Droplet Vaporization in a High-Pressure Gas

1993 ◽  
Vol 115 (3) ◽  
pp. 699-706 ◽  
Author(s):  
J. P. Hartfield ◽  
P. V. Farrell
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Life Time ◽  
Free Fall ◽  
Video Camera ◽  
Vaporization Rate ◽  
Gas Temperature ◽  
Droplet Vaporization ◽  
Ambient Gas ◽  
Temperature And Pressure

Evaporation of single, liquid droplets in a high-temperature, high-pressure gaseous environment has been investigated experimentally. The effects of gas temperature, pressure, and strength of naturally occurring convective flows were studied. Pure hydrocarbon (n-heptane) and trichlorotrifluoroethane (R-113) droplets were vaporized in a nitrogen atmosphere within a sealed chamber, which was developed to minimize forced convection. Experiments were carried out in normal and microgravity (~ 10−5 g) fields in order to examine the effect of natural convection. A single droplet was attached to the end of a quartz fiber. The gas temperature and pressure were raised quickly by a compressive process. The gas temperature and pressure were varied from 0.93<Tr<1.23 and 0.32<Pr<0.73. The droplet was located at the point of compressive symmetry. Droplet lifetime and instantaneous vaporization rate were determined from the data recorded by video camera. The results indicated that ambient gas temperature is a more significant parameter than ambient pressure for high-pressure droplet vaporization. This conclusion was based on comparisons of droplet vaporization rate for the range of temperatures and pressure tested. Ambient gas pressure was seen to have a weaker influence on vaporization rate. Removal of the gravity field during free-fall experiments resulted in an increase of droplet life time of about 30 percent for the case of R-113 liquid, and little change for the n-heptane droplets.

scholarly journals A Review Paper on Simulation and Modeling of Combustion Characteristics under High Ambient and High Injection of Biodiesel Combustion

2015 ◽  
Vol 773-774 ◽  
pp. 580-584
Author(s):  
Adiba Rhaodah Andsaler ◽  
Amir Khalid ◽  
Him Ramsy ◽  
Norrizam Jaat
Keyword(s):  
Cfd Simulation ◽  
Ambient Pressure ◽  
Combustion Characteristics ◽  
Spray Angle ◽  
Effect Of Temperature ◽  
Gas Temperature ◽  
Common Rail System ◽  
High Injection ◽  
Air Mixing ◽  
Temperature And Pressure

This paper describes simulation of combustion characteristics under high ambient and high injection of biodiesel combustion by using CFD simulation. Diesel engine performance and emissions is strongly couple with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of spray pattern, liquid length and vapor penetration. The method of the simulation of real phenomenon of diesel combustion with optical access rapid compression machine is also reviewed and experimental results are presented. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapor phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing. All of the experiments will be conducted and run by using CFD. The simulation will show in the form of images.

Energies of the phases of ice at low temperature and pressure relative to ice Ih

1988 ◽  
Vol 66 (4) ◽  
pp. 919-924 ◽  
Author(s):  
Y. Paul Handa ◽  
D. D. Klug ◽  
Edward Whalley
Keyword(s):  
High Pressure ◽  
Heat Flow ◽  
Low Temperature ◽  
Ambient Pressure ◽  
High Pressure Phase ◽  
Flow Calorimeter ◽  
Heat Flow Calorimeter ◽  
Temperature And Pressure ◽  
Pressure Phase

The enthalpy of transformation to ice Ic of ice II, IX, V, VI, and VIII that have been recovered at 77 K and ambient pressure, and of the transformation of ice Ic to Ih, has been measured in a heat-flow calorimeter. The enthalpy of transformation of ice Ic to Ih depends on the high-pressure phase used to make the ice Ic. The thermodynamics of the transformation of ice IX, which was made by cooling ice III at 0.3–0.7 K s−1, to ice III shows that the ice IX was fully orientationally ordered to the precision of the experiments.

scholarly journals Effects of Temperature and Ambient Pressure on Spray Characteristics of Biodiesel Combustion

2015 ◽  
Vol 773-774 ◽  
pp. 501-505 ◽  
Author(s):  
Mohamad Jaat ◽  
Amir Khalid ◽  
Azwan Sapit ◽  
Siti Mariam Basharie ◽  
Adiba Rhaodah Andsaler ◽  
...  
Keyword(s):  
Diesel Fuel ◽  
Diesel Engines ◽  
Ambient Pressure ◽  
Spray Angle ◽  
Effect Of Temperature ◽  
Ignition Process ◽  
Gas Temperature ◽  
Common Rail System ◽  
Spray Characteristics ◽  
Temperature And Pressure

s: Diesel fuel injection is the most dominant in ignition process of the diesel engines combustion. Diesel engines have been widely used in heavy-duty and light-duty vehicles due to their higher fuel economy, efficient and powerful than spark ignition (SI) engines. The principal objective of this research is to seek the effect of temperature and pressure on the spray characteristics, as well as fuel-air mixing characteristics. Experiments were performed in a constant volume chamber at specified ambient gas temperature and pressure. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to clarify the real images of mixture formation such as spray penetration, fuel evaporation and spray interference. The liquid phase of the spray reaches a maximum penetration distance soon after the start of injection, while the vapour phase of the spray continues to penetrate downstream. The condition to which the fuel is affected was estimated by combining information on the wall chamber temperature, ambient temperature and photographs of the spray. The increases in ambient pressure inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air premixing.

The Effect of Ambient Gas Temperature and Density on the Development and Wall Impingement of High-Injection-Pressure Diesel Fuel Sprays

1993 ◽  
Vol 115 (4) ◽  
pp. 777-780 ◽  
Author(s):  
Gong Yunyi ◽  
Liang Xuanming
Keyword(s):  
High Pressure ◽  
Ambient Temperature ◽  
Diesel Fuel ◽  
Injection Pressure ◽  
Spray Angle ◽  
Gas Temperature ◽  
High Injection ◽  
High Injection Pressure ◽  
Wall Impingement ◽  
Ambient Gas

An investigation of the effect of ambient gas temperature and density on diesel fuel spray penetration, spray angle, and wall impingement at an injection pressure of 75–134 MPa was conducted in a constant-volume bomb with a reconstructed Cummins PT fuel system by using a high-speed photographic technique. The results show that penetration does not increase monotonically with injection pressure, and ambient temperature has more effect on a high-pressure spray than on those with conventional pressures. With the high temperature, the penetration of a high injection pressure spray is reduced a bit, while the spray angle increases obviously. When the high-pressure spray impinges on a wall at ordinary temperature, the rebounding droplets can hardly be seen, but at higher wall temperature, a cloud of dense spray will be observed near the wall, and sometimes a vapor layer will be formed between the spray and the wall. Based on experimental results, an empirical formula considering the effects of both the ambient temperature and injection pressure is presented.

scholarly journals Study on the Phase Selection and Debye Temperature of Hyper-Peritectic Al-Ni Alloy under High Pressure

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Xiaohong Wang ◽  
Zhipeng Chen ◽  
Duo Dong ◽  
Dongdong Zhu ◽  
Hongwei Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Competitive Growth ◽  
Phase Selection ◽  
Debye Temperatures ◽  
Ni Alloy ◽  
Temperature Heat ◽  
Low Temperature Heat Capacity ◽  
New Phase ◽  
Selection Of

The phase selection of hyper-peritectic Al-47wt.%Ni alloy solidified under different pressures was investigated. The results show that Al3Ni2 and Al3Ni phases coexist at ambient pressure, while another new phase α-Al exists simultaneously when solidified at high pressure. Based on the competitive growth theory of dendrite, a kinetic stabilization of metastable peritectic phases with respect to stable ones is predicted for different solidification pressures. It demonstrates that Al3Ni2 phase nucleates and grows directly from the undercooled liquid. Meanwhile, the Debye temperatures of Al-47wt.%Ni alloy that fabricated at different pressures were also calculated using the low temperature heat capacity curve.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

Fuel Droplet Evaporation in a Supercritical Environment

2002 ◽  
Vol 124 (4) ◽  
pp. 762-770 ◽  
Author(s):  
G. S. Zhu ◽  
S. K. Aggarwal
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Ambient Pressure ◽  
Droplet Surface ◽  
Fuel Vapor ◽  
Phase Solubility ◽  
Liquid Density ◽  
Ambient Temperatures ◽  
Droplet Vaporization ◽  
Wide Range

This paper reports a numerical investigation of the transcritical droplet vaporization phenomena. The simulation is based on the time-dependent conservation equations for liquid and gas phases, pressure-dependent variable thermophysical properties, and a detailed treatment of liquid-vapor phase equilibrium at the droplet surface. The numerical solution of the two-phase equations employs an arbitrary Eulerian-Lagrangian, explicit-implicit method with a dynamically adaptive mesh. Three different equations of state (EOS), namely the Redlich-Kwong (RK), the Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK) EOS, are employed to represent phase equilibrium at the droplet surface. In addition, two different methods are used to determine the liquid density. Results indicate that the predictions of RK-EOS are significantly different from those obtained by using the RK-EOS and SRK-EOS. For the phase-equilibrium of n-heptane-nitrogen system, the RK-EOS predicts higher liquid-phase solubility of nitrogen, higher fuel vapor concentration, lower critical-mixing-state temperature, and lower enthalpy of vaporization. As a consequence, it significantly overpredicts droplet vaporization rates, and underpredicts droplet lifetimes compared to those predicted by PR and SRK-EOS. In contrast, predictions using the PR-EOS and SRK-EOS show excellent agreement with each other and with experimental data over a wide range of conditions. A detailed investigation of the transcritical droplet vaporization phenomena indicates that at low to moderate ambient temperatures, the droplet lifetime first increases and then decreases as the ambient pressure is increased. At high ambient temperatures, however, the droplet lifetime decreases monotonically with pressure. This behavior is in accord with the reported experimental data.

Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane–ethane hydrate

2003 ◽  
Vol 81 (1-2) ◽  
pp. 47-53 ◽  
Author(s):  
M B Helgerud ◽  
W F Waite ◽  
S H Kirby ◽  
A Nur
Keyword(s):  
High Pressure ◽  
Shear Wave ◽  
Pressure Dependence ◽  
Gas Hydrate ◽  
Pressure Vessel ◽  
Wave Speed ◽  
Measured Temperature ◽  
Shear Wave Speed ◽  
Temperature And Pressure ◽  
Fixed End

We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane–ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17°C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between –20 and 15°C and 0 to 105 MPa applied piston pressure. PACS No.: 61.60Lj

Pretreatment of Fir Powder and Its Dissolution in Ionic Liquid of 1-(2-Hydroxylethyl)-3-Ethylene Imidazolium Chloride

2011 ◽  
Vol 236-238 ◽  
pp. 87-90
Author(s):  
Li Ying Guo
Keyword(s):  
High Pressure ◽  
Ionic Liquid ◽  
Dissolution Rate ◽  
Mass Fraction ◽  
Wood Powder ◽  
Imidazolium Chloride ◽  
Chemical Structures ◽  
Good Solubility ◽  
Temperature And Pressure ◽  
Pressure Dissolution

Ionic liquid, 1-(2-hydroxylethyl)-3-ethylene imidazolium chloride ([HeVIM]Cl) was synthesized and its chemical structures was examined by FTIR and 1HNMR. Fir powder was extracted with a mixture of benzene/ethanol or activated with 25% (mass fraction) NaOH under normal temperature and pressure, microwave and high pressure. Dissolution of the pretreated wood powder in [HeVIM]Cl by microwave (90°C, 400w) was studied. The results showed that the ionic liquid [HeVIM]Cl exhibited a good solubility. Wood powder pretreated with 25% NaOH under high pressure had the lowest crystallinity (2.4%) and the highest dissolution rate (21.6%).

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