scholarly journals Liquid Propane Injection in Flash-Boiling Conditions

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6257
Author(s):  
Łukasz Jan Kapusta ◽  
Jakub Bachanek ◽  
Changzhao Jiang ◽  
Jakub Piaszyk ◽  
Hongming Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Saturation Pressure ◽  
Injection Pressure ◽  
Spray Angle ◽  
Liquid Propane ◽  
Spray Tip Penetration ◽  
Commercial Gasoline ◽  
Flash Boiling ◽  
Set Up ◽  
The Impact

This study aimed to investigate the influence of flash-boiling conditions on liquid propane sprays formed by a multi-hole injector at various injection pressures. The focus was on spray structures, which were analysed qualitatively and quantitatively by means of spray-tip penetration and global spray angle. The effect of flash boiling was evaluated in terms of trends observed for subcooled conditions. Propane was injected by a commercial gasoline direct injector into a constant volume vessel filled with nitrogen at pressures from 0.1 MPa up to 6 MPa. The temperature of the injected liquid was kept constant. The evolution of the spray penetration was observed by a high-speed camera with a Schlieren set-up. The obtained results provided information on the spray evolution in both regimes, above and below the saturation pressure of the propane. Based on the experimental results, an attempt to calibrate a simulation model has been made. The main advantage of the study is that the effects of injection pressure on the formation of propane sprays were investigated for both subcooled and flash-boiling conditions. Moreover, the impact of the changing viscosity and surface tension was limited, as the temperature of the injected liquid was kept at the same level. The results showed that despite very different spray behaviours in the subcooled and flash-boiling regimes, leading to different spray structures and a spray collapse for strong flash boiling, the influence of injection pressure on propane sprays in terms of spray-tip penetration and spray angle is very similar for both conditions, subcooled and flash boiling. As for the numerical model, there were no single model settings to simulate the flashing sprays properly. Moreover, the spray collapse was not represented very well, making the simulation set-up more suitable for less superheated sprays.

Influence of Elevated Fuel Temperatures on the Spray Characteristics of Gasoline - Ethanol Blends

2021 ◽  
Author(s):  
Niranjan Miganakallu ◽  
Ashwin Karthik Purushothaman ◽  
William R. Atkinson ◽  
Nathan Peters ◽  
Tadeu Miguel Malago Amaral ◽  
...  
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Gasoline Direct Injection ◽  
Spray Angle ◽  
Fuel Injector ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Fuel Blends ◽  
Flash Boiling ◽  
Ethanol Blends

Abstract In this study, the effect of elevated fuel temperatures on the spray characteristics of gasoline-ethanol blends were studied in an optically accessible constant volume spray and combustion vessel. MAHLE SmartHeat® is a fuel heater located directly upstream of the fuel injector. High speed images of the spray injected from a six-hole gasoline direct injection injector typical of a side-injection engine were captured with shadowgraph imaging technique. Two fuel blends, gasoline with 10% ethanol (E10) and 85% ethanol (E85) were investigated at ambient conditions of 1 bar, 45°C and 4 bar, 180°C respectively at an injection pressure of 100 bar. Fuel temperatures were varied from 75 to 250°C. A comparison of the near nozzle and the global spray characteristics was made for the two fuels at those temperatures. Results showed that flash boiling leads to two primary effects for the two fuel blends: (i) an appreciable increase in spray angle near the exit of the nozzle followed by (ii) a decrease in spray angle downstream of the nozzle due to the interaction of the plumes and the collapsing of the spray. Furthermore, for both fuel blends, upon flash boiling, entrainment and mixing were reduced downstream of the nozzle because of the collapse of the spray. To reduce this effect, nozzle orientations and geometries should be modified.

scholarly journals Research on Blade-Casing Rub-Impact Mechanism by Experiment and Simulation in Aeroengines

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jie Hong ◽  
Tianrang Li ◽  
Zhichao Liang ◽  
Dayi Zhang ◽  
Yanhong Ma
Keyword(s):  
High Speed ◽  
High Performance ◽  
Element Model ◽  
Physical Parameters ◽  
Test Rig ◽  
Calculation Results ◽  
Rotor Support ◽  
Blade Tip ◽  
Set Up ◽  
The Impact

Aeroengines pursue high performance, and compressing blade-casing clearance has become one of the main ways to improve turbomachinery efficiency. Rub-impact faults occur frequently with clearance decreasing. A high-speed rotor-support-casing test rig was set up, and the mechanism tests of light and heavy rub-impact were carried out. A finite element model of the test rig was established, and the calculation results were in good agreement with the experimental results under both kinds of rub-impact conditions. Based on the actual blade-casing structure model, the effects of the major physical parameters including imbalance and material characteristics were investigated. During the rub-impact, the highest stress occurs at the blade tip first and then it is transmitted to the blade root. Deformation on the impact blade tip generates easily with decreased yield strength, and stress concentration at the blade tip occurs obviously with weaker stiffness. The agreement of the computation results with the experimental data indicates the method could be used to estimate rub-impact characteristics and is effective in design and analyses process.

Experimental Investigation of the Development of Cavitation in a Squeeze Film Damper

2010 ◽  
Author(s):  
Changhu Xing ◽  
Frank Horvat ◽  
Stefan Moldovan ◽  
Minel J. Braun
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Leaf Shape ◽  
Saturation Pressure ◽  
Angular Speed ◽  
Squeeze Film ◽  
Pressure Curve ◽  
Large Area ◽  
Squeeze Film Damper ◽  
Set Up

When cavitation takes place in the squeeze film damper (SFD), its types and extent affect the performance of the SFD significantly. Thus, a fundamental understanding of the incipience, formation and evolution of this phenomenon becomes important both for predicting the dynamic properties of the damper and for the practitioner designers. A test rig was set up to investigate the formation of the cavitation bubbles during the process of a steady-state operation. By adopting a crankshaft configuration, the SFD journal orbit can be fixed at a specified eccentricity. The journal position and its eccentricity are tracked by means of Bently proximity sensors. When cavitation takes place, its shape and evolution are recorded by a Photron APX-RS high speed camera. With the Dow Corning 200 lubricant, the gaseous bubbles form in a fern-leaf shape even at low whirling speed. The bubbles evolve to a miniature flattened shape and as the angular speed increases, the gaseous cavitation gives way or is joined by vaporous cavitation. With a further increase of whirling speed, the vaporous bubbles can be clearly seen to occupy a large area. The evolution of the cavitation can be explained by the Sommerfeld pressure curve as it relates to the gaseous and vaporous saturation pressure. The experimental results confirm the assumption made by these authors in the previous numerical simulations for the homogeneous cavitation models.

scholarly journals Spray Characteristics at Preheating Temperatur of Diesel-Biodiesel-Gasoline Fuel Blend

2021 ◽  
Vol 5 (2) ◽  
pp. 134
Author(s):  
Moch Miftahul Arifin ◽  
Nasrul Ilminnafik ◽  
Muh. Nurkoyim Kustanto ◽  
Agus Triono
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Fuel Mixture ◽  
Spray Angle ◽  
Injection System ◽  
Spray Characteristics ◽  
Fuel Blend ◽  
Spray Tip Penetration

Technological developments in diesel engines require improvements to the fuel injection system to meet the criteria for economical, high-power and efficient combustion and meet environmental regulatory standards. One method that has a lot of interest is changing the characteristics of the fuel, with the aim of producing optimal combustion. Spray characteristics have a big role in determining the quality of combustion in diesel engines. A good spray can improve the quality of fuel atomization and the homogeneity of the air-fuel mixture in the combustion chamber so that it can produce good engine performance and low emissions. This study aims to determine the effect of a diesel-biodiesel (Calophyllum inophyllum)-gasoline blendandfuel heating on the spray characteristics. The research was conducted with variations in composition (B0, B100, B30, B30G5 and B30G10) and fuel heating (40, 60, 80, and 100 °C). Fuel injected atapressure of 17 MPa in to a pressure chamber of 3 bar. The spray formed was recorded with a high-speed camera of 480 fps (resolution 224x168 pixel). In B100 biodiesel, the highest viscosity and density cause high spray tip penetration, small spray angle, and high spray velocity. The addition of diesel oil, gasoline, and heating fuel reduces the viscosity and density so that the spray tip penetration decreases, the spray angle increases and the velocity of spray decreases.

Stereographic Backlit Imaging and Bubble Identification From a Plunging Jet With Floor Interactions

2021 ◽  
Author(s):  
Roy A. Pillers ◽  
Theodore J. Heindel
Keyword(s):  
High Speed ◽  
Imaging Techniques ◽  
Primary Source ◽  
Breaking Waves ◽  
Bubble Plume ◽  
Shape Estimation ◽  
Fish Farms ◽  
Automated Identification ◽  
Set Up ◽  
The Impact

Abstract Plunging jets have been extensively studied for their relatively simple set-up but complex multiphase interactions. This phenomenon includes gas carry-under and mixing, which occurs when shear effects between the plunging liquid jet and surrounding gas are sufficient to entrain gas at the impact site. Previous investigations typically assume the floor has an infinite depth and neglect compressive effects caused by the jet interacting with the catch tank floor. While this assumption is ideal for breaking waves in the middle of the ocean, many other applications have to contend with floor effects. These include waterfalls, wastewater treatment, dams, fish farms, mineral separation, and molten metal pouring. It is hypothesized that floor interactions will significantly affect the multiphase flow hydrodynamics, especially in places where the uninhibited jet would approach or pass the floor region. Using a large catch tank with an adjustable floor region designed to hold a constant water level, data were collected using high-speed backlit stereographic imaging to capture and compare the effects of three separate tank depths with those found using an infinite pool assumption. To identify bubbles in each stereographic projection, a uniform bubble recognition procedure was developed that was used across all data sets. This allowed for the automated identification of bubble entrainment regions, which could be compared with different flow conditions. Preliminary results are inconclusive as to the effects of the floor region on the bubble plume dynamics; however, the results showed consistent measurements between trials and the two stereographic cameras, implying the time variation of the jet dynamics was the primary source of uncertainty in the results and not the identification procedure. Therefore, the identification methods have provided a method for plume volume and shape estimation, which will be used in future studies using 3D imaging techniques.

Analysis of Dynamic Response of Simply-Supported Girder Bridge in High-Speed Railway Based on the Moving Rows Mass-Spring Model

2012 ◽  
Vol 193-194 ◽  
pp. 919-924
Author(s):  
Jin Feng Wu ◽  
Zhi Jun Zhang ◽  
Xiao Zhen Li
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Spring Model ◽  
Simply Supported ◽  
Mass Spring Model ◽  
Girder Bridge ◽  
Set Up ◽  
Mass Spring ◽  
The Impact ◽  
Bridge System

The vibration theory of beam and D’Alembert principle are used to set up vehicle-bridge system for a simply-supported girder bridge under the moving rows mass-spring model. The kinematic equations of vehicle and bridge are derived separately. And with the force balanced relationship and the displacement compatibility conditions between wheels and rail, the equations of vehicle-bridge system are established. A calculating program is complicated with MATLAB language and solved by Newmark-β method. Results show that the effect of the damping ratio on the impact factor is significant and running speed of the vehicle is one of the main actors resulting in vibration of the system.

Experimental Investigation of Water Entry Impact on Hydrophobic Surfaces

2015 ◽  
Author(s):  
Bulent Guzel ◽  
Fatih C. Korkmaz
Keyword(s):  
Experimental Investigation ◽  
Flow Separation ◽  
High Speed ◽  
Water Entry ◽  
Air Entrapment ◽  
Hydrophobic Surfaces ◽  
Blunt Bodies ◽  
Drop Tests ◽  
Set Up ◽  
The Impact

The results of an experimental investigation on hull bottom slamming of three different geometries, sphere, cylinder and wedge, with hydrophobic surfaces are presented. In water entry of blunt bodies, different fluid dynamics phenomena like jet formation, cavity formation, water splashing, flow separation on solid surfaces and air entrapment between solid and liquid surface have been studied for decades. Our study is aimed at understanding and modeling the dynamics of slamming under an extended range of parameters including hydrophobic surfaces. In this study, drop tests have been set up for hull bottom slamming by dropping a body from various heights toward water surface. From digital images captured using a high speed camera, flow separation and water splashing at different velocities are observed and spreading diameters and entrance characteristics are measured during the impact process. At the same time, we measure the pressure distribution on the surface of the bodies during impact via strain gages.

Spray Tip Penetration of Inversed-delta Injection Rate Shaping in Non-Vapourising Condition

2019 ◽  
Vol 16 (3) ◽  
pp. 7048-7060
Author(s):  
M. F. E. Abdullah ◽  
Y. Toyama ◽  
S. Saruwatari ◽  
S. Akiyama ◽  
T. Shimada ◽  
...  
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Injection Rate ◽  
Diesel Spray ◽  
Spray Tip Penetration ◽  
Mems Sensor ◽  
Fuel Delivery ◽  
Rate Shaping ◽  
Constant Volume Combustion Chamber ◽  
Performance And Emissions

The performance and emissions of diesel engine are highly depending on the fuel delivery process thus, injection rate shaping approach is expected to be crucial in the development of a highly efficient and clean modern engine. A novel rate shaping injector called TAIZAC (TAndem Injection Zapping ACtivation) is used to realise an injection rate shaping of progressive ramp-down of high initial injection pressure as in inversed-delta shape. This study aims to investigate diesel spray tip penetration behaviour in inverseddelta injection rate shaping. The experiments are conducted under a high-density nonvapourising condition in a constant volume combustion chamber. High-speed diffused back illumination DBI imaging of the diesel spray is acquired at 30,000 fps using mercury lamp as the light source. The tip penetration of the inversed-delta injection is smaller than that of rectangle injection regardless of their injection momentum which is proportional to t0.5 and t0.43 in rectangle and inversed-delta injection case, respectively. To examine the potential of inversed-delta injection on wall heat loss reduction, diesel spray flame impinges to a MEMS sensor located at 28-mm downstream. It is interesting to note that the heat flux in 200 MPa inversed-delta injection is reduced by approximately 15% compared to 200 MPa rectangle injection even though their tip penetration starts to diverge at approximately 30 mm; indicates the TAIZAC injector potential in improving engine thermal efficiency.

Numerical Study on High-Speed Impact Between a Water Droplet and a Deformable Solid Surface

2012 ◽  
Author(s):  
Yongqiang Han ◽  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Solid Surface ◽  
Water Droplet ◽  
High Speed ◽  
Numerical Study ◽  
Contact Radius ◽  
Deformable Solid ◽  
Theoretical Predictions ◽  
Steam Turbine Blade ◽  
Set Up ◽  
The Impact

In this study an axisymmetric model is set up to study the impact of a spherical water droplet with a planar deformable solid surface using the Lagrange-Euler coupling method which is based on a penalty formulation. The diameter and velocity of the droplet are 0.4 mm and 500 m/s respectively, while the solid is a kind of steam turbine blade material. The generated pressure distribution in the droplet and its variation with time, the formation of lateral jet, the deformation and stress distribution in the solid are obtained and investigated. It is shown that the compressibility of the droplet and the solid plays a significant role during the impact. The water-hammer pressure and the maximum contact edge pressure are calculated and in good agreement with the existing theoretical predictions. The calculated contact radius for shock departure is larger than that of the conventional theoretical prediction, which is analyzed and attributable to the radial motion of the liquid in the compressed region. The formation of the high-speed lateral jet is calculated and the time for the observable jetting is much later than that of the shock departure. This delay is discussed and the reason needs more research. The pressure of the contact edge region remains highest even after a considerable time of shock departure and lateral jetting. In the mean time, a saucer-shaped depression is generated in the center of the impact. The stress waves in solid move faster even before shock departure in the liquid. This causes disturbance of the solid surface before the high-speed lateral jetting and provides site for the scouring action of it, and subsequently may cause material damage and erosion.

Vibration Tests of the Processing Shaft Cascading Structure in High Speed and High Precision PCB Drilling Machine

2012 ◽  
Vol 246-247 ◽  
pp. 1263-1267
Author(s):  
Feng Gong ◽  
Yan Ping Tan ◽  
Ji Bin Li
Keyword(s):  
High Precision ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Drilling Machine ◽  
Guide Rail ◽  
Basic Part ◽  
Free Mode ◽  
Set Up ◽  
Vibration Tests ◽  
The Impact

It is necessary to study the dynamic characteristics of the structure of processing shaft cascade in high speed and high precision PCB drilling machine because of its great impact on the drilling precision. As a basic part, the dynamic characteristics of the structure of cascade depend on the dynamic characteristics of the Z-axis floor. Based on it, firstly, the free mode test is conducted on the Z-axis floor, the same as the modes that it is just set up on the guide rail, the cascade is added and the motor spindle has been added on the Z-axis floor. From the four situations, the modal pa-rameters are gained in the tests. Then the ODS test is carried out and the vibration is analyzed in the real situation. The vibration tests of the cascade comprehensively acquire dynamic characteristics from the Z-axis floor before being assembled to the Z-axis floor which is entirely cascaded on the Z axis. Acknowledge of the impact that the vibrations bring to the drilling precision of the drilling machine provides the direction of improving the structure.

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