DISTRIBUTION OF LIQUID AND FORMED VAPOUR IN UNHEATED AND HEATED TUBE WITH A HIGH VELOCITY AIR FLOW

Author(s):  
A.D. Rekin
Keyword(s):  
Air Flow ◽  
Author(s):  
Liming Dai ◽  
Lu Han

This study focuses on diagnosing the periodicity change of nonlinear dynamic responses of a fluttering plate excited by high-velocity air flow. The number and changing multiple-periodicities of the system with the implementation of Periodicity Ratio (PR) are investigated. The multiple-periodicity diagram is generated such that the periodicities and nonlinearity of the systems with respect to the system parameters can be graphically studied. The results of the research show that the number of period of periodicity of the systems increases when certain system parameters increase. Transitional characteristics of the systems are also investigated with Periodicity Change Rate as well.


1982 ◽  
Vol 104 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Ming-hua Cao ◽  
Hong-kun Jiang ◽  
Ju-shan Chin

An improved semiempirical analysis is presented for the liquid fuel distribution downstream of a plain orifice fuel injector under a cross-stream air flow of uniform high velocity and constant ambient temperature. The analysis is based on a simplified “flat-fan spray” model (ε–ψ model). A ε–ψ model is proposed which assumes that the fuel injected through the orifice forms a flat-fan liquid sheet with an average fan angle 2ψ0. Once the droplets have been formed, the trajectory of individual droplets determines the fuel distribution downstream. The validity of the analysis is confirmed by comparison of calculations based on the ε–ψ model and test data obtained from fuel distribution experiments under cross-stream air flow of ambient temperature. The agreement is shown to be very good. The semiempirical analysis presented offers a very useful approach in the preliminary design of the fan air flow path portion of turbofan afterburners.


Author(s):  
Gui Xiang Yang ◽  
J. S. Chin

An experimental study has been conducted on the effect of high back pressure on the spray characteristics of a plain jet injector under coaxial high velocity air flow. The air pressures tested range from 1 to 16 atm, the range of air velocity is 60–120 m/s, the pressure drops of injector tested are 200–2000 kpa. Working fluid is water. Injector hole diameter is 0.5 mm. The key feature of the experiment is using a convergent-divergent nozzle to maintain a high air pressure inthe test chamber and at the same time to maintain a high velocity air flow in the atomization zone. Such an experimental arrangement totally eliminates air and droplets recirculation in the test chamber and problem related to slow droplet settling in a commonly used pressurized vessel for high back pressure atomization research. The results show that SMD decreases monotonicly with the increase of back pressure or air velocity, at different air velocities, the effect of air pressure is different. The drop size distribution parameter N in Rosin-Rammler distribution decreases slightly with increase of back pressure or air velocity.


Author(s):  
Cao Ming-hua ◽  
Jiang Hong-kun ◽  
Chin Ju-shan

An improved semi-empirical analysis is presented for the liquid fuel distribution downstream of a plain orifice fuel injector under cross-stream airflow of uniform high velocity and constant ambient temperature. The analysis is based on a simplified “flat-fan spray” model (ε – ψ model). The ε – ψ model is proposed which assumes that the fuel injected through the orifice forms a flat-fan liquid sheet with an average fan angle 2 ψ0. Once the droplets have been formed, the trajectory of individual droplets determines the fuel distribution downstream. The validity of the analysis is confirmed by comparison of calculations based on the ε – ψ model and test data obtained from fuel distribution experiments under cross-stream air flow of ambient temperature. The agreement is shown to be very good. The semi-empirical analysis presented offers a very useful approach in the preliminary design of the fan air flow path portion of turbo-fan after-burners.


2014 ◽  
Vol 8 (5) ◽  
pp. 712-715 ◽  
Author(s):  
A. G. Egorov ◽  
A. S. Tizilov ◽  
V. Ya. Niyazov ◽  
V. A. Arkhipov ◽  
O. V. Matvienko
Keyword(s):  

Author(s):  
Az.A. Aliev ◽  
A.S. Burkov ◽  
V.A. Tovstonog ◽  
V.I. Tomak ◽  
D.A. Yagodnikov

One of the features of high-velocity atmospheric aircraft is the presence of thin aerofoils with edges characterised by a small blunt radius, subjected to high-temperature aerodynamic heating at temperatures of up to 2000 -- 2500 °C. In order to ensure correct operation of both the power plant producing thrust in such vehicles, assumed to be a supersonic combustion ramjet, and respective aerodynamic controls, the components subjected to high-velocity air flows must retain their geometric stability. A way to ensure their performance is to use methods and means of thermal protection, as well as materials that are resistant to high temperatures in an oxidising atmosphere, while one of the promising trends is employing refractory oxide materials such as oxides of aluminium, zirconium and hafnium. Since this class of materials has low thermal conductivity, large temperature gradients develop in the vicinity of the surface being heated, resulting in temperature stresses, all of which designers should take into account. We analysed the temperature state in a model of an acute zirconium oxide wedge featuring a small blunt radius, subjected to a high-velocity air flow. To reduce the edge temperature and temperature gradients, we propose a design solution implemented as a thermally conductive core lined with a thin layer of zirconium oxide. We consider using aluminium oxide and hafnium boride as core materials


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