Numerical Investigation Of Pressure Drop Research Articles

Numerical investigation of pressure drop within isothermal capillary rheometry for viscous and viscoelastic fluids

Abstract In capillary rheometry of a polymer melt, the total pressure drop consists of three primary components: shear viscosity, extensional viscosity, and normal stress differences. Traditionally, viscoelastic constitutive equations have been used to produce accurate predictions regarding the pressure drop. It is difficult to investigate the primary components in past experimental measurements and numerical computations. The useful improvement of the classic White-Metzner viscoelastic constitutive equation coupled with the weighted shear/extension viscosity is performed in isothermal capillary flow simulations. It is significant to analyze the extension-induced pressure drop for a short die and the shear-induced pressure drop for a long die, along with a small contribution of normal stress differences.

A proposal for a correlation to calculate pressure drop in reticulated porous media with the help of numerical investigation of pressure drop in ideal & randomized reticulated structures

This paper presents a numerical investigation to estimate pressure drop in fluid flow through reticulated ideal and randomized porous structures. The 3D open-cell foam geometries are constructed using an in-house code along with the use of visualization tool kit (VTK) libraries. In this study, the ideal and randomized Kelvin structures with different porosities and pore densities are generated. These structures have been used to perform direct pore level simulations (DPLS) with the aid of a commercial CFD software. The simulation results are used to acquire the pressure drop across the structures. The pressure drop variation with respect to pore density, porosity, specific surface area, and randomization are analyzed and a pressure drop correlation for reticulated structures with new values of viscous and inertial coefficients is proposed. The validity of the proposed correlation is compared against the experimental and numerical data of the real structures that are available in the literature.

Numerical Investigation of Pressure Drop in Single Pellet String Reactors

AbstractIn narrow fixed‐bed reactors the influence of the confining wall on pressure drop cannot be neglected. Here, the pressure drop in single pellet string reactors, a limiting case of fixed‐bed reactors with a cylinder‐to‐particle diameter ratio below 2, is studied using computational fluid dynamics simulations. Deviations to the Ergun, and more specifically Blake‐Kozeny equation are evident though the general trend is met. A geometry‐based weighting factor is introduced to scale the influence of the confining wall in an equivalent diameter expression. Agreement between numerical simulation and pressure drop predictions from correlation are thereby improved significantly.

Numerical Investigation of Pressure Drop for Various Models of Catalytic Converter to Capture CO2 Emission using Activated Carbon

Internal combustion engines are found to be extensively used in both mobile and stationary applications. The major drawbacks in diesel engines are the release of harmful gases like HC, CO, NOx and PM into atmosphere. There is several pre combustion and post combustion techniques are available to control these emissions effectively. Although CO2 emissions from I.C engines considered as a regulated emission but it is a leading contributor towards Greenhouse gases. In this work a numerical investigation on backpressure was carried out by varying porosity factor of activated carbon. Activated Carbon seems to be viable substance to capture CO2 emission from diesel exhaust. To evaluate the backpressure an analysis was carried out using CFD ANSYS fluent software. In the present investigation an analysis is carried out by placing activated carbon at three different variations. Then the analysis are done by varying three different porosity percentages 30,35 and 45 by placing activated carbon at three different locations. Final study reveals that activated carbon placed at PC35-3 layout shows optimum backpressure and high filtration efficiency while compared with other two layouts.

Numerical investigation of pressure drop and heat transfer in pin fin heat sink and micro channel pin fin heat sink

Numerical investigation of pressure drop and heat transfer in pin fin heat sink and micro channel pin fin heat sink

Numerical investigation of pressure drop and heat transfer through open cell foams with 3D Laguerre-Voronoi model

This work reviews the theoretical backgrounds of pressure drop prediction for open cell foams. The pressure drop of open cell foams was investigated on aluminum foam structures of pore densities 10–50ppi and porosities 70–95%, with the commercial CFD analysis package: ANSYS Fluent, and performed over flow velocities ranging from 0.5m/s to 20m/s. The 3D foam structures were created by Laguerre-Voronoi tessellations. The numerical results for pressure drop were compared with the theoretical predictions by Inayat et al. and experimental data in the literature. The results show that the pressure drop of foams increases with increasing pore density and decreasing porosity. The numerical results are consistent with theoretical predictions and experimental data. The computed interfacial heat transfer coefficient was investigated. The Nusselt number increases with increasing Reynolds number, and increases with increasing porosity at constant pore density. The friction factor of foams was also evaluated.

Experimental and numerical investigation of pressure drop and heat transfer coefficient in converging–diverging microchannel heat sink

The major challenge in microelectronic chips is to eliminate the generated heat for stable and reliable operation of the devices. Microchannel heat sinks are efficient method to dissipate high heat flux. The pressure drop and heat transfer coefficient are the important parameters which determine the thermal–hydraulic performance of the microchannel heat sink. In this study, a converging–diverging (CD) microchannel heat sink was experimentally investigated for the variation of pressure drop and heat transfer coefficient. De-ionized water was considered as the working fluid. Experiments were conducted for single phase fluid flow with mass flow rate and heat flux ranging from 0.001232 to 0.01848 kg/s and 10–50 W/cm2 respectively. The fluid and solid temperature were measured to calculate the heat transfer coefficients. Numerical results were computed using the CFD software and validated against the experimental results. The CD microchannel possesses high heat transfer coefficient than the straight microchannels. Theoretical correlations were proposed for comparing the experimental Nusselt number of CD microchannel. Evaluation of thermal–hydraulic performance of CD microchannel is important to quantify its applications in electronics cooling.

Numerical Investigation of Pressure Drop and Erosion Wear by Computational Fluid Dynamics Simulation

Numerical Investigation of Pressure Drop and Erosion Wear by Computational Fluid Dynamics Simulation

Numerical investigation of pressure drop and heat transfer through reconstructed metal foams and comparison against experiments

Direct numerical simulation of transport in foam materials can benefit from realistic representations of the porous-medium geometry generated by employing non-destructive 3D imaging techniques. X-ray microtomography employs computer-processed X-rays to produce tomographic images or slices of specific regions of the object under investigation, and is ideally suited for imaging opaque and intricate porous media. In this work, we employ micro-CT for numerical analysis of air flow and convection through four different high-porosity copper foams. All four foam samples exhibit approximately the same relative density (6.4–6.6% solid volume fraction), but have different pore densities (5, 10, 20, and 40 pores per inch, PPI). A commercial micro-computed tomography scanner is employed for scanning the 3D microstructure of the foams at a resolution of 20μm, yielding stacks of two-dimensional images. These images are processed in order to reconstruct and mesh the real, random structure of the foams, upon which simulations are conducted of forced convection through the pore spaces of the foam samples. The pressure drop values from this μCT based CFD analysis are compared against prior experimental results; the computational interfacial heat transfer results are compared against the values predicted by an empirical correlation previously reported, revealing excellent agreement between the numerical and experimental/empirical hydraulic and thermal results, thus highlighting the efficacy of this novel approach.

Numerical investigation of pressure drop and heat transfer in developing laminar and turbulent nanofluid flows

This paper concerns the study of laminar and turbulent force convection heat transfer and pressure drop between horizontal parallel plates with a nanofluid composed of Al2O3 and water. A set of governing equations are solved using a non-staggered SIMPLE procedure for the velocity–pressure coupling. For the convection–diffusion terms a power-law scheme is employed. A modified k–ε model with a two-layer technique for the near-wall region has been used to predict the turbulent viscosity. The effects of nanoparticle volume fraction in the base fluid on laminar and turbulent flow variables are presented and discussed. The velocity and temperature profiles, friction factor, pressure coefficient and Nusselt number at different Reynolds numbers in the entrance region for both the laminar and turbulent flow regimes are reported under different thermal boundary conditions. The results show that the effect of the presence of nanoparticles in the base fluid on hydraulic and thermal parameters for the turbulent flow is not very significant, while the rate of heat transfer for the laminar flow with nanoparticles is greater than that of the base liquid. Furthermore, the thermal boundary layer and consequently the Nusselt number more quickly reach their fully developed values by increasing the percentage of nanoparticles in the base fluid for the laminar flow regime, while no changes in the trend are observed for the turbulent flow.