Papers by Celestine Ebieto
Asian journal of medicine and health, Dec 19, 2023
Background: Facial analysis defines the measurement of soft tissue in the face used in forensics,... more Background: Facial analysis defines the measurement of soft tissue in the face used in forensics, anthropology, artistic design, and facial reconstruction. The study aims to evaluate the sexual differences in facial parameters among the Igbo ethnic group of Nigeria. Methods: 400 (200 males and 200 females) subjects of Igbo origin volunteered for the study. Each subject's frontal view photographs were taken in the Natural Head Position (NHP) and analyzed using Pro-Image Facial Software Version 2 to evaluate the nasal width, nasal height, mouth width, facial width, facial height, inner canthal distance, and outer canthal distance. Data obtained were analyzed with IBM SPSS (version 23) and independent T-test as an inferential statistic.
Blackbody radiation from a thin filament of SiC can be applied to measure hot gases temperature. ... more Blackbody radiation from a thin filament of SiC can be applied to measure hot gases temperature. The technique, Thin-Filament Pyrometer(TFP), exhibits fast temporal response and high spatial resolution owing to the very fine diameter and low heat conductivity. The advantage of this approach is the low cost and simplicity, and it is applicable to the situations where other approaches are difficult to apply. In this study, the investigation of methane-air flame propagating through a tube of a 20mm internal diameter quartz tube with open ends has been carried out. SiC fibres were installed at both ends and the midsection of the tube as radiation emitters. The required volume of methane at each equivalence ratio was measured and injected into the rig and the mixture was ignited at one end (left). The propagating flame was recorded using two highspeed cameras at a frame rate of 2000 fps with one tracking the speed of the flame and another capturing the images of the glowing filament. The images of the glowing filament were then processed to determine the surrounding gas temperature using the two-colour technique. Unlike the two-colour technique using beam splitting and narrow bandpass filtering approach, which often results in misalignment between two grey level images, complicated configuration and high cost, the current technique uses the camera built-in colour-banded filter. The ratio between two of the RGB primary channels was used for the calculation of the temperature. The maximum speed and temperature were observed at equivalence ratio 1.1 with a bellshaped curve. For cases where the flames were subjected to instabilities, the temperatures were found to fluctuate accordingly. The accuracy of TFP measurement was verified by a commercial Infra-pyrometer.
IOP conference series, Apr 1, 2021
International Research Journal of Innovations in Engineering and Technology, 2021
Simulations of two-phase (air and water) flow in a pipe are very relevant topics; however, with t... more Simulations of two-phase (air and water) flow in a pipe are very relevant topics; however, with the increased understanding of multiphase flow in pipes, the application of computational fluid dynamics (CFD) in other complex flow geometries involved in oil & gas industries are becoming more common. The current paper attempts to study two-phase flow characteristics in the horizontal concentric annulus using the CFD approach. The model was simulated in a concentric annulus test section with an overall length of 10.8m and outer diameter (OD) of 0.0768m and inner diameter (ID) of 0.060m. The model predicted the liquid holdup, and flow regime for the dispersed bubble flow. The volume of fraction (VOF) multiphase model and turbulence models (Realizable kε) were implemented to understand the gas and liquid holdup scenarios for flow in the horizontal annulus.
Global Journal of Engineering and Technology Advances, 2020
Several cases of the need for continuous utilization of gas turbines for power production and why... more Several cases of the need for continuous utilization of gas turbines for power production and why gas turbines will be relevant in the next 50 years in the Nigerian power sector are presented in this paper. Using 7 criteria; the cost of installation, operation and maintenance costs, levelized cost of electricity, capacity factor, the efficiency of energy conversion, power to size ratio/area coverage and environmental pollution, gas turbine operation was compared with wind and solar energy technologies. Gas turbine for power production appears to be more favourable in 5 out of the 7 criteria including lower installation cost which is a very important factor for poor and developing nations like Nigeria. The quantity of fuel for producing different quantities of power using gas turbines was estimated. Nigeria has huge proven reserves of natural gas which is the fuel for gas turbines. If we go for combined cycle power plants which have low specific fuel consumption (SFC), 50% of the nat...
European Journal of Engineering Research and Science, 2020
In the current research, experimental work is investigated for vertically and horizontally downwa... more In the current research, experimental work is investigated for vertically and horizontally downward propagating flames in an open-ended tube. The objective was to study and compare the influence of flammability limits, gravity, and the flame speed in the different tube configuration for two different fuels. The experimental facility included a 20 mm inner diameter tube, 1200 mm in length and an optical access quartz tube made centrally of 700 mm in length. Methane-air and propane-air fuel were compared for both vertically and horizontally downward propagating flames. The flame speed at each equivalence ratios for both fuels was lower for the flame that propagates downward compared to the flame that propagates horizontally. For both fuels, the flammability limits tend to rise for the vertically downward flame. The influence of gravity was seen as the flames become leaner and richer in methane-air and propane-air flames that propagate vertically downwards, causing a transformation in ...
Journal of Physics: Conference Series, 2019
The fabrication of a rapid compression machine (RCM) is in its early phase of design. The machine... more The fabrication of a rapid compression machine (RCM) is in its early phase of design. The machine is designed to enhance the study of ignition delay and validation of detailed kinetics models of fuels. The machine compresses fuel/air mixtures isentropically within 25 to 52 ms with a varying stroke. The combustion chamber design is not fixed and can be adjusted through the threaded shaft lock and within chamber slots. The originality of the facility is the inclusion of a pneumatic piston release mechanism (PPRM), which is pneumatically operated. The current test facility has been characterised by conducting a nonreactive and reactive experiment, the result showed that an obtainable compressed pressure of 21 bar and end gas temperature of approximately 1000 K was achievable within the present facility. The fidelity of the facility was performed with a non-reactive experiment, which experimental pressure profile was seen to follow each other closely showing that the data are highly rep...
Electrical Engineering Handbook, 2001
This paper presents process monitoring and control of machining operations. In this work, a cutti... more This paper presents process monitoring and control of machining operations. In this work, a cutting dynamometer mounted on the machine was used to measure the cutting force, cutting speed and the power consumed in the operation. The tool life was also calculated using the Taylor's equation. It was shown that when the cutting tool lifetime elapse, the tool no long give a good cut which imperatively indicates a deteriorating condition of tool life and possible failure.
Thermodynamic properties of R134a (1,1,1,2Tetrafluoroethane) and R718 (water) have been developed... more Thermodynamic properties of R134a (1,1,1,2Tetrafluoroethane) and R718 (water) have been developed as a Microsoft Excel add-in called ThermoAnalysis. The mathematical correlations for the thermodynamic properties of R134a and R718 were formulated from well-known equations of state and used to develop ThermoAnalysis based on a computer program in Microsoft Excel Visual Basic for Application language. ThermoAnalysis provides thermodynamic properties for the saturated regions for R134a and R718 refrigerants, and the subcooled and superheated regions of R718 refrigerant. The calculated values are accurate compared to the standard properties tables for refrigerants. A typical thermo-fluid problem was discussed to illustrate how ThermoAnalysis can be used for practical problem solving. Generated properties’ data can be easily used in the Excel spreadsheet for process analysis, simulation and design of systems that use R134a and R718. ThermoAnalysis is handy for both students and practicing...
Experimental work is reported for premixed flames propagating in tubes. The flames were ignited w... more Experimental work is reported for premixed flames propagating in tubes. The flames were ignited with a pilot flame and the flame propagation captured with high-speed cameras. Initial measurements were performed characterising the rig. These included investigations of the end configuration (open, closed, orifice plate) and whether the tube was horizontal or vertical. For horizontal tube open at both ends, the pressure signal of the propagating flame was recorded and the flame temperature distribution along the tube length was found by observation of a thin silicon carbide filament. The flame propagated steadily immediately after ignition with a curved front, then was subjected to oscillations at the middle of the tube. At the end of the tube, it regained its stability. The pressure and temperature of the propagating flame were highest at the middle point where the flame oscillated. Methane-air flames enriched with hydrogen were studied. As the hydrogen concentration was increased the...
One of the conditions for controlling the aerodynamics in the reaction chamber is designing a cre... more One of the conditions for controlling the aerodynamics in the reaction chamber is designing a crevice volume on the surface of the piston head. The importance of the crevice volume is to contain the cool boundary layers generated as a resulting of the moving reactor piston. However, this crevice volume consequently drops the end gas pressure and temperature at the end of the stroke. The CFD study of the aerodynamic effect of a piston movement in a reaction chamber was modelled using the commercial code of Ansys Fluent and assuming a 2-Dimensional computational moving mesh. A starting optimal crevice volume of 282 mm3 was used for further optimisation. This resulted in five crevice lengths of 3 mm, 5 mm, 7 mm, 9 mm and 12 mm, respectively. The crevice height of 5 mm was found to improve the compressed gas pressure at the end of the stroke to about 2 bar and temperature about 17.7 K and also maintained a uniform temperature field, while that of 12 mm had the least peak compressed gas ...
Journal of the Brazilian Society of Mechanical Sciences and Engineering
International Journal of Scientific and Research Publications (IJSRP)
In this paper, computer software is designed for optimum scheduling of timetable for courses in e... more In this paper, computer software is designed for optimum scheduling of timetable for courses in educational institutions. This system uses Dynamic Slot Algorithm (DSA) with the application of Constraint Satisfaction Programming. The algorithm was transformed into a program using Microsoft Excel-visual basic for application (Excel-VBA). It has been used for the timetable of the Faculty of Engineering, University of Port Harcourt. Results obtained are better than those generated manually by the human timetabler as they show a much higher space and time utilization, apart from the great speed associated with computer productions.
Fluid Dynamics Research
Experimental work is reported for premixed flames propagating in tubes. The flames were ignited w... more Experimental work is reported for premixed flames propagating in tubes. The flames were ignited with a pilot flame and the flame propagation captured with high-speed cameras. Initial measurements were performed characterizing the rig. For downwardly propagating flames to a closed-end, methane and propane were studied. The flames initially propagated steadily, then at approximately a third of the way down the tube, the primary acoustic oscillation sets in, resulting to a change in the flame shape. This was then followed by a plateau of variable length before a more violent secondary acoustic oscillation. In some circumstances, flames were observed to rotate due to the primary acoustic instability. The flame front position growth rate for both methane and propane were similar despite the differences in the fuels. The total acoustic loss time for propane and methane increases from the lean limit with the equivalence ratio, peaks at =1.1 and then decreases as the mixture becomes richer. There was also an increase in the total acoustic loss time as the angular speed of the flame increased. The results showed that the generation of acoustic energy for propane was smaller than that of methane due to the stronger natural damping effect of the former.
This work presents a comparative economic analysis of a simple and a modified cycle gas turbine p... more This work presents a comparative economic analysis of a simple and a modified cycle gas turbine power plants. The basic engine used for this work is a PG 6581 B gas turbine engine which is operated by a company in the Niger Delta area of Nigeria. The modified cycle was developed from the simple cycle engine with an intercooler between two compressors, a reheater between two turbines and a regenerator which heats up the second compressor exit gases with the second turbine exit gases. The net present value and the levelized cost of electricity methods were applied to investigate the economic viability of the two plants. The modified cycle was analyzed at regenerative effectiveness values between 80% and 100%. The fuel flow rate in the simple cycle plant was obtained from the field as 2.13 kg/s while the total fuel flow rate in the modified cycle ranged from 2.41kg/s to 2.08kg/s. The power output in the simple cycle plant was 35.52MW while that in the modified cycle plant ranged betwee...
European Journal of Engineering Research and Science
Engineering education is incomplete without laboratory practices. One of such laboratory equipmen... more Engineering education is incomplete without laboratory practices. One of such laboratory equipment necessary for all engineering students to have hands-on in the course of their undergraduate studies is the heat exchanger. This work presents the detailed design and construction of a laboratory type double pipe heat exchanger that can be used both in the parallel and counter flow configuration. The heat exchanger was constructed using galvanized steel for both the tube and shell. Experiments were designed and carried out to test the performance of the heat exchangers. The heat exchanger performance characteristics (logarithm mean temperature difference (LMTD), heat transfer rate, effectiveness, and overall heat transfer coefficient) were obtained and compared for the two configurations. The LMTD tends to be relatively constant as the flow rate was increased for both the parallel and counter-flow configuration but with a higher value for the parallel flow configuration. The heat excha...
Advances in Science and Technology Research Journal, 2019
One of the conditions for controlling the aerodynamics in the reaction chamber is designing a cre... more One of the conditions for controlling the aerodynamics in the reaction chamber is designing a crevice volume on the surface of the piston head. The importance of the crevice volume is to contain the cool boundary layers generated as a resulting of the moving reactor piston. However, this crevice volume consequently drops the end gas pressure and temperature at the end of the stroke. The CFD study of the aerodynamic effect of a piston movement in a reaction chamber was modelled using the commercial code of Ansys Fluent and assuming a 2-Dimensional computational moving mesh. A starting optimal crevice volume of 282 mm3 was used for further optimisation. This resulted in five crevice lengths of 3 mm, 5 mm, 7 mm, 9 mm and 12 mm, respectively. The crevice height of 5 mm was found to improve the compressed gas pressure at the end of the stroke to about 2 bar and temperature about 17.7 K and also maintained a uniform temperature field, while that of 12 mm had the least peak compressed gas pressure. This study investigated the possible means of improving the peak pressure and temperature drop in a rapid compression machine by further optimisation of the crevice volume.
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Papers by Celestine Ebieto