Classification for raw oil inlet conditions of hydrocracking process based on ratio cluster

This study concerned the quality of mini-tablets’ coating uniformity obtained by either the bottom spray chamber with a classical Wurster distributor (CW) or a swirl distributor (SW). Mini-tablets with a diameter of 2.0, 2.5, and 3.0 mm were coated with hypromellose using two different inlet air distributors as well as inlet airflow rates (130 and 156 m3/h). Tartrazine was used as a colorant in the coating layer and the coating uniformity was assessed by spectrophotometric analysis of solutions obtained after disintegration of the mini-tablets (n = 100). Higher uniformity of coating material distribution among the mini-tablets was observed in the case of SW distributor, even for the biggest mini-tablets (d = 3.0 mm), with an RSD no larger than 5.0%. Additionally, coating thickness was evaluated by colorimetric analysis (n = 1000), using a scanner method, and expressed as a hue value. A high correlation (R = 0.993) between inter-tablet variability of hue and UV-Vis results was obtained. Mini-tablets were successfully coated in a fluid bed system using both a classical Wurster distributor as well as a swirl generator. However, regardless of the mini-tablets’ diameter, better film uniformity was achieved in the case of a distributor with a swirl generator.

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Sensitivity analysis of FDA´s benchmark nozzle regarding in vitro imperfections - Do we need asymmetric CFD benchmarks?

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2020-3020 ◽

2020 ◽

Vol 6 (3) ◽

pp. 78-81

Author(s):

Michael Stiehm ◽

Christoph Brandt-Wunderlich ◽

Stefan Siewert ◽

Klaus-Peter Schmitz ◽

Niels Grabow ◽

...

Keyword(s):

Reynolds Number ◽

Flow Field ◽

In Silico ◽

Nozzle Geometry ◽

Geometrical Imperfection ◽

Custom Made ◽

Inlet Conditions ◽

Silicone Model ◽

Bench Testing

AbstractModern technologies and methods such as computer simulation, so-called in silico methods, foster the development of medical devices. For accelerating the uptake of computer simulations and to increase credibility and reliability the U.S. Food and Drug Administration organized an inter-laboratory round robin study of a generic nozzle geometry. In preparation of own bench testing experiment using Particle Image Velocimetry, a custom made silicone nozzle was manufactured. By using in silico computational fluid dynamics method the influence of in vitro imperfections, such as inflow variations and geometrical deviations, on the flow field were evaluated. Based on literature the throat Reynolds number was varied Rethroat = 500 ± 50. It could be shown that the flow field errors resulted from variations of inlet conditions can be largely eliminated by normalizing if the Reynolds number is known. Furthermore, a symmetric imperfection of the silicone model within manufacturing tolerance does not affect the flow as much as an asymmetric failure such as an unintended curvature of the nozzle. In brief, we can conclude that geometrical imperfection of the reference experiment should be considered accordingly to in silico modelling. The question arises, if an asymmetric benchmark for biofluid analysis needs to be established. An eccentric nozzle benchmark could be a suitable case and will be further investigated.

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Effect of Inlet Conditions on the Pressure Drop in Confined Vortex Flow

Journal of Propulsion and Power ◽

10.2514/1.15030 ◽

2005 ◽

Vol 21 (6) ◽

pp. 1128-1133 ◽

Cited By ~ 2

Author(s):

Ali M. Jawarneh ◽

Georgios H. Vatistas

Keyword(s):

Pressure Drop ◽

Vortex Flow ◽

Inlet Conditions

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Simulation of HCCI Combustion Characteristics for Low RON Gasoline Surrogate Fuels

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.694.54 ◽

2014 ◽

Vol 694 ◽

pp. 54-58

Author(s):

Ling Zhe Zhang ◽

Ya Kun Sun ◽

Su Li ◽

Qing Ping Zheng

Keyword(s):

Equivalence Ratio ◽

Chemical Kinetic ◽

Combustion Characteristics ◽

Material Strength ◽

Inlet Temperature ◽

Compression Ignition Engine ◽

Chemical Kinetic Model ◽

Hcci Engine ◽

Surrogate Fuels ◽

Inlet Conditions

A reduced chemical kinetic model (103species and 468 reactions) for new low-RON(research octane number) gasoline surrogate fuels has been proposed. Simulations explored for ignition delay time have been compared with experimental data in shock tubes at pressure of 10atm-55 atm and temperatue of 600-1400 K (fuel/air equivalence ratio=0.5,1.0,2.0 and EGR rate=0, 20%). The simulation data presented 15% enlargement compared with experiments showed applicability of the new kinetic mode in this work. A combustion simulation model has been build for HCCI(homogeneous charge compression ignition) engine with Chemkin-pro. The effects of different air inlet temperature, inlet pressure, engine speed and the fuel air equivalence ratio on the combustion characteristics of the fuel were researched. The results indicated the combustion in an HCCI engine worked sufficiently with lean mixtures and low speed. Meanwhile the material strength could be influenced when the inlet conditions changed. This helps to promote the low-RON gasoline surrogate fuel application in the HCCI engine.

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Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

Volume 7: Turbomachinery, Parts A and B ◽

10.1115/gt2009-59086 ◽

2009 ◽

Author(s):

Farrokh Zarifi-Rad ◽

Hamid Vajihollahi ◽

James O’Brien

Keyword(s):

Experimental Data ◽

Gas Turbine ◽

Turbine Blades ◽

Axial Flow ◽

Experimental Results ◽

Scale Model ◽

Data Set ◽

Pressure Profiles ◽

Scale Models ◽

Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

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Modeling of Compressor Drum Cavities With Radial Inflow

Volume 5A: Heat Transfer ◽

10.1115/gt2016-56505 ◽

2016 ◽

Author(s):

D. Amirante ◽

Z. Sun ◽

J. W. Chew ◽

N. J. Hills ◽

N. R. Atkins

Keyword(s):

Thermal Stratification ◽

Turbulence Modeling ◽

Navier Stokes ◽

Inflow Rate ◽

Cfd Models ◽

Flow And Heat Transfer ◽

Rotating Discs ◽

Computational Fluid Dynamics Cfd ◽

Inlet Conditions ◽

Cooling Air

Reynolds-Averaged Navier-Stokes (RANS) computations have been conducted to investigate the flow and heat transfer between two co-rotating discs with an axial throughflow of cooling air and a radial bleed introduced from the shroud. The computational fluid dynamics (CFD) models have been coupled with a thermal model of the test rig, and the predicted metal temperature compared with the thermocouple data. CFD solutions are shown to vary from a buoyancy driven regime to a forced convection regime, depending on the radial inflow rate prescribed at the shroud. At a high radial inflow rate, the computations show an excellent agreement with the measured temperatures through a transient rig condition. At a low radial inflow rate, the cavity flow is destabilized by the thermal stratification. Good qualitative agreement with the measurements is shown, although a significant over-prediction of disc temperatures is observed. This is associated with under prediction of the penetration of the axial throughflow into the cavity. The mismatch could be the result of strong sensitivity to the prescribed inlet conditions, in addition to possible shortcomings in the turbulence modeling.

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One-dimensional adiabatic flow of equilibrium gas–particle mixtures in long vertical ducts with friction

Journal of Fluid Mechanics ◽

10.1017/s002211208900145x ◽

1989 ◽

Vol 203 ◽

pp. 251-272 ◽

Cited By ~ 33

Author(s):

Guido Buresti ◽

Claudio Casarosa

Keyword(s):

Equilibrium Mixture ◽

Adiabatic Heating ◽

Explosive Eruptions ◽

Perfect Gas ◽

Typical Application ◽

One Dimensional ◽

Adiabatic Flow ◽

Flow Parameters ◽

Constant Area ◽

Inlet Conditions

The equations of the steady, adiabatic, one-dimensional flow of an equilibrium mixture of a perfect gas and incompressible particles, in constant-area ducts with friction, are derived taking into account the effects of gravity and of the finite volume of the particles. As is the case for a pure gas, the mixture is shown to be subject to the phenomenon of choking, and the possibility of an adiabatic heating of the mixture in a subsonic expansion is also theoretically predicted for certain flow inlet conditions. The model may be used to approximately describe the conditions existing in portions of volcanic conduits during the Plinian phases of explosive eruptions. Some results of the numerical integration of the equations for a typical application of this type are briefly discussed, thus showing the potential of the model for carrying out rapid analyses of the influence of the main geometrical and flow parameters describing the problem. A non-volcanological application is also analysed to illustrate the possibility of the adiabatic heating of the mixture.

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