10.1063/5.0070212.2
0
Citation
0
Reference
10
Related Paper
Abstract:
The impact of droplets at increased environmental pressure is important in many industrial applications. Previous studies mainly considered the impact process at standard or reduced environmental pressure, and the effect of high environmental pressure is unclear. In this study, we experimentally investigate the impact of ethanol droplets on dry smooth surfaces at increased environmental pressure. The effects of the environmental pressure on the splashing and rupture of the crown during the impact process are analyzed. The results show that surrounding gas with high environmental pressure can lead to the splashing of the crown in a “thread rupture” mode and the sizes of the secondary droplets from the rim of the liquid crown increase with the environmental pressure. The threshold for the transition from spreading to splashing during the impact process is obtained based on the theory of aerodynamics analysis of the lamella. At increased environmental pressure, the threshold speed of the impact decreases with increasing the environmental pressure because the wedge of the lamella is prevented from moving forward and is driven to detach from the substrate by the air ahead, which has a higher density due to the higher environmental pressure.Keywords:
Lamella (surface anatomy)
Ambient pressure
Impact pressure
Abstract The high mechanical strength of the lamellar Ti-6Al-4V extruded rod was characterized. The grain morphology of the extruded Ti-6Al-4V rod was investigated by optical microscopy. The microstructure of Ti-6Al-4V alloy consists of very fine α lamella of approximately 2.5 µ m in thickness and β lamella with 1 µ m thickness. Besides, a numerical model has been presented that reproduces the morphology of the lamellar colonies. In particular, the representative volume element with 512 elements, 4096 elements and, 32768 elements are studied with the C3D8 linear element. Experimental and numerical comparisons of the lamellae morphology have been presented.
Lamella (surface anatomy)
Morphology
Titanium alloy
Cite
Citations (0)
Lamella (surface anatomy)
Cite
Citations (8)
Lamella (surface anatomy)
Rod
Morphology
Cite
Citations (9)
Lamella (surface anatomy)
Elasticity
Collagen fibril
Cite
Citations (41)
Self-resonant cavitating jet is a kind of modulated jet with significant impact pressure fluctuations and cavitation effects. For the purpose of understanding the relationship between the effects of parameters and the erosion quantities of aluminum specimen impinged by cavitating jet, which was produced by a self-oscillating organ pipe nozzle of 1.0 mm in diameter, experiments were conducted in the High Pressure Vessels. The effect of working parameters on the erosion performance of the self-oscillating cavitating jet under ambient pressure was investigated, such as, jet pressure, ambient pressure, stand-off distance and exposure time. The obtained data show that the erosion quantity is positive proportional to the pressure drop, and the optimal results can be got for the stand-off distance and ambient pressure, which are 5~7 times of nozzle diameter and 2 MPa under the present experiment condition. The erosion quantities of self-oscillating cavitating jet are 1~2 times of common round jets under the same conditions, which could provide necessary tools in practical application, such as increasing drilling footages and drilling speed etc.
Ambient pressure
Impact pressure
Water jet
Cavitation Erosion
Pressure measurement
Cite
Citations (2)
Despite the important role of foams in industrial applications, few methods for determining the stability are present. By extending the existing light reflection-based apparatus, additional information about a single foam lamella can be obtained. Evaluation of these data delivers insight into the thinning process of the lamella. The potential of this technique is shown for the analysis of two surfactants with different head group lengths (Lutensol XP 100 and Lutensol XP 140).
Lamella (surface anatomy)
Reflection
Light reflection
Cite
Citations (0)
Lamella (surface anatomy)
Middle lamella
Cite
Citations (14)
The droplet size distribution,spray intensity,droplet momentum and droplet distribution mode are key factors that directly influence the fire-extinguishing efficiency of water mist system.This paper researches the effects of ambient pressure on flow coefficient of water mist nozzle and droplets spatial distribution,based on investigating the characteristics of a swirl solid-cone and hollow-cone nozzle under different ambient pressure conditions.The results show that the smaller the ambient pressure is,the denser the droplets will be at the edge area of the spray cone,i.e.,few droplets tend to center area within the spray cone when ambient pressure reduced.However,there is no obvious effect of ambient pressure on flow coefficient of water mist nozzle.
Mist
Ambient pressure
Spray characteristics
Discharge coefficient
Impact pressure
Pressure coefficient
Cite
Citations (1)
Ambient pressure
Dimensionless quantity
Impact pressure
Pulse pressure
Cite
Citations (7)
In this paper, a combined theoretical and numerical analysis is performed to study the internal and external flowfields of a liquid swirl injector. The effect of ambient pressure on the injector dynamics is explored systematically over a range of 1-50 atm. An increase in the ambient pressure increases the liquid film thickness, but decreases the spreading angle. This phenomenon can be attributed to the modification of the velocity profiles within the liquid film near the gas-liquid interface due to the alteration of the gas-phase shear stresses with pressure. The friction force at the interface plays a minor role. The generation and existence of stationary waves in the injector nozzle is also considered. At a higher ambient pressure, the pressure drop across the liquid sheet downstream of the injector exit increases, thereby suppressing the spreading of the liquid sheet. This in turn increases the thickness of the liquid sheet, and subsequently increases the breakup length at higher pressure. A semi-empirical model is developed to relate the velocity and pressure distributions near the surface of the liquid sheet. Good agreement is achieved between the measured and predicted shape and spreading angle of the liquid sheet.
Ambient pressure
Impact pressure
Sauter mean diameter
Weber number
Cite
Citations (39)