Optimized Pressure Determined in Accordance with Variable Plunger Stroke of Internal Injector NGV

2017 ◽  
Vol 370 ◽  
pp. 41-51 ◽  
Author(s):  
Kwon Se Kim ◽  
Doo Seuk Choi
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Analytical Model

Using an analytical model, a clear investigation was performed into the phenomenon of decreasing overall pressure and velocity of a plunger when its stroke within a natural gas injector changes. The results indicated the following mesh sizes from the mesh matrix: 0.0005 mm minimum, 12.7 mm maximum, 1,107,420 nodes, and 5,856,567 elements. Consequently, the pressure was affected by the stroke height from the designed plunger shape, and although the height of the plunger stroke changes over 0.150 mm, the absence of the phenomenon of pressure drop was noticeable.

Performance comparison of electrorheological valves with two different geometric configurations: Cylinder and plate

2008 ◽  
Vol 223 (3) ◽  
pp. 573-581 ◽  
Author(s):  
Y-M Han ◽  
K-G Sung ◽  
J W Sohn ◽  
S-B Choi
Keyword(s):  
Pressure Drop ◽  
Response Time ◽  
Analytical Model ◽  
Performance Comparison ◽  
Time Varying ◽  
Control Performance ◽  
Electrode Gap ◽  
Design Constraint ◽  
Geometric Configurations ◽  
Er Fluid

This article presents a control performance comparison of electrorheological (ER) fluid-based valves between cylindrical and plate configurations. After identifying Bingham characteristics of chemical starch-based ER fluid, an analytical model of each valve is established. In order to reasonably compare valve performance, design constraint is imposed by the choosing the same electrode gap and length, and each ER valve is manufactured. Valve performances such as pressure drop and response time are then evaluated and compared through analytical model and experiment. In addition, a time-varying pressure tracking controllability of each ER valve is experimentally realized.

Analysis of MHD Pressure Drop in Packed Pebble Bed-Based Blanket for FDS

2013 ◽  
Author(s):  
Hongyan Wang ◽  
Chan Tang
Keyword(s):  
Pressure Drop ◽  
Liquid Metal ◽  
Analytical Model ◽  
Interaction Parameter ◽  
Metal Flow ◽  
Hybrid Reactor ◽  
Pebble Bed ◽  
Critical System ◽  
Liquid Metal Flow ◽  
Flow Through

The Fusion-Driven Sub-critical System as a multifunctional hybrid reactor has been investigated in ASIPP. The liquid metal LiPb flow through a packed pebble bed-based blanket is considered to be one of the blanket candidates. In this contribution, the Magnetohydrodynamics (MHD) pressure drop of liquid metal flow through the packed pebble bed has been calculated and analyzed under various conditions including (a) the size of the packed pebbles; (b) the ratio of occupied room by the packed pebbles to that of liquid metal; and (c) whether the pebbles surface is insulated or not. Furthermore, asymptotic techniques to analyze large Hartmann parameter flow and interaction parameter flow are employed and an analytical model has been developed for the calculations of MHD pressure drop of liquid metal flow in a packed pebble bed. The appropriate method for calculating the MHD effects on the pressure drop through the packed pebble bed-based blanket for the FDS has been presented.

Comparative Study of Effective Cooling in Microchannel Heat Sinks (MCHS) With Nanofluid and Hydrophobic Nanostructures Using Computational Fluid Dynamics

2020 ◽  
Author(s):  
Darryl Jennings ◽  
Sonya Smith
Keyword(s):  
Pressure Drop ◽  
Analytical Model ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Heat Sinks ◽  
Cross Sectional ◽  
Ansys Fluent ◽  
Cooling Flow ◽  
Micro Channels ◽  
The Impact

Abstract The goal of this research is to present an analytical model of nanostructures and study the effects of their geometry on the performance of micro channels. The pressure drop experienced by micro channels is of interest as it presents a limit on forced convection heat transfer. This work will demonstrate how the presence of nanostructures primarily affects pressure drop as well as other cooling flow characteristics. Additional work in the impact of microchannel cross-sectional geometry and friction factor formulation is provided as well. Multiple transient analyses were performed in ANSYS FLUENT to ascertain performance characteristics of microchannels without the presence of hydrophobic nanostructures. The results were compared to the analytical model developed in this study.

scholarly journals Review and analysis of historical leakages from storage salt caverns wells

2019 ◽  
Vol 74 ◽  
pp. 27 ◽  
Author(s):  
Pierre Bérest ◽  
Arnaud Réveillère ◽  
David Evans ◽  
Markus Stöwer
Keyword(s):  
Rock Mass ◽  
Pressure Drop ◽  
Natural Gas ◽  
Ground Surface ◽  
Ground Level ◽  
Salt Dome ◽  
Wellhead Pressure ◽  
Well Design ◽  
Salt Caverns ◽  
Geological Formations

Twelve incidents involving well casing and/or cement leaks in the salt caverns storage industry are described. These incidents occurred at the following storage sites: Eminence salt dome, Mississippi; Elk City, Oklahoma; Conway, Kansas; Yoder, Kansas; Mont Belvieu, Texas; Teutschenthal/Bad Lauchstädt, Germany; Clute, Texas; Mineola, Texas; Hutchinson, Kansas; Magnolia, Louisiana; Boling, Texas; Epe, Germany. Mechanisms leading to a casing leak and consequences are discussed. In most cases, a breach in a steel casing occurred at a depth where a single casing was isolating the stored product from the geological formations. The origin of the breach was due in most cases to poor welding/screwing conditions and corrosion, or excessive deformation of the rock formation. In this, the age of the well is often influential. In many cases, the leak path does not open directly at ground level; fugitive hydrocarbons first escape and accumulate in the subsurface prior to migrating through shallower horizons and escaping at ground surface. A pressure differential between hydrocarbons in the borehole and fluids in the rock mass favours fast leak rates. A wellhead pressure drop often is observed, even when the stored product is natural gas. The incidents described suggest that thorough monitoring (tightness tests) and a correct well design would lessen considerably the probability of a casing leak occurring.

Design Improvement Survey for NOx Emissions Reduction of a Heavy-Duty Gas Turbine Partially Premixed Fuel Nozzle Operating With Natural Gas: Experimental Campaign

2015 ◽  
Author(s):  
Matteo Cerutti ◽  
Roberto Modi ◽  
Danielle Kalitan ◽  
Kapil K. Singh
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Gas Turbine ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Fuel Nozzle ◽  
Partially Premixed ◽  
Heavy Duty Gas Turbine ◽  
The Impact

As government regulations become increasingly strict with regards to combustion pollutant emissions, new gas turbine combustor designs must produce lower NOx while also maintaining acceptable combustor operability. The design and implementation of an efficient fuel/air premixer is paramount to achieving low emissions. Options for improving the design of a natural gas fired heavy-duty gas turbine partially premixed fuel nozzle have been considered in the current study. In particular, the study focused on fuel injection and pilot/main interaction at high pressure and high inlet temperature. NOx emissions results have been reported and analyzed for a baseline nozzle first. Available experience is shared in this paper in the form of a NOx correlative model, giving evidence of the consistency of current results with past campaigns. Subsequently, new fuel nozzle premixer designs have been investigated and compared, mainly in terms of NOx emissions performance. The operating range of investigation has been preliminarily checked by means of a flame stability assessment. Adequate margin to lean blow out and thermo-acoustic instabilities onset has been found while also maintaining acceptable CO emissions. NOx emission data were collected over a variety of fuel/air ratios and pilot/main splits for all the fuel nozzle configurations. Results clearly indicated the most effective design option in reducing NOx. In addition, the impact of each design modification has been quantified and the baseline correlative NOx emissions model calibrated to describe the new fuel nozzles behavior. Effect of inlet air pressure has been evaluated and included in the models, allowing the extensive use of less costly reduced pressure test campaigns hereafter. Although the observed effect of combustor pressure drop on NOx is not dominant for this particular fuel nozzle, sensitivity has been performed to consolidate gathered experience and to make the model able to evaluate even small design changes affecting pressure drop.

scholarly journals Parameters in Multiphase Flowing of Natural Gas NGH Slurry via Vertical Pipe

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Dai Maolin ◽  
Wu Kaisong
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Solid Particles ◽  
Small Scale ◽  
Vertical Pipe ◽  
Particle Volume ◽  
The Relationship

In recent years, the pipeline flowing of natural gas hydrate (hereinafter NGH) slurry has been a promising technique of multiphase flowing via pipe and that of crushed hydrate mixture slurry is also a key technique in solid fluidization mining method of nondiagenetic NGH reservoir below the seabed. In this paper, by using similarity rules, a small-scale simulation model was established to shorten the calculation time. The correctness of the simulation model has been verified through comparison with experiment. Thereby, the distribution of velocity and volume fraction of each phase in the vertical pipe was obtained, and the prototype of vertical pipe was analyzed. By study on the pipe resistance, the pressure drop of slurry, when flowing in vertical pipe, could be calculated asΔP=ρgh+0.23Cρv1.8. In the end, by adjusting volume fraction of particles in the mixture slurry, the relationship between the solid particles’ volume fraction and piezometric pressure drop was obtained. When the optimal flow velocity of the slurry is 2 m/s and the ratio of NGH volume fraction to that of sand is 4 : 1, the optimal particle volume fraction ranges from 20% to 40%.

CFD Analysis of the Effect of Rolling Motion on the Characteristic of Labyrinth Seal

2017 ◽  
Author(s):  
Ning Huang ◽  
Zhenlin Li ◽  
Shiyao Li ◽  
Ning Zhang ◽  
Zhihui Dong
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Performance Characteristic ◽  
Oil And Gas ◽  
Internal Flow ◽  
Oil And Gas Industry ◽  
Labyrinth Seal ◽  
Rolling Motion ◽  
Turbo Expander ◽  
Liquid Natural Gas

With the development of offshore oil and gas industry, LNG turbo expanders are widely used in Floating Liquid Natural Gas equipment (FLNG) for natural gas transportation. The performance characteristic of the turbo expander is significant affected by the rolling motion caused by the ocean conditions. As an important part of expander, the labyrinth seal is directly related to the safety of the expander, so it is necessary to study the performance characteristic of labyrinth seal under rolling motion. In this paper, CFD is used to simulate the internal flow field of labyrinth seals under different rolling periods and sloshing amplitudes conditions. The distribution of the pressure drop is obtained, and the influence of rolling motion on different labyrinth seal radial clearances and cavity depths are discussed. The results indicate that variation periods of the pressure drop are consistent with the rolling periods, and the larger the rolling amplitude is, the larger pressure drop fluctuation can be observed. Additionally, the fluctuation characteristic is significantly affected by gap widths and cavity depths.

scholarly journals Modeling of Laminar Flows in Rough-Wall Microchannels

2005 ◽  
Vol 128 (4) ◽  
pp. 734-741 ◽  
Author(s):  
R. Bavière ◽  
G. Gamrat ◽  
M. Favre-Marinet ◽  
S. Le Person
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Numerical Modeling ◽  
Pressure Drop ◽  
Analytical Model ◽  
Analytical Approach ◽  
Laminar Flows ◽  
Numerical Results ◽  
Rough Wall ◽  
Relative Roughness

Numerical modeling and analytical approach were used to compute laminar flows in rough-wall microchannels. Both models considered the same arrangements of rectangular prism rough elements in periodical arrays. The numerical results confirmed that the flow is independent of the Reynolds number in the range 1–200. The analytical model needs only one constant for most geometrical arrangements. It compares well with the numerical results. Moreover, both models are consistent with experimental data. They show that the rough elements drag is mainly responsible for the pressure drop across the channel in the upper part of the relative roughness range.

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