다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Preface 1.General Considerations 2.Basic Processes in Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.Atomizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index

Atomization and Sprays

Camelina uses, genetics, genomics, production, and management

With the growing air transport demand and concerns about its environmental impacts, alternative jet fuels derived from non-conventional sources have become an important strategy for achieving a sustainable and green aviation. In the past 10 years, governments around the world along with aviation industry have invested significant efforts into exploring all sorts of alternative jet fuels that can be used to power aircraft engines. Among all the alternative jet fuels explored, the aviation sector has agreed that hydrocarbon-based ‘drop-in’ replacement fuels, which are fully interchangeable and compatible with current conventional jet fuels, would be the best choice in the near future, as they can be used without any modifications to today׳s aircraft or fuel infrastructure. This paper reviews the current state of development of ‘drop-in’ alternative jet fuels including various Fisher–Tropsch synthetic jet fuels and bio-jet fuels. Recent advances in research activities on alternative jet fuels, including fuel property evaluations, combustor component tests, engine tests, and flight tests, are highlighted. Furthermore, basic research needs for understanding the combustion characteristics of alternative jet fuels are underlined and discussed by reviewing recent fundamental combustion studies on ignition, extinction, flame propagation, emissions, and species evolution of various conventional and alternative jet fuels. Recognizing that the use of ‘simpler’ surrogate fuels to emulate the behavior of ‘complex’ alternative jet fuels is of fundamental and practical importance for the development of physics-based models to enable quantitative emissions and performance predictions using combustion modeling, recent studies on surrogate formulation for alternative jet fuels are also reviewed and discussed. This review concludes with a brief discussion of future research directions.

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Recent development in studies of alternative jet fuel combustion: Progress, challenges, and opportunities

Liquid jet in a subsonic gaseous crossflow: Recent progress and remaining challenges

Additive Manufacturing of Solid Rocket Propellant Grains

Analysis on the atomization characteristics of aviation biofuel discharging from simplex swirl atomizer

Breakup processes of pressure swirl spray in gaseous cross-flow

PREDICTION and control of pressure and pressure-rise rate during the ignition transient of solid-propellant rocket motors with a nonuniform port are of topical interest. In certain designs, an ignition pressure spike and a high rate of pressure rise may adversely affect the steadiness and stability of burning, thermoviscoelastic response of the grain and inhibitors, and the dynamic response of the hardware parts.1 An excessive pressurization rate can cause a failure even when the pressure is below the design limit.2,3 Although, a great deal of research has been done in the area of solid rocket motors (SRMs) for more than six decades, the accurate prediction of the ignition transient in ports of high-performance solid rocket, with sudden expansion and/or steep divergence/convergence or protrusions has not previously been accomplished.

Fluid-Throat-Induced Shock Waves During the Ignition Transient of Solid Rockets

Detailed theoretical and experimental studies on flame spread over nonuniform ports of solid propellant rockets have been carried out. An idealized two-dimensional laboratory motor was used for the experimental study with the aid of cinematography. A detailed numerical simulation of the flame spread has also been carried out with the help of a two-dimensional Navier-Stokes solver. Experimental results showing the phenomenon of secondary ignition have been reported earlier and also reviewed here with the inclusion of additional results of a three-dimensional geometry closer to a dual-thrust motor. In this paper more tangible results including the numerical modeling of flame spread have been reported. It has been shown conclusively that under certain conditions of step location, step height, and port height, which govern the velocity of gases at the step by the partially ignited propellant surface or by the igniter gas Row, secondary ignition can occur far downstream of the step, This is very likely to be within the recirculating Row region. The secondary ignition gives rise to two additional flame fronts, one of which spreads backward st a relatively lower velocity, presumably as a result of low reverse velocities present in the separation zone. This phenomenon is Likely to play an important role in the starting transient of solid propellant rockets with nonuniform ports.

B. N. Raghunandan

Papers

Additive Manufacturing of Solid Rocket Propellant Grains

Analysis on the atomization characteristics of aviation biofuel discharging from simplex swirl atomizer

Breakup processes of pressure swirl spray in gaseous cross-flow

Fluid-Throat-Induced Shock Waves During the Ignition Transient of Solid Rockets

Flame Spread with Sudden Expansions of Ports of Solid Propellant Rockets