The Influence of Cylindrical Spray Chamber Geometry on the Evolution of High Pressure Diesel Sprays

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Dung Nguyen ◽  
Damon Honnery
Keyword(s):  
Threshold Value ◽  
Chamber Pressure ◽  
Spray Chamber ◽  
Combustion Chambers ◽  
Diesel Sprays ◽  
Spray Structure ◽  
Constant Volume Chamber ◽  
Illumination Method ◽  
Internal Chamber ◽  
Injection Pressures

While much is known on the effect of combustion chamber geometry on spray evolution in engines, less is known about its role in laboratory combustion chambers. This paper reports on a study, which investigates the effect of internal chamber geometry on the penetration and spreading angle of common rail nonreacting diesel sprays at room temperature conditions in a cylindrical constant volume chamber. This chamber has dimensions similar to those used in the literature. Spray chamber geometry was modified to yield three different chamber height-to-diameter ratios and two different nozzle stand-off distances. Sprays from three nozzles, two single-hole nozzles with different diameter and one twin-hole nozzle (THN), were examined for two injection pressures of 100 MPa and 150 MPa into two chamber pressures of 0.1 MPa and 5 MPa. To characterize the spray structure, a volume illumination method was used to study the spray tip penetration/speed and spread angle. For both injection pressures used with chamber pressure of 5 MPa, little sensitivity to vessel geometry was found in penetration distance and tip speed for variation in height to diameter ratio from 0.6 to 2.6 and variation in nozzle stand-off distance from 2 mm to 54 mm. For atmospheric chamber pressure, sensitivity to chamber geometry was evident and found to vary with nozzle type. Spread angle was found more largely affected by the calculation method and very sensitive to the image intensity threshold value for the cases investigated.

Experimental Study of Superheated Kerosene Jet Fuel Sprays From a Pressure-Swirl Nozzle

2017 ◽  
Author(s):  
Shaji S. Manipurath
Keyword(s):  
Laser Sheet ◽  
Cone Angle ◽  
Test Facility ◽  
Chamber Pressure ◽  
Engine Fuel ◽  
Fuel Temperature ◽  
Solid Cone ◽  
Spray Cone ◽  
Spray Structure ◽  
Pressure Swirl

The development of higher thermal stability fuels and the development of onboard fuel deoxygenation systems may permit the preheating of fuel up to about 755 K before the onset of pyrolysis. At a sufficiently high fuel temperature for a given combustion chamber pressure, the flash vaporization of liquid or supercritical state fuel can ensue upon injection into the chamber. The performance of standard aviation turbine engine fuel nozzles, designed for mechanically breaking up liquid sprays, may thus be significantly altered by the employment of severely preheated fuel. An evaluation of heated and superheated Jet A-1 sprays from a pressure-swirl atomizer was implemented in a purpose-built test facility. Laser sheet imaging of the spray yielded simultaneous axial cross-sectional maps of Mie-scatter and fluorescence signals. In addition, particle image velocimetry was also used to measure the spray droplet velocity-field. The results indicated that increasing the fuel’s dimensionless level of superheat ΔT* from −1.8 to 0.6 yielded significant changes in the spray structure; specifically, finer droplet sizes, a more uniform dropsize distribution across the spray, increased spray cone angle till about ΔT* = −0.8 followed by a contraction thereafter, marginally increased spray penetration, and significantly higher localised near nozzle tip droplet velocities. The measurements supported the hypothesis that the initial hollow-cone spray structure evolves to a near solid-cone structure with a central vapour core as the fuel is superheated.

The Effect of Chamber Pressure on the Thermal Performance of New Refrigerant R513a During Spray Cooling

2019 ◽  
Author(s):  
Nabeel M. Abdulrazzaq ◽  
Azzam S. Salman ◽  
Noble Anumbe ◽  
Amitav Tikadar ◽  
Saad K. Oudah ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Closed Loop ◽  
Cooling System ◽  
Heated Surface ◽  
Saturation Temperature ◽  
Spray Cooling ◽  
Copper Surface ◽  
Chamber Pressure ◽  
Refrigeration System ◽  
Spray Chamber

Abstract In this paper, the performance of a new low-GWP refrigerant R513a was experimentally investigated, during spray cooling. A spray cooling system was designed to work as a sub-system within a closed-loop refrigeration system. The influence of chamber pressure on heat flux and heat transfer coefficient were experimentally investigated. A smooth plain copper surface heated by a cartridge heater was cooled by the refrigerant (R513a) while flowing through a nozzle in the spray chamber. The results showed that chamber pressure has a significant impact on the overall thermal performance of the spray cooling operation. It was also determined that higher chamber pressures resulted in higher thermal performance. The highest chamber pressure attained in this study was 0.6 MPa. Furthermore, the surface temperature of the heated surface increased due to the increase of the saturation temperature of the liquid over the surface.

scholarly journals A RECENT EULERIAN–LAGRANGIAN CFD METHODOLOGY FOR MODELING DIRECT INJECTION DIESEL SPRAYS

2014 ◽  
Vol 11 (03) ◽  
pp. 1343012 ◽  
Author(s):  
JOSÉ M. DESANTES ◽  
SERGIO HOYAS ◽  
ANTONIO GIL ◽  
KHUONG ANH DUNG ◽  
FRÉDÉRIC RAVET
Keyword(s):  
Ambient Temperature ◽  
Direct Injection ◽  
Cone Angle ◽  
Chamber Pressure ◽  
Effective Diameter ◽  
Diesel Sprays ◽  
Spray Formation ◽  
Cold Starting ◽  
Starting Conditions ◽  
Good Agreement

The global objective of this work is to show the capabilities of the Eulerian–Lagrangian spray atomization (ELSA) model for the simulation of Diesel sprays in cold starting conditions. Our main topic is to focus in the analysis of spray formation and its evolution at low temperature 255 K (-18°C) and nonevaporative conditions. Spray behavior and several macroscopic properties, included the liquid spray penetration, and cone angle are also characterized. This study has been carried out using different ambient temperature and chamber pressure conditions. Additionally, the variations of several technical quantities, as the area coefficient and effective diameter are also studied. The results are compared with the latest experimental results in this field obtained in our institute. In the meantime, we also compare with the normal ambient temperature at 298 K (25°C) where the numerical validation of the model has shown a good agreement.

Microstructure and Ablation Behavior of Very Low-Pressure Plasma Sprayed ZrB2-Based Coatings

2021 ◽  
Author(s):  
Di Wang ◽  
Xiao-Tao Luo ◽  
Chang-Jiu Li
Keyword(s):  
Plasma Spraying ◽  
Ablation Rate ◽  
Low Pressure ◽  
Chamber Pressure ◽  
Spray Chamber ◽  
Deposition Pressure ◽  
Pressure Plasma ◽  
Low Pressure Plasma ◽  
Plasma Sprayed ◽  
Low Pressure Plasma Spraying

Abstract The effect of deposition pressure on the microstructure and ablation behavior of ZrB2 coatings deposited by very low pressure plasma spraying is investigated. The results show that under a chamber pressure less than 50 kPa, as the spray chamber pressure decreases, the porosity of the coating deposited at the same distance decreases, and the coating prepared under 100 Pa presents the lowest porosity of 1.79 %. Furthermore, among the ZrB2 coatings deposited at 100 Pa, 5 kPa, 10 kPa and 50 kPa, the dense coating deposited at 100 Pa showed the lowest ablation rate of 0.33 μm/s, 0.75±0.08 mg/s.

scholarly journals Biodiesel production from Cynara cardunculus L. and Brassica carinata A. Braun seeds and their suitability as fuels in compression ignition engines

2016 ◽  
Vol 10 (1s) ◽  
pp. 47 ◽  
Author(s):  
Stefania De Domenico ◽  
Luciano Strafella ◽  
Leone D’Amico ◽  
Marcello Mastrorilli ◽  
Antonio Ficarella ◽  
...  
Keyword(s):  
Brassica Carinata ◽  
Constant Volume ◽  
Environmental Benefits ◽  
Biodiesel Production ◽  
Injection System ◽  
Chamber Pressure ◽  
Compression Ignition ◽  
Cynara Cardunculus ◽  
Compression Ignition Engines ◽  
Constant Volume Chamber

The development of energy crops can provide environmental benefits and may represent an opportunity to improve agriculture in areas considered <em>at low productivity</em>. In this work, we studied the energy potential of two species (<em>Brassica carinata</em> A. Braun and <em>Cynara cardunculus</em> L.) and their seed oil productivity under different growth conditions. Furthermore, the biodiesel from the oil extracted from the seeds of these species was produced and analysed in term of utilisation as fuels in compression ignition engines. In particular, the spray penetration and shape ratio were measured in a constant-volume chamber and compared with the results obtained with a standard diesel fuel. These results were obtained using a standard common rail injection system at different injection pressure, injection duration, and constant-volume chamber pressure.

Influence of Spray Velocity and Structure on the Air Entrainment in the Primary Breakup Zone of High Pressure Diesel Sprays

2002 ◽  
Author(s):  
Christian Schugger ◽  
Ulrich Renz
Keyword(s):  
High Pressure ◽  
Momentum Transfer ◽  
Scattered Light ◽  
Injection Pressure ◽  
Air Entrainment ◽  
Turbulent Dispersion ◽  
Nozzle Geometry ◽  
Diesel Sprays ◽  
Spray Structure ◽  
Primary Breakup

Nozzle geometry and rail pressure influence the gas-liquid momentum transfer and the turbulent dispersion in the primary breakup zone of high-pressure Diesel sprays, and consequently the combustion processes. To investigate these phenomena, different measuring techniques have been used. The spray structure is visualized using shadowgraphy and scattered light imaging, and the axial velocities in the dense spray region have been measured using a Laser Correlation Velocimeter. Gas velocities are measured using Particle Image Velocimetry. It is found that the dimensionless velocities (related to the frictionless velocity) are independent of the injection pressure and the nozzle geometry. However the momentum transfer between the liquid phase and the surrounding air strongly depends on the spray structure. Here a sharp edged nozzle inlet promotes cavitation and turbulence levels in the nozzle which leads to stronger breakup and significantly enhanced air entrainment.

Sign in / Sign up

Export Citation Format

Share Document