Browsing by Author "Rajakaruna, Hobina"
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Item Metadata only Experimental and simulation studies on a single pass, double duct solar air-heater.(Elsevier, 2003-01-01) Forson, Francis Kofi; Nazha, Marouan A. A.; Rajakaruna, HobinaA mathematical model of a single pass, double duct solar air heater (SPDDSAH) is described. The model provides a design tool capable of predicting: incident solar radiation, heat transfer coefficients, mean air flow rates, mean air temperature and relative humidity at the exit. Results from the simulation are presented and compared with experimental ones obtained on a full scale air heater and a small scale laboratory one. Reasonable agreement between the predicted and measured values is demonstrated. Predicted results from a parametric study are also presented. It is shown that significant improvement in the SPDDSAH performance can be obtained with an appropriate choice of the collector parameters and the top to bottom channel depth ratio of the two ducts. The air mass flow rate is shown to be the dominant factor in determining the overall efficiency of the heater.Item Metadata only Experimental investigations of a chimney-dependent solar crop dryer.(Elsevier, 2008) Afriyie, John Kwasi; Nazha, Marouan A. A.; Rajakaruna, Hobina; Forson, F. K.Item Metadata only Mathematical modelling and validation of the drying process in a chimney-dependent solar crop dryer(Elsevier, 2013-03) Afriyie, John Kwasi; Rajakaruna, Hobina; Nazha, Marouan A. A.; Forson, F. K.A simulation procedure describing the drying process within a Chimney-Dependent Solar Crop Dryer (CDSCD) has been developed. The simulation follows the authors’ experimental work on the effect of varying drying chamber roof inclination on the ventilation and drying processes, and their work on the development of simulation code to help optimise ventilation in such dryers. The current paper presents the modelling and subsequent validation of the drying process inside the dryer, to come out with a design tool for the CDSCD. The work considers the height of the crop shelf above the drying-chamber base, crop resistance to airflow and the shading on the drying-chamber base and their effects on the drying process. The under-load condition temperatures and velocities are predicted to within a relative difference of 1.5% and 10%, respectively of the observed values. Even though the heat inertia of the physical model causes deviation between the predicted drying path and the observed drying path, the two paths tend to converge at the end of each drying cycle, with a general prediction to within 10% relative difference of the observed crop moisture content. The validation results show that the simulation code can serve as an effective tool for comparing and refining the designs of the CDSCD for optimum drying performanceItem Metadata only Modelling and experimental studies on a mixed-mode natural convection solar crop dryer.(Elsevier, 2007-03-01) Forson, Francis Kofi; Nazha, Marouan A. A.; Rajakaruna, HobinaItem Metadata only Prediction and measurement of soot particulate formation in a confined diesel fuel spray-flame at 2.1 MPa(Elsevier, 2003-01-01) Crookes, R. J. (Roy J.); Sivalingam, G.; Nazha, Marouan A. A.; Rajakaruna, HobinaItem Metadata only Simulation and optimisation of the ventilation in a chimney-dependent solar crop dryer.(Elsevier, 2011) Afriyie, John Kwasi; Rajakaruna, Hobina; Nazha, Marouan A. A.; Forson, F. K.Item Metadata only The use of emulsion, water induction and EGR for controlling diesel engine emissions.(SAE, 2002-09-01) Nazha, Marouan A. A.; Rajakaruna, Hobina; Wagstaff, S. A.