scholarly journals Fluiddynamik in der Cigarette und deren Einfluß auf den Zugwiderstand

1994 ◽  
Vol 16 (1) ◽  
pp. 11-46 ◽  
Author(s):  
H Gaißer
Keyword(s):  
Fluid Dynamics ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Flow Characteristics ◽  
Linear Partial Differential Equation ◽  
Fluid Volume ◽  
Model Parameters ◽  
Storage Element ◽  
Pressure Drops ◽  
Fluid Network

AbstractThe objective of the theoretical study is to present a model that simulates the instationary flow characteristics within cigarettes which are adjusted to a routine smoking machine. By assuming laminar fluid flow the well knownKozeny-Carman equation is used to evaluate the flow impedance of cigarettes. The model parameters are determined by five variations of routine pressure-drop measurements yielding the entire set of flow impedances, which are necessary for describing a steady state Fluid-Network. Using this relation further elements of the fluid dynamics, e.g. the Fluid-Inductor, a storage element of kinetic energy (fluid inertor), and the Fluid-Capacitor, a storage element of potential energy (fluid volume), are evaluated. In addition, the electrical and fluid dynamical analogies are demonstrated. The model uses a set of distributed parameters including pneumatic impedances, capacitors and inductors, to represent filtered cigarettes and a second order linear partial differential equation to describe the fluid flow within the cigarettes. A simple presentation of the Fluid-Network with lumped parameters is analysed and its significant time constants are determined. A characteristical value for the time constant of the cigarette fluid-inertor is given by TL ≈ 0.02 ms and depending on the fluid volume of cigarette their dominant time parameter is given by TC ≈ 2 ms. Finally the transient fluid flow within cigarettes in a conventional smoking machine is considered including a simulation of their fluid dynamics. A simple estimation gives the time response of the system (consisting of cigarettes and routine smoking machine) with TcR ≈ 70 ms as a product of dead and sweep volume times the pressure drop of unencapsulated cigarettes. Variation of parameters caused by cigarette pressure drops and dead volumes of the smoking machine are simulated and discussed.

Using Computational Fluid Dynamics (CFD) for Evaluation of Fluid Flow Through a Gate Valve

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Gate Valve ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Type Equation ◽  
Pharmaceutical Products ◽  
Computational Fluid Dynamics Cfd

Abstract Gate valves are the most common valve in industrial plants. However, there is no work in the literature regarding the use of computational fluid dynamics (CFD) to evaluate the fluid flow characteristics and pressure drop in gate valves. The present work evaluated the fluid flow and pressure drop through a commercial gate valve using CFD. The obtained values for the pressure loss coefficient (k) are in accordance to those described in the literature and a power type equation could be used for modeling it as function of the Reynolds Number. Fluid flow behavior through the gate valve highlighted the flow recirculation and stagnant areas, being critical for food and pharmaceutical products processing. The obtained results reinforce the advantages in using CFD as a tool for the engineering evaluation of fluid processes.

Numerical Investigation of Dusts Removal from Tramway Surface by Street Vacuum Sweeper

2011 ◽  
Vol 236-238 ◽  
pp. 1619-1622 ◽  
Author(s):  
Bo Fu Wu ◽  
Jin Lai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Pressure Drop ◽  
Removal Efficiency ◽  
Pressure Drops ◽  
Operational Safety ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

In order to enhance the operational safety of tram vehicle and reduce the wear of guide wheels mounted on the vehicle, it is necessary to remove particles such as dusts and silts from tramway surface. The aim of this paper is to evaluate the effectiveness of street vacuum sweeper for sucking up dusts from tramway surface. A numerical model was developed based on dusts removal process. Under different pressure drops across the pickup head of the street vacuum sweeper, the flow field and dusts removal efficiency were analyzed with computational fluid dynamics (CFD) method. The numerical results show that a higher pressure drop can improve the airflow field in the pickup head and results in higher dusts removal efficiency, but higher pressure drop definitely need more energy. Therefore, a balance should be taken into consideration.

scholarly journals Predicting the Pressure Drops across Cellulose Acetate Filters

1986 ◽  
Vol 13 (4) ◽  
pp. 157-168
Author(s):  
RW Dwyer
Keyword(s):  
Fluid Flow ◽  
Theoretical Model ◽  
Pressure Drop ◽  
Cellulose Acetate ◽  
Flow Rate ◽  
Fluid Flow Rate ◽  
Cross Sectional ◽  
Cigarette Filter ◽  
Pressure Drops

AbstractA theoretical model of the pressure drop across a fibrous cigarette filter is derived. The pressure drop is expressed as a function of the filter dimensions, the fiber tow characteristics, the filter weight, the fluid flow rate, and a filter fiber factor. The fiber factor is affected by the distribution of the fibers within the filter, the relative orientations of the fibers, and their cross-sectional shapes. The model allows one to accurately calculate the influences of these variables on the filter pressure drop. Additionally, it can be used to predict capability curves and select an optimum cellulose acetate tow for a given filter pressure drop.

scholarly journals ANALISA PRESSURE DROP DENGAN PENAMBAHAN ZAT ADITIF CAIRAN COOLANT PADA PIPA SILINDER MENGGUNAKAN METODE EMPIRIS DAN METODE EKSPERIMEN

2018 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Irwan Setiawan ◽  
Nurrohman . ◽  
Hablinur Al Kindi
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Fluid Velocity ◽  
Flow Characteristics ◽  
Data Retrieval ◽  
Piping System ◽  
Problem Analysis ◽  
Calibration Data ◽  
Literature Study ◽  
Pipe Length

The flow of fluid through the pipe creates fluid friction with pipe walls causing pressure drop and fluid flow velocity affecting the use of energy to drain it. Pressure drop can be affected by several factors such as friction or friction factor, pipe length, pipe diameter and fluid velocity. In this research, it will analyze pressure drop on piping system based on friction, fluid flow characteristics, and fluid velocity. The analysis was done by using two methods, namely experimental method and empirical calculation method. The stages of this study consist of problem analysis, literature study, calibration, data retrieval, empirical data processing and experiments, validation, analysis of results and conclusions. Based on the results of empirical and experimental research, the lowest pressure drop in the experiment and empirical was the 12 LPM discharge copper pipe and the water coolant ratio is 0: 100. This means that the best material pipes used were copper pipes rather than steel and galvanized pipes. The results of the tests and experiments have been tested for validation. The validation value of empirical and experimental data measurement is 91%.

scholarly journals The effect to flow rate characteristic on biodegradation of bone scaffold

2017 ◽  
Vol 13 (4-2) ◽  
pp. 546-552 ◽  
Author(s):  
Hasan Basri ◽  
Jimmy Deswidawansyah Nasution ◽  
Ardiyansyah Syahrom ◽  
Mohd Ayub Sulong ◽  
Amir Putra Md. Saad ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Computational Models ◽  
Shear Stresses ◽  
Experimental Conditions ◽  
Flow Rates ◽  
Pressure Drops ◽  
Bone Scaffolds ◽  
Wall Shear

This paper proposes an improved modeling approach for bone scaffolds biodegradation. In this study, the numerical analysis procedure and computer-based simulation were performed for the bone scaffolds with varying porosities in determining the wall shear stresses and the permeabilities along with their influences on the scaffolds biodegradation process while the bio-fluids flow through within followed with the change in the flow rates. Based on the experimental study by immersion testing from 0 to 72 hours of the time period, the specimens with different morphologies of the commercial bone scaffolds were collected into three groups samples of 30%, 41%, and 55% porosities. As the representative of the cancellous bone morphology, the morphological degradation was observed by using 3-D CAD scaffold models based on microcomputed tomography images. By applying the boundary conditions to the computational fluid dynamics (CFD) and the fluid-structure interaction (FSI) models, the wall shear stresses within the scaffolds due to fluid flow rates variation had been simulated and determined before and after degradation. The increase of fluid flow rates tends to raise the pressure drop for scaffold models with porosities lower than 50% before degradation. As the porosities increases, the pressure drop decreases with an increase in permeability within the scaffold. The flow rates have significant effects on scaffolds with higher pressure drops by introducing the wall shear stresses with the highest values and lower permeability. These findings indicate the importance of using accurate computational models to estimate shear stress and determine experimental conditions in perfusion bioreactors for tissue engineering more accurate results will be achieved to indicate the natural distributions of fluid flow velocity, wall shear stress, and pressure.

An Effect of Fractal Flow Conditioner Thickness on Turbulent Swirling Flow

2013 ◽  
Vol 315 ◽  
pp. 93-97 ◽  
Author(s):  
Bukhari Manshoor ◽  
N.F. Rosidee ◽  
Amir Khalid
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Pressure Drop ◽  
Swirling Flow ◽  
Plate Thickness ◽  
Flow Characteristics ◽  
Space Filling ◽  
Flow Through ◽  
Experimental Fluid ◽  
Good Agreement

Fractal flow conditioner is a flow conditioner with a fractal pattern and used to eliminate turbulence originating from pipe fittings in experimental fluid flow applications. In this paper, steady state, incompressible, swirling turbulent flow through circle grid space filling fractal plate (Fractal flow conditioner) has been studied. The solution and the analysis were carried out using finite volume CFD solver FLUENT 6.2. The turbulence model used in this investigation is the standardk-εmodel and the results were compared with the pressure drop correlation of BS EN ISO 5167-2:2003. The results showed that the standardk-εmodel gave a good agreement with the ISO pressure drop correlation. Therefore, the model was used further to predict the effects of circle grids space filling plate thickness on the flow characteristics.

Laminar Fluid Flow in a Planar 90 Degree Bifurcation With and Without a Protruding Branching Duct

1996 ◽  
Vol 118 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. G. Travers ◽  
W. M. Worek
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Velocity Field ◽  
Pressure Drop ◽  
Laminar Flow ◽  
Flow Field ◽  
Numerical Study ◽  
Main Duct

The laminar flow field in a planar, ninety degree bifurcation is examined. This numerical study uses the computational-fluid-dynamics software Fluent Version 4.11. First, the velocity field in a bifurcation without a protruding branching duct is modeled, and the results are successfully compared to experimental data. Next, the flow field is studied in bifurcations that have branching ducts that protrude into the main duct. The velocity field and pressure drop are documented, and are found to be strongly influenced by the extent of the branching duct protrusion.

Numerical Investigation of Heat Transfer and Fluid Flow Characteristics in Circular Wavy Microchannels with Sidewall Rib

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Ranjith Kumar Valaparla ◽  
Karthik Balasubramanian ◽  
Kupireddy Kiran Kumar
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Numerical Investigation ◽  
Heat Sink ◽  
Flow Characteristics ◽  
Computational Domain ◽  
Hexahedral Elements ◽  
Fluid Flow Characteristics

AbstractPurpose: Numerical investigation was carried out to study the hydro-thermal characteristics in circular wavy microchannels (CWMCs) with sidewall rib. Thermal resistance and pressure drop penalty were compared with sinusoidal wavy microchannels (SWMCs) design. Parametric study on sidewall rib was also carried to minimize the pressure drop penalty and to achieve lower thermal resistance. Introducing sidewall rib in the CWMCs leads to the formation of more Deans vortices. This leads to an effective fluid mixing and augments the convective heat transfer. Design methodology/approach: A computational solid domain was created in SOLIDWORKS and the fluid domain was produced by circular arc profile for the entire length of heat sink. 3-D numerical investigation was carried out using ANSYS FLUENT software. Created computational domain was imported into ANSYS WORKBENCH. Meshing was executed in ANSYS mesh module. The computational domains were meshed using hexahedral elements adopting match control on both sides of microchannel (MC). The numerical investigation was carried out in the Re range from 100 to 300 with constant heat flux (50 W/cm2) applied at the bottom of the channel. Heat transfer and fluid flow characteristics were explained with velocity vectors, velocity contours and temperature contours. Findings: From numerical studies, it is concluded that CWMC with sidewall rib width (0.15 mm) leads to 33.6 % lower thermal resistance than SWMC with pressure drop penalty. Originality/Value: Present study is useful to identify the optimum deign to augment the heat dissipation performance of microchannel heat sink.

Computational Fluid Dynamics-Based Numerical Analysis of Acoustic Attenuation and Flow Resistance Characteristics of Perforated Tube Silencers

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Chen Liu ◽  
Zhenlin Ji
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Time Domain ◽  
Transmission Loss ◽  
Air Flow ◽  
Acoustic Attenuation ◽  
Pressure Drops ◽  
Wave Range ◽  
Perforated Tube

The 3D time-domain computational fluid dynamics (CFD) approach is used to calculate the acoustic attenuation performance of perforated tube silencers without and with flow. For the crossflow perforated tube silencer and straight-through perforated tube silencers, the transmission loss predictions agree well with the experimental measurements available in the literature. Then, the 3D time-domain CFD approach is employed to investigate the effects of flow velocity and temperature on the acoustic attenuation performance of perforated tube silencers. The numerical results demonstrated that the transmission loss is increased at most frequencies for the crossflow perforated tube silencer as the air flow increases, while the air flow has little influence on the acoustic attenuation in the plane wave range and increases the acoustic attenuation at higher frequencies for the straight-through perforated tube silencers. Increasing the air temperature shifts the transmission loss curve to higher frequency and lowers the resonance peaks somewhat. The pressure drops of perforated tube silencers are predicted by performing the 3D steady flow computation using CFD. The pressure drop of the crossflow perforated tube silencer is much higher than those of the straight-through perforated tube silencer at the same flow conditions, and the pressure drop of the straight-through perforated tube silencer increases gradually as the porosity increases.

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