat storage. Electric heaters were used instead of solar air heaters to have control over drying air temperature. Heat recovery was tested for extending drying operation in two scenerios, namely, with thermal storage only and thermal storage along with auxiliary heating. Evaluation was done at constant inlet air temperatures of 55, 60, 65 and 70oC and fixed air mass flow rate of 0.025 kg/s. 5.850 kg fresh carrots were loaded in each experiment. It was found that thermal storage at exit of drying chamber is beneficial in both cases. During testing, 1.08-9.41% energy savings were achieved along with extended drying operation. Further, heat recovery supplemented by auxiliary heating proved to be more effective. For drying at 60oC, recovered energy was 1.53 MJ and 1.7 MJ with and without auxiliary heating. Computer model has also been developed to predict drying rate for the same setup using air from solar air heater.
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Effect of angle of attack on heat transfer and friction characteristics of inclined rib roughened solar air heater duct
(Punjab Agricultural University, Ludhiana, 2017) Gurpreet Singh; Hans, V.S.
Thermal performance of solar air heaters is very low due to formation of laminar sublayer over the heat transferring surface. By use of artificial roughness in the form of wires, thermal performance of solar air heaters can be increased considerably. This study represents an experimental investigation carried out to examine the effect of angle of attack on heat transfer and friction characteristics of inclined rib roughened solar air heater duct. The various parameters related to roughness geometry and flow were Reynolds number in the range of 2000 to 16000, relative roughness height (e/D) in the range of 0.02 to 0.043, relative roughness pitch (P/e) in the range to 6 to 14 and angle of attack (α) in the range of 45o to 75o: The results obtained from this experimental investigation suggested that ribs inclined at 67o, having relative roughness pitch and relative roughness height value of 10 and 0.043 respectively outperformed the other rib configuration in terms of thermal and thermo-hydraulic performance. Correlations for Nusselt number and friction factor in terms of roughness geometry parameters and flow parameters have also been developed from experimental data.
Open Access
Software development for determining quality and maturity levels of tomato using image processing techniques
(Punjab Agricultural University, Ludhiana, 2017) Kamalpreet Kaur; Gupta, O.P.
Agriculture contributes a lot in the economic development of India. Maturity checking has become mandatory for the food industries as well as for the farmers so as to ensure that the fruits and vegetables are not diseased and are ripe. However, manual inspection leads to human error, unripe fruits and vegetables may decrease the production. Thus, this study proposes a Tomato Classification system for determining maturity stages of tomato (Green, Breaker, Pink, Light-Red and Red- Mature) through Machine Learning using Image Processing approach. Design and development of software has been implemented using Pycharm as an IDE and Python as a programming language. The method consists of image collection, preparing database and training seven different classifiers on 80% of the total data for evaluating the maturity stages of tomato using the surface color as an attribute. Rest 20% of the total data is used for the testing purpose. The results are obtained in the form of Learning Curve, Confusion Matrix and Accuracy Score. The Graphical User Interface (GUI) for Tomato Classification by using Python is achieved. It is observed that out of seven classifiers, Random Forest is successful with 92.49% accuracy in evaluating the maturity category of tomato. It is concluded from the results that the performance of the classifier depends on the size and kind of features extracted from the data set.

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