Browsing by Author "Kareem, M.W."

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    A review of solar air heater for drying of agricultural products
    (Advanced Materials Research, 2014-02-27) Kareem, M.W.
    Bulk of farm products need to be preserved because of their perishable nature. The cheapest and environmental friendly means is indirect usage of solar irradiance to reduce the moisture content of these products to a level that cannot sustain the activities of micro-organisms. The research on solar collector has gained its popularity over the years due to man’s quest for green energy which has led to increase in demand for the utilization of solar energy. Harnessing of solar energy by man for drying purposes was predominantly by direct method which reduces the quality and quantity of the dried products. This work presents the most recent contributions on solar air heater of flat plate absorber category. Various models, material of component parts and performance efficiency of these air heaters were discussed and there is need for collector optimization. The study was concluded with a focus on multiple pass approach of solar harvesting.
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    Comparative study of single pass collector and double pass solar collector filled with porous media
    (Asian Journal of Scientific Research, 2013-01-15) Kareem, M.W.
    This research reports a comparative study of the convectional single pass flat plate collector and the double pass solar collector filled with porous media such as gravel and metal chips at the lower channel of the absorbing unit. The component materials, design, performance efficiencies, capabilities and the application of the solar collectors are presented to show various disparities that exist between the collectors. Emphasis was laid on the multi-pass approach as a gate way to future development on solar collectors.
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    Lumped component modelling of double pass solar collector with porous matrices
    (Applied Mechanics and Materials, 2014-02-10) Kareem, M.W.
    In this report, the modeling and simulation of a double pass solar air absorber was carried out using combination of Simscape and Simulink modeling tools. The solar system air mass flow rate and the porous media were critically investigated by using local weather data of Seri Iskandar, Perak, Malaysia. Optimal inlet air flow rate of 0.034kgm-2s-1 was obtained and one of the packed beds, sandstone extended the thermal transfer period of solar collector system by 1150s which displayed good agreement with the reported model and experimental outcomes. The results obtained have shown that it is a promising alternative tool for solar thermal experimentation modeling.
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    Numerical modelling of hot air multi-pass solar dryer
    (International Solar Energy Society Conference Proceedings, 2014-07-06) Kareem, M.W.
    This article presents the investigation of modeling solar drying system using partial differential equation module of MATLAB to predict the thermal conditions of a drying system with pebble beds as heat storage medium. A 2-dimensional geometry of the air heater was examined using both Dirichlet and Neumann boundary conditions to define the heat transfer and temperature gradient at the walls of the system. Appropriate thermal equations were used to define the multi-layer drying system with specific properties of materials which have significant effect on the performance efficiency of the solar collector. Finite element method of meshing the system component was employed to solve the heat transfer equation. The dynamic simulation of the air heater was tested for 5000 s at the average maximum daily temperature of 318 K with solar irradiation of 800 Wm-2. Despite five cabinet channels design, the temperature gradient of hot air distribution at various points was less than 1 K. The heat transfer simulation of the system has been achieved in good agreement with the reported studies. However, the mass transfer aspect of the model still needs to be improved upon for better and accurate collector characterization.
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    Random vortex element modelling of groundwater flow
    (World Academy of Science, Engineering and Technology, 2012-06-01) Kareem, M.W.
    Exploitation of groundwater for both domestic and industrial uses has continuously been undertaken in different parts of the world. The proper harnessing of available water required adequate analysis of the flow in the aquifer. Successful attempts have been made using finite difference and finite element methods. However, the possibility of vortex element method as an alternative technique was considered in this work. A model was developed using random vortex element method to simulate groundwater flow with constant head at the aquifer boundary. This was carried out by transforming the governing equation for groundwater flow into a typical vorticity equation for vortex method. The model was then used to determine groundwater head at varying time for Lagos basement complex with transmisivity and storativity of 5.5 X 10-5 m and 6.840796 X 10-2 respectively. The aquifer thickness varied from 4.0 m to 7.0 m. At the aquifer thickness of 4.0m the predicted groundwater heads varied from 0.0 m to 0.024833690 m, while at the aquifer thickness of 7.0m the predicted heads varied from 0.0m to 0.159134 m for varying time step at 0.1 s. The head differs only from literature value by 2.44%. Random vortex element method is therefore a viable numerical tool for predicting the groundwater flow parameters of the aquifer at any desired location.