Investigating the impact of velocity fluctuations and compressibility to aerodynamic efficiency of a fixed-wing aircraft

Ejeh, Chukwugozie Jekwu; Afgan, Imran; Shittu, Remilekun; Sakirudeen, Alabi; Anumah, Prosper

doi:10.1016/j.rinp.2020.103263

Cited by 10 publications

(5 citation statements)

References 19 publications

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“…Simulation of the interaction of the atomizing gas flow with the obstacles (electrodes) was performed using ANSYS CFX simulation [33,34] based on the solutions of the Navier-Stokes equations under the following boundary conditions: airflow pressure is 0.56 MPa, temperature is 20 • C, and air density is 1.2754 kg/m 3 . Experimental investigation of the airflow dynamic structure was performed through "shadow" photographing described in [35].…”

Section: Methodsmentioning

confidence: 99%

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

2021

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The paper aims to investigate the airflow dynamics of electric-arc spraying (EAS) with airflow pulsation. The study is focused on the dynamic structure of the airflow with an obstacle in the form of crossed electrodes at the steady and the pulsating air supply (with a frequency up to 120 Hz). The work was fulfilled using a computer simulation, the airflow “shadow” photo visualization, and the microstructure characterization of the coatings formed. It was found that when air flows along the crossed electrodes with a gap of 2 mm, a depression zone appears in the flow with a pressure drop from 0.56 MPa to 0.01 MPa. The air pulsation resulted in a change in a flow’s dynamic structure towards an increase in the length of the depression zone, which covers most of the arc, affecting the liquid metal oxidation. It is established that the frequency of a droplet formation should match the frequency of the airflow pulsation to minimize the metal oxidation. With the air pulsating at about 65 Hz, the oxide volume fraction in the aluminum coating was reduced by 3.6 times compared to the steady airflow. EAS with airflow pulsation has the potential for technological cost reduction.

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Section: Methodsmentioning

confidence: 99%

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

2021

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“…A second-order central differencing scheme was used for flow parameters, whereas the turbulent properties were discretized using the van Leer scheme (Van Leer [ 55 ]). The numerical treatment and discretization techniques utilized in this study have already been extensively benchmarked over a wide range of thermal-hydraulic and renewable energy configurations, see Afgan et al [ 56 ], Filippone and Afgan [ 57 ], Guleren et al [ 58 ], Han et al [ 59 ], Wu et al [ 60 ], Wu et al [ 61 ], Wu et al [ 62 ], Kahil et al [ 63 ], Benhamadouche et al [ 64 ], Nguyen et al [ 65 ], Ejeh et al [ 66 ], Ejeh et al [ 67 ], Revell et al [ 68 ], Ahmed et al [ 69 ], Ahmed et al [ 70 ], McNaughton et al [ 71 ] and Abed et al [ 72 ]. The boundary conditions applied in the current study are summarized below:…”

Section: Numerical Modelingmentioning

confidence: 99%

Thermal-Hydraulic Analysis of Parabolic Trough Collectors Using Straight Conical Strip Inserts with Nanofluids

et al. 2021

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In this study, we numerically investigated the effect of swirl inserts with and without nanofluids over a range of Reynolds numbers for parabolic trough collectors with non-uniform heating. Three approaches were utilized to enhance the thermal-hydraulic performance—the variation of geometrical properties of a single canonical insert to find the optimized shape; the use of nanofluids and analysis of the effect of both the aforementioned approaches; the use of swirl generators and nanofluids together. Results revealed that using the straight conical strips alone enhanced the Nusselt number by 47.13%. However, the use of nanofluids along with the swirl generators increased the Nusselt number by 57.48%. These improvements reduced the thermal losses by 22.3% for swirl generators with nanofluids, as opposed to a reduction of only 15.7% with nanofluids alone. The investigation of different swirl generator designs showed various levels of improvements in terms of the overall thermal efficiency and thermal exergy efficiency. The larger swirl generator (H30mm-θ30°-N4) with 6% SiO2 nanofluids was found to be the optimum configuration, which improved the overall collector efficiency and thermal exergy by 14.62% and 14.47%, respectively.

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“…Crude oil and water are considered as the primary and secondary phases in this work, respectively. (Ejeh et al, 2020b). A variable is assigned to each additional phase introduced in the simulation.…”

Section: Multi-phase Flow Modelingmentioning

confidence: 99%

Improving flow efficiency in curved pipes during multi-phase, immiscible fluid flow using edge-tailored guide vanes

Ejeh

Alawwa

Kofi

et al. 2021

Exp. Comput. Multiph. Flow

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High static pressure due to flow transitioning associated with recirculation, mixing, and separation around a pipe bend is a possible cause for a decrease in flow efficiency. This paper aims to use edge-tailored guide vanes to ease flow transition and improve flow efficiency, numerically. Here, flow efficiency serves the purpose for qualifying the effectiveness of the proposed technology.Sensitivity studies were performed on the influence of number of guide vane and guide vane thickness in a 45° pipe elbow. In setting up the numerical model for the assumed two-phase flow system (crude oil and water), the volume of fluid model was activated to model time-dependent fluctuations of each interacting phase volume fraction throughout the flow period. Furthermore, the improved delayed detached-eddy simulation turbulence model is employed to resolve the flow features in and outside the wall boundary layer. From the findings, an improvement in flow performance was witnessed using guide vanes. Furthermore, three thin and non-contacting guide vanes were strategically positioned at the center and towards the circumference of the pipe within the bend area, causing an increase in flow efficiency by 78.87%. In addition, the guide vanes played a significant role in limiting turbulence effect to effective flow of the primary phase.

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Investigating the impact of velocity fluctuations and compressibility to aerodynamic efficiency of a fixed-wing aircraft

Cited by 10 publications

References 19 publications

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

Airflow Dynamics and Aluminum Coating Oxidation Behavior under Electric-Arc Spraying with Airflow Pulsations

Thermal-Hydraulic Analysis of Parabolic Trough Collectors Using Straight Conical Strip Inserts with Nanofluids

Improving flow efficiency in curved pipes during multi-phase, immiscible fluid flow using edge-tailored guide vanes

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