scholarly journals Intensification of ultra-lean catalytic combustion of methane in microreactors by boundary layer interruptions- A computational study

2021 ◽  
pp. 116730
Author(s):  
Graeme Hunt ◽  
Nader Karimi ◽  
Amirfarhang Mehdiadeh
Drones ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 56
Author(s):  
José Serrano Cruz ◽  
Andrés Tiseira ◽  
Luis García-Cuevas ◽  
Pau Varela

Distributed electric propulsion and boundary layer ingestion are two attractive technologies to reduce the power consumption of fixed wing aircraft. Through careful distribution of the propulsive system elements, higher aerodynamic and propulsive efficiency can be achieved, as well as a lower risk of total loss of aircraft due to foreign object damage. When used on the wing, further reductions of the bending moment on the wing root can even lead to reductions of its structural weight, thus mitigating the expected increase of operating empty weight due to the extra components needed. While coupling these technologies in fixed-wing aircraft is being actively studied in the big aircraft segment, it is also an interesting approach for increasing the efficiency even for aircraft with maximum take-off masses as low as 25 kg, such as the A3 open subcategory for civil drones from EASA. This paper studies the effect of changing the propellers’ position in the aerodynamic performance parameters of a distributed electric propulsion with boundary layer ingestion system in a 25 kg fixed-wing aircraft, as well as in the performance of the propellers. The computational results show the trade-offs between the aerodynamic efficiency and the propeller efficiency when the vertical position is varied.


2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Yanfeng Zhang ◽  
Shuzhen Hu ◽  
Ali Mahallati ◽  
Xue-Feng Zhang ◽  
Edward Vlasic

This work, a continuation of a series of investigations on the aerodynamics of aggressive interturbine ducts (ITD), is aimed at providing detailed understanding of the flow physics and loss mechanisms in four different ITD geometries. A systematic experimental and computational study was carried out by varying duct outlet-to-inlet area ratios (ARs) and mean rise angles while keeping the duct length-to-inlet height ratio, Reynolds number, and inlet swirl constant in all four geometries. The flow structures within the ITDs were found to be dominated by the boundary layer separation and counter-rotating vortices in both the casing and hub regions. The duct mean rise angle determined the severity of adverse pressure gradient in the casing's first bend, whereas the duct AR mainly governed the second bend's static pressure rise. The combination of upstream wake flow and the first bend's adverse pressure gradient caused the boundary layer to separate and intensify the strength of counter-rotating vortices. At high mean rise angle, the separation became stronger at the casing's first bend and moved farther upstream. At high ARs, a two-dimensional separation appeared on the casing and resulted in increased loss. Pressure loss penalties increased significantly with increasing duct mean rise angle and AR.


2006 ◽  
Vol 45 (3) ◽  
pp. 1009-1013 ◽  
Author(s):  
Mario Iamarino ◽  
Paola Ammendola ◽  
Riccardo Chirone ◽  
Raffaele Pirone ◽  
Giovanna Ruoppolo ◽  
...  

2017 ◽  
Vol 41 ◽  
pp. 1-6 ◽  
Author(s):  
Fengxiang Liu ◽  
Yanyan Sang ◽  
Hongwei Ma ◽  
Zhanping Li ◽  
Zhiming Gao

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