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Numerical Study on the Effect of Equivalence Ratio on Rotating Detonation Engine Flow field
Jacobs Somnic,Foluso Ladeinde 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
Rotating detonation engines (RDEs) have been extensively investigated recently as a candidate for an air-breathing propulsive system with high thermal efficiency, with most of the studies focusing on premixed combustion under stoichiometric conditions. Because a purely stoichiometric condition cannot be ascertained in realistic applications, the knowledge of the effects of equivalence ratio becomes very important. The present study has the objective of investigating the effects of equivalence ratio on premixed combustion in a realistic RDE system. For this purpose, both one-dimensional and two-dimensional spatial models are studied. The effects on the pressure, temperature, and chemical species distributions will be presented. A basic RDE is shown in Fig. 1. The combustion chamber is an annular ring, where the direction of flow is from the head end (bottom in figure) to the exit plane (top of figure). In experimental study, the fuel and oxidizer are injected separately into the combustion chamber to avoid backfire [2]. The mixing process occurs inside the combustion chamber while detonation wave propagates circumferentially to consume fresh reactive mixture. Schwer et al. [2] investigated the flow field of RDE in general and observed the effect of stagnation and back pressure on an RDE. In addition, Schwer et al.[3] also examined the fluid dynamics of rotating detonation engines with hydrogen and hydrocarbon fuels. Jin Zhou et al.[4] studied the effects of injection nozzle exit width on rotating detonation engine. These studies pertain to stoichiometric conditions. Only a handful of studies have investigated the effects of equivalent ratio. Wang et al.[5] recently investigated the effects of equivalence ratio and found that as the equivalence ratio increases, the velocity of the rotating detonation wave first increases and then decreases. Baoxing et al [6] experimentally studied the effects of equivalence ratio on RDE and found that for their engine model operating with equivalence ratio from 0.42 to 1.43, the rotating detonation wave was successfully initiated, and propagation self-sustained. In this study, we are interested to see how equivalence ratio influence RDE flow field in general. Furthermore, we want to see how it affects the detonation wave structure Key Words: Rotating Detonation Engine, Computational Fluid Dynamics (CFD), Supersonic Combustion, Equivalence Ratio.
The Girinya Dance Theatre of The Tiv People of Nigeria : an Aesthetic Evaluation
Jacob Manase Agaku 국립민속박물관 2008 International Journal of Intangible Heritage Vol.3 No.-
‘Residual theatre’ is used to refer to mean ritualperformances that are still enacted but which have losttheir original purpose. Such performances can still beenjoyed and can still play a role in promoting socialcohesion and a sense of identity, so long as the performers,and the audience, recognise and accept the way they havechanged. The Girinya dance of the Tiv people of Nogeria,which was originally a war dance, is a case in point. In theTiv dance aesthetic, men’s dances should be vigorous andenergetic, as the Girinya dance is, but whereas in the pastthe dance was about the way warriors should behave inbattle, it is now about continuity and renewal. I have tried todescribe and evaluate this aesthetic and the way it hasbeen adapted to have a new meaning within the changingculture of the Tiv people.
Comparison of RDE Simulation Methods
Jacobs Somnic,Foluso Ladeinde 한국추진공학회 2018 한국추진공학회 학술대회논문집 Vol.2018 No.12
Air-breathing Rotating Detonation Engine (RDE) has been widely investigated using a variety of techniques for the kinetic mechanism, turbulence, turbulence-combustion interaction, the spatial and temporal numerical procedure, and the use of Euler or the Navier-Stokes equations. However, there seems to be no consensus presently as to the optimal combination of procedures to use. In this work, a comparison of various modeling options is presented for the physics, chemistry, and numerical modeling of the RDE problem. Differing performance of several kinetic mechanisms has been observed and the two spatial numerical schemes investigated – the Weighted Essentially-Non-oscillatory (WENO) and MUSCL – give significantly different results. In this limited study, Euler and Navier-Stokes give results that are not significantly different, although the real issue in this case is the level of numerical dissipation, since no truly inviscid solutions to the flow equations are physically or numerically realizable. Other effects will be reported during the oral presentation.
Jacob Harris,Kevin Chorath,Eesha Balar,Katherine Xu,Anusha Naik,Alvaro Moreira,Karthik Rajasekaran 대한소아소화기영양학회 2022 Pediatric gastroenterology, hepatology & nutrition Vol.25 No.2
Purpose: While regurgitation is a common and often benign phenomenon in infants and younger children, it can also be a presenting symptom of gastroesophageal reflux disease (GERD). If untreated, GERD can lead to dangerous or lifelong complications. Clinical practice guidelines (CPGs) have been published to inform clinical diagnosis and management of pediatric GERD, but to date there has been no comprehensive review of guideline quality or methodological rigor. Methods: A systematic literature search was performed, and a total of eight CPGs pertaining to pediatric GERD were identified. These CPGs were evaluated using the Appraisal of Guidelines for Research and Evaluation instrument. Results: Three CPGs were found to be “high” quality, with 5 of 6 domains scoring >60%, one “average” quality, with 4 of 6 domains meeting that threshold, and the remaining four “low” quality. Conclusion: Areas of strength among the CPGs included “Scope and Purpose” and “Clarity and Presentation,” as they tended to be well-written and easily understood. Areas in need of improvement were “Stakeholder Involvement,” “Rigor of Development,” and “Applicability,” suggesting these CPGs may not be appropriate for all patients or providers. This analysis found that while strong CPGs pertaining to the diagnosis and treatment of pediatric GERD exist, many published guidelines lack methodological rigor and broad applicability.
Novel Wire-Guided Scalpel to Facilitate Central Venous Catheter Insertion without a Skin Bridge
Jacob Jeffrey Rauchwerger,Michael Serle,Jeffrey C. Astbury 대한혈관외과학회 2021 Vascular Specialist International Vol.37 No.3
Central venous catheter (CVC) placement is a commonly performed procedure. More than 5 million CVC placements are performed annually in the United States, with nearly 45% of critical care patients and 8% of all inpatients requiring a CVC during their hospitalization. A novel wire-guided scalpel (GuideBlade; Ambitus Medical Supplies LLC, Oceanside, NY, USA) has recently been introduced into clinical practice. In this communication, we will describe how to use the device and discuss possible advantages associated with its routine use during CVC placement.