Mechanical Engineering
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Mechanical Engineering
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Item Pedestrian-level Air Flow and Ventilation around Adjacent Buildings in Step-up Configuration(Nigeria Journal of Engineering and Applied Sciences (NJEAS), FUT Minna, 2017-08-24) Ayo, .S. A.; Mohd-Ghazali, .N.; Bori IgeThe outdoor air ventilation impact of a taller building at a downwind location in a layout of two adjacent buildings in different step-up configurations is presented in this paper. The criteria for ventilation assessment adopted are dimensionless parameters called velocity ratio (VR) and air ventilation rate (AER), and the parameters examined are the separation distance (WV) between the buildings and the ratio of height of downwind building to that of upwind building, herein referred to as building height ratio (HR). A three-dimensional (3-D) numerical simulation employing the Computational Fluid Dynamics (CFD) technique based on Reynolds-Averaged Navier-Stokes (RANS) equation and Realizable k-ε turbulence model was used to study the turbulent flow field around various full-scale size configurations of the adjacent buildings. Results show that while VR generally increases with height ratio, it increases with separation distance until a certain maximum distance which depends on the height ratio. AER on the other hand generally increases with height ratio, but decreases with separation distance. The results indicate that greater air motion is induced at the pedestrian level as the height of the downwind building increases, and greater rate of air flow is exchanged between the buildings cavity and the surroundings. Based on the VR results obtained for the building configurations examined, a separation distance of between 18 m and 30 m is proposed for configurations 2.0 ≤HR≤ 3.0, and between 18 m and 24 m for configurations HR = 1.0 and 1.5, to maximally invigorate the pedestrian-level air flow.Item Enhancing the Cavitation Erosion Resistance of 304 Stainless Steel by Laser Surface Alloying with Molybdenum(Nigeria Journal of Engineering and Applied Sciences (NJEAS), FUT Minna, 2017-08-24) Bori Ige; Muriana, .R. A.; Man, .H. C.; Okegbile, .O. J.; Ayo, .S. A.; Babawuya, .A.Type 304 stainless steel is the most versatile and widely used austenitic stainless steel, it accounts for more than 50% of all stainless steel produced. It is commonly used in liquidhandling equipment, house hold utensils and lot of applications in almost every industry. However, poor surface properties in terms of wear resistance, due to its low hardness made it susceptible to cavitation erosion, which is a usual mode of degradation of engineering parts in contact with fast-flowing or vibrating liquids. This work is an attempt to improve the cavitation erosion resistance of 304 stainless steel by laser surface alloying with Molybdenum (Mo). This was made possible by using a 2kW continuous wave Nd-YAG laser. The alloying powder was placed in advance on the surface of the substrate by pasting to a thickness of 0.1mm, followed by laser beam scanning at an optimal speed of 20 mm/s and 30 mm/s (each at a beam diameter of 3mm) and a laser power of 1.2kW, in order to achieve surface alloying and modified surfaces were obtained by 50% overlapping of adjacent tracks. The microstructure and composition of modified layer were also studied for more insights. Ultrasonic induced vibrator tester was used to carry out cavitation erosion test. Cavitation erosion resistance (Re) was observed to have increased with the Mo content in the alloyed layer, the Re of the specimens modified with Mo was improved by a factor of 1.4 (for v = 20 mm/s) and 1.5 (for v = 30 mm/s), when compared with that of the as-received 304 stainless steel substrates.Item DESIGN AND CONSTRUCTION OF A SMALL SOLAR POWERED AIR BLOWER FOR CHARCOAL FIRED FURNACE(JOURNAL OF THE NIGERIAN INSTITUTION OF MECHANICAL ENGINEERS, 2019-09-30) Muhammad, .A. B.; Nasir, .A.; Ayo, .S. A.; Bori IgeIn Nigeria almost all the local foundry shops rely on the manually operated blowers for supplying air for the combustion of the charcoals to melt metals. This manually operated blower has showed that much man-hour is required during firing as one laborer is dedicated to driving the rotary blower. This is labourous and reduces the rate of productivity of the enterprise. Therefore, it is necessary to find easier ways of supplying the energy required for the combustion so as to increase productivity. A solar powered blower is designed and constructed in this work. The performances of manually operated and solar powered air blowers are compared. Performance results of the manually operated air blower showed that it takes about 67 minutes and 42 minutes to melt 4kg of aluminum and zinc respectively. On the other hand, for the solar-powered air blower, it takes about 30 minutes and 17 minutes to melt 4kg of aluminum and zinc respectively. This indicates that the solar-powered air blower takes a shorter time to melt metals when compared with the manually operated air blower. In addition, the solar powered air blower eliminates the laborious aspect of supplying energy for melting metals and also reduces the times spent in metal melting process.Item INVESTIGATION OF PRESSURE TRANSIENTS AND WAVE PROPAGATION EFFECTS IN A PRESSURIZED PETROLEUM PIPELINE USING WANDA TRANSIENT SOFTWARE(Nigeria Journal of Engineering Science and Technology Research (FUT Yola), 2019-05-04) Muhammad, .A. B.; Nasir, .A.; Ayo, .S. A.; Bori IgePressure transients and effects of wave propagations due to instantaneous valve closure in a pipeline transporting premium motor spirit (PMS) were investigated using simulation approach in this paper. Pressure transient investigation and analysis are often more significant than the steady state analysis that hydraulic Engineers usually use in pipeline design because almost all pipelines experience pressure transient in their operations. Pressure transient analysis helps to understand the additional loads a pipeline can be subjected to as a result of instantaneous valve closures. In this paper, WANDA Transient 4.5.1210 commercial software was used for the analysis of the pressure transients due to instant valve closure in a petroleum pipeline. Three different instantaneous valve closure times of 4.5, 9 and 18 seconds were used in this investigation. It was observed in this research that rise in pressure is highest (1304 kPa) at node F (the node where the valve closure takes place) against the inlet pressure of 120 kPa and also there is drastic drop in pressure (-53.7 kPa) at node B (a node just upstream end of the pump). Also cavitations were observed at Node B due to the development of negative pressure as a result of the valve closure. The research recommends that surge tank should be installed at node F to stabilize the pressure surge and also air vessels are to be installed at node B to curtail damages due to cavitations.Item Hydraulic Transient Analysis in Fluid Pipeline: A Review(JOURNAL OF SCIENCE TECHNOLOGY AND EDUCATION , ATBU, BAUCHI, 2019-12-19) Muhammad, .A. B.; Nasir, .A.; Ayo, .S. A.; Bori IgeHydraulic transient is an important phenomenon in the pipeline transportation system that have adverse and catastrophic effects on the most susceptible pipeline components such as valve, pumps, pipes as well as the environment. The major causes of hydraulic transients are sudden or abrupt valve closure or pump failures as a result of power outage. The major challenges of transient analysis techniques are to optimally achieve a balance between accuracy of results obtained from the analysis and simplicity of the adopted techniques in analyzing both complex and simple pipeline networks. In order to attain this fit many researchers have proposed, developed and used different models and algorithms to this regards. This paper surveys various transient analysis techniques, model and algorithm for protection of pipeline network system with a view of achieving optimal trade-off between transient analysis techniques used and the type of fluid flow pipeline analyzed. Performance and limitations of some of the previous works are identified. Finally, future investigations on petroleum and its products were recommended.