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- ItemUnsteady performance of degraded compressor and turbine blades of an aero-engine at varying ambient and turbine inlet temperatures(FETiCON, 2023-08-04) I. O. Otaiku; I. O. OtaikuThe paper presents the modelling of unsteady performance of a degraded 4-stage compressor and single stage gas generator turbine blades of PT6T turboshaft aero-engine of a helicopter. The two sections were set as control volumes for analytical and numerical modeling. Numerically, The blade specimens (NACA 65 series) were developed using SOLIDWORKS 20 and simulations performed with FLUENT in ANSYS 20.0. The RANS (Reynolds-averaged Navier–Stokes) equations with Shear Stress Transport model SST (k-w) were chosen for the unsteadiness of pressure and temperature distributions over different levels of reductions in surface area of the blades’ pressure side. 900 x 103 mesh elements size were selected and the boundary conditions-inlets for the two control volumes were 295-325 K and 1083 – 1245 K for compressor and turbine respectively. Analytically, equations for different levels of degradations (surface area reductions) were developed to determine their flow performance at new pressure and temperature for compressor (∆P_2C,∆T_2C) and turbine (∆P_3T,∆T_3T) with change in time and the corresponding rise in centrifugal stress. Results from FLUENT predicts the performance of the sections for 10% surface area reduction with complex structure in the turbulent flow imposes high fatigue stress, hence shows the highest closeness to surge margin. For the compressor, the result emphasizes the impact of inlet conditions on degraded blades over exit conditions. Also in the turbine, velocity contour shows adverse/backward flow as a result of high turbulence formation and rising fatigue due to change in exit pressure flow from stage to stage in the compressor. This exit pressure determines the TIT in the turbine which is a function of efficiency of the single stage gas generator turbine and is crucial to the overall efficiency of the engine and the safety of the engine as a whole. In conclusion, the inter-component flow behaviour between the degraded compressor and turbine as revealed in this study shows the near real-life situation of the engine performance. Summarily, the accurate engine life estimation can be deduced from TIT rising from 1100-1200 K and centrifugal stress 60MN/mm2.
- ItemAn Evaluation of Predictive Modeling and Error Analysis for Physicochemical Characteristics of Gasoline-Bioethanol Blends in a Gasoline Engine(American Journal of Engineering Research (AJER), 2024-12-07) Ogunsola A. D.; Alajede A. M.; Olafimihan E. O.; Sangotayo E. O.; Aderibigbe A. A.; Sulaiman A. O.The integration of bioethanol into gasoline blends has gained significant attention for improving engine performance and reducing environmental impacts. This study evaluated predictive modeling and error analysis of the physicochemical characteristics of gasoline-bioethanol blends (E0, E5, E10, and E15) in a four-stroke gasoline engine. The importance of optimizing blend ratios for efficiency and sustainability underscores the relevance of this research. The physicochemical characteristics, including cetane number, viscosity, density, carbon residue, and heating values, were measured using a data logger and analyzed across blend ratios ranging from 0% to 15%. Profiles of these characteristics were created to assess their relationship with bioethanol content. Predictive models were developed using SAS software, with R-squared and RMSE values evaluated as performance metrics to assess model accuracy and fitness. The results indicate that the coefficient of performance (COP) demonstrated higher sensitivity to bioethanol content in the 0-10% range, stabilizing about10%, suggesting an optimal blend ratio of around 10%. Brake power efficiency decreased linearly with increasing bioethanol content due to the lower energy density of higher ethanol blends. However, the enhanced combustion efficiency of bioethanol compensated for some efficiency losses. Notably, the E10 blend achieved the highest brake power of 391.65 W, Model evaluation revealed robust predictive capabilities, with R-squared and RMSE values for COP at 0.964 and 0.585, respectively, and for braking thermal efficiency at 0.996 and 0.133, respectively. These metrics confirm the model's high accuracy and reliability in predicting engine performance characteristics across blend ratios. Future research should explore the impact of higher ethanol concentrations on engine durability and further optimization of bioethanol-gasoline formulations for enhanced sustainability and effectiveness.
- ItemThe Influence of Thermophysical Properties on The Heat and Flow Characteristics of a NanoLubricant Based on Aluminum Oxide(International Journal of Engineering Research & Technology, 2024-12-07) Itabiyi, O. E.; Sangotayo, E.O; Muraina, A. B.; Akinrinade, N.A.; Sulaiman A. O.; Olojede, M.A.The potential of nano-lubricants to improve heat transfer and flow characteristics in a variety of engineering applications has motivated a significant amount of interest in the study of their thermophysical properties in recent years. This paper examined the influence of thermophysical properties, including thermal conductivity, viscosity, density, and specific heat capacity, on the heat and flow behavior of aluminum oxide (Al₂O₃)-based nanolubricants that are flowing through a cylindrical channel. The governing equations for momentum and energy were converted to non-dimensional form and solved using a finite difference scheme that was implemented in C++. The analysis examined the impact of thermal conductivity (0.3<κ<1.5), viscosity (0.001<μ<0.3), density (998< ρ <3592), heat capacity (1100 < Cp < 4200), and the Eckert number (1.0
- ItemUnveiling the Future: A Survey of Electric Propulsion Systems and their Pivotal Role in Shaping the Next Frontier of Space Exploration(Science Publications, 2024-01-04) Jinadu Abdulbaqi; Okikijesu Omolona Olajide; Akangbe Tunde AyodejiElectric propulsion represents the future of space travel, which is a promising technology for Earth-orbital and deep space missions, including potential applications in human Mars missions. The past decade has witnessed substantial progress in the conceptualization and experimentation of electric thrusters and their propellants, signaling a transformative era in space exploration. This review provides an overview of the comparison between electric and chemical propulsion, followed by a detailed examination of current research and development on various types of electric propulsion thrusters. The discussion encompasses the adoption of diverse technologies to enhance the scalability of these thrusters, presenting a comprehensive outlook on the future of space exploration.
- ItemLiquid Nitrogen Injection into Aviation Fuel to Reduce its Flammability and Post-Impact Fire Effects(Vilnius Tech, 2023-01-25) Jinadu Abdulbaqi 1*,; Jinadu Abdulbaqi; Olayemi Adebayo Olalekan; Koloskov Volodymyr; Akangbe Ayodeji; Tiniakov DmytroThe finite volume method was used to study the characteristic of contaminated aviation fuel with the aim of reducing its flammability and post-impact fire. The flammability levels between pure Jet A-1 and contaminated Jet A-1 are compared using their flashpoints and fire points before and after the introduction of Liquid Nitrogen. Upon heating different mixing ratios (4:1, 3:1, and 2:1), results are analyzed to identify the best volume ratio exhibiting the highest reduction in flammability. Analysis shows that the mixing ratio of 2:1 not only froze but increased the flashpoint of the mixture from (48 ˚C–50 ˚C) to 64 ˚C. For the mixing ratio of 3:1, there was a rise in flashpoint to about 56 ˚C and partial freezing was seen at the topmost surface. At a mixing ratio of 4:1, it was observed that the effect of liquid nitrogen on Jet A-1 was minimal leading to a slight rise in its flash point (50 ˚C). Thus, liquid Nitrogen had a substantial effect on the flammability and flash point of Jet A-1 when mixed in the ratio (2:1) with a freezing time of 30 seconds and an unfreezing time of 17.5 minutes. Hence, Liquid Nitrogen can be used for the flammability reduction of Jet A-1.