Influence Of Porous Media Research Articles

Influence of porous media on heat transfer of hydrocarbon fuel in the regenerative cooling channel under different heating surfaces

The regenerative cooling technology which uses endothermic hydrocarbon fuel as coolant provides guarantee for the efficient operation of scramjet. The porous medium used in the regenerative cooling channel can enhance heat transfer to increase the heat sink of hydrocarbons due to its high thermal conductivity. To further elucidate the effect of porous media in the actual regenerative cooling, this paper constructs a three-dimensional cooling channel filled with porous media under different heating surfaces in the numerical simulations. The simulation results show that the buoyancy of fuel fluid under different heating surfaces is different, causing different behavior of the fluid flow direction on the cross section. Bottom heating produces the best heat transfer effect in the regenerative cooling channels with/without porous media. When porous medium is added in the cooling channel, its high thermal conductivity is conducive to energy transport, leading to the reduction of the density stratification and temperature non-uniformity coefficient, and the outlet temperature and heat sink of fuel fluid are increased. In addition, the obstructing effect of porous media causes the cross-sectional fluid flow direction to change in the cooling channel, and the most significant obstruction is observed in the case of the top heating process.

Buongiorno’s radiative Prandtl-Eyring nanofluid flow through porous medium over a stretching surface with cross-diffusion effects

The main focus of the current analysis is to describe the thermo-magnetic flow, heat and mass transport features of two-dimensional dissipative Prandtl-Eyring nanofluid (PE-NF) flow over a stretching sheet under the influence of porous medium and magnetic Ohmic dissipation numerically. An innovative Buongiorno’s nanofluid model in terms of Brownian motion and thermophoresis is deployed to accurately simulate the nano behavior in Prandtl-Eyring within the boundary layer regime. The thermal radiation and heat source/sink effects are also included to describe the thermal transport process. In addition to this, the thermo-diffusion and diffusion-thermo effect are included to demonstrate the temperature and concentration diffusion mechanism under the presence of chemical reaction process. The emerged coupled nonlinear two-dimensional time-independent partial differential equations are rendered to their dimensionless form through appropriate similarity transformations and solved by deploying Matlab-based BVP4C technique. The graphical visualization showed that, the increasing magnetic number diminished the flow field and enhanced the temperature and concentration profiles in the flow regime. Rising porous parameter decayed the Prandtl-Eyring nanofluid velocity. Increasing radiation and Eckert numbers enhance the temperature field in the flow regime. Magnifying Prandtl-Eyring parameter suppressed the velocity diffusion. Increasing Brownian motion and thermophoresis parameters increases the temperature profile. Amplifying Soret parameter upsurges the concentration profile. Skin-friction coefficient amplified with enhanced magnetic and porous numbers. Heat transfer rate acts as increasing function of thermophoresis and Brownian motion parameters. The main objective of this study is the addition of magnetic Ohmic dissipation, radiation, porous medium, thermal source/sink, Soret and Dufour effects and Buongiorno nanofluid model and this consideration generalizes former studies and gives a new re-defined mathematical formulation of heat and mass transport features of Prandtl-Eyring nanofluid flow over a stretching sheet. Finally, the numerical accuracy of the current similarity results is validated with available solutions and noticed a good agreement.

Influence of porous media and substrate rotation on AlN growth in MNVPE reactors based on CFD simulations

AlN is an important III-V wide-bandwidth semiconductor material. Its maximum (ultra-wide) direct bandgap of up to 6.2 eV at room temperature and excellent physical properties make it have great application prospects in the fields of high-power high-frequency electronics and high-efficiency optoelectronic devices. In this paper, based on Computational Fluid Dynamics (CFD), the finite volume method was employed to investigate the process of growing AlN thin films by MNVPE using CFD simulation software for three-dimensional numerical simulation. By optimizing the chamber structure, it was devoted to improving the growth rate and uniformity of AlN thin films. Different thicknesses of porous media were placed in front of the substrate respectively, and the flow field analysis showed that the presence of eddy currents can be effectively suppressed to reduce the pre-reaction, and the best growth effect was achieved when the thickness reached 7 cm. With the increasing of porosity, more gas reached the substrate surface and improved the growth rate of AlN films. Secondly, for the 90° substrate, substrate rotation created a pumping effect and the growth rate was higher with the increase of the rotation speed. At 160 rpm, the growth rate reached 11.29 μm/h and the coefficient of variation decreased to less than 5 %.

Electro-thermal analysis of hybrid fluid through wavy divergent channel

In the bio-medical domains, the transportation of physiological fluids within the human body like chyme movement in the gastrointestinal tract, bolus through the esophagus, blood circulation in the small vessels and heart chambers etc., where the channels are nonuniform in nature. Due to diverse applications of nonuniform channel, in the current mathematical analysis the peristaltic flow of hybrid fluid (containing particular nanoparticles) under an applied axial electric field through the nonuniform channel is presented. To observe hybrid fluid performance, a set of modified hybrid fluid that comprise nanoparticles of titanium dioxide, aluminum trioxide and copper with water as a base fluid is considered in the analysis. Taking into consideration the long wavelength and low Reynolds number assumptions. Poisson-Boltzmann equations are linearized by the Debye-Hückel approximation. Solutions for the axial velocity, average flow rate, pressure gradient, pumping phenomena, heat transfer phenomena and volumetric fraction are obtained analytically. The physical impacts of numerous embedded parameters on the above-mentioned features are argued through graphs which are plotted by Mathematica 11.0 Software. Additionally, the influence of porous medium and nonuniform nature of flow geometry are also discussed in detail. The study could be useful in medical as well as the industrial domains since the electro-osmotic phenomenon is observed throughout the human body where through the osmosis, the body absorbs the nutrients from the food and toxins are removed from the blood stream. Also the nanofluids are widely used in medicines for drug delivery. Also in industries, electro-osmosis has many applications in microchips, biophysics, microfluidics, gas and oil manufacture and separations through the membranes etc.

The Effect of Porous Media on Wave-Induced Sloshing in a Floating Tank

Placing porous media in a water tank can change the dynamic characteristics of the sloshing fluid. Its extra damping effect can mitigate sloshing and, thereby, protect the integrity of a liquefied natural gas tank. In addition, the out-of-phase sloshing force enables the water tank to serve as a dynamic vibration absorber for floating structures in the ocean environment. The influence of porous media on wave-induced sloshing fluid in a floating tank and the associated interaction with the substructure in the ambient wave field are the focus of this study. The numerical coupling algorithm includes the potential-based Eulerian–Lagrangian method for fluid simulation and the Newmark time-integration method for rigid-body dynamics. An equivalent mechanical model for the sloshing fluid in a rectangular tank subject to pitch motion is proposed and validated. In this approach, the degrees of freedom modeling of the sloshing fluid can be reduced so the numerical computation is fast and inexpensive. The results of the linear mechanical model and the nonlinear Eulerian–Lagrangian method are correlated. The dynamic interaction between the sloshing fluid and floating body is characterized. The effectiveness of the added porous media in controlling the vibration and mitigating the sloshing response is confirmed through frequency response analysis.

Effects of grain shape and packing pattern on spontaneous imbibition under different boundary conditions: Pore-scale simulation

Core-scale spontaneous imbibition experiments and numerical simulations have demonstrated that the macroscopic imbibition performance is significantly different under different boundary conditions. However, the detailed pore-scale flow mechanisms behind these phenomena and the influence of porous media's geometric features on the imbibition behavior under different boundaries have not been addressed in depth. In this work, an optimized color-gradient lattice Boltzmann model is applied to simulate spontaneous imbibition in granular media under four boundary conditions. The influence of grain shape and packing pattern on the two-phase interface evolution and the recovery factor during spontaneous imbibition is investigated while fixing different models' porosity, grain number, and size distribution. It is found that the grain shape has little influence on the drainage interface evolution at the initial stage but it has a more significant influence on the imbibition interface during counter-current spontaneous imbibition. The grain packing pattern influences the evolution of drainage and imbibition interfaces and the recovery factor. Spontaneous imbibition with different boundary conditions has different imbibition rates and ultimate recovery factors. The fastest imbibition rate and highest ultimate recovery are obtained under all faces open and two faces open (free) boundary conditions, respectively. This research provides pore-scale insights into the complex dynamic fluid displacement mechanism between the fracture and matrix of fractured oil and gas reservoirs.

Porous medium on unsteady Helical flows of Generalized Oldroyd-B with two infinite coaxial circular cylinders

This article deals with the influence of porous media on Helical flows of Generalized Oldroyd-B between two infinite coaxial circular cylinders .The fractional derivative are modeled for this problem and studied by using finite Hankel and Laplace transforms .The velocity fields founded by using the fundamentals of the series form in terms of Mittag-leffler equation . The research focused on the parameters like (permeability parameter z ,fractional parameters(𝛼 , 𝛽) , relaxation 𝜆1 , retardation 𝜆2 , kinematic viscosity v , magnetic parameter M and time t) which effected on the velocity field u and w. MATHEMATICA package used to study and analyze the above variables by drawing many graphs .

Experimental determination of deviation factor of natural gas in natural gas reservoir with high CO2 content

The deviation factor of natural gas is a coefficient to quantitatively describe the deviation degree between real gas (natural gas) and ideal gas. Generally, the deviation factor of natural gas is measured in PVT cell without considering porous media. However, when natural gas is in underground porous media reservoir, due to the adsorption of porous media, the deviation factor of natural gas in porous media deviates from that measured in conventional PVT cell. Moreover, compared with other gases, CO2 has stronger adsorption capacity. Therefore, in porous media, the deviation factor of natural gas considering the adsorption of porous media is quite different from that measured in conventional PVT cell. In this paper, simulating the isothermal mining conditions in gas reservoir,the deviation factor of natural gas with different CO2 content considering the influence of porous media under different pressure isothermal conditions is studied by using the test of designed sand filled long slim tube in series. And under the same conditions, the deviation factor is compared with that of conventional PVT. The experimental results show that under the same conditions, due to the adsorption of porous media, the deviation factor measured in porous media is smaller than that measured by PVT cell without considering porous media.

Porous Media in the Simulation of Greenhouse Crops Using the Naïves Bayes EM Algorithm

The porous media approach has become more popular thus, it solves the equations of motion and energy numerically and therefore obtains detailed distributions of temperature and airspeed. However, those models are not allowed to forecast the relationships between the porosity of the volume of the crop with respect to the variables that comprise the climate in natural ventilation greenhouses at the same time in terms of probability. A porous media model of the crop and its approximations were developed and analyzed through non-supervised Bayesian Networks clustering, with the aim of determining the influence of porous media in function to the density crop, over the climate conditions in a natural ventilation greenhouse. Also, a naïve Bayes model unsupervised by the EM algorithm, initialized with random parameters was developed. The resulting model maximized the likelihood of the training data set. The relationships between the pressure drops in the flow limits at the crop were established. Porosity is directly influenced by humidity, temperature and slowly to CO2 concentration. Solar radiation, speed air and slowly the height are inversely influenced with the porosity. Naïve Bayes EM application to a CFD model has been providing a greater understanding of the interactions between the variables.

Homogeneous-heterogeneous reactions in curved channel with porous medium

Purpose of the present investigation is to examine the peristaltic flow through porous medium in a curved conduit. Problem is modeled for incompressible electrically conducting Ellis fluid. Influence of porous medium is tackled via modified Darcy’s law. The considered model utilizes homogeneous-heterogeneous reactions with equal diffusivities for reactant and autocatalysis. Constitutive equations are formulated in the presence of viscous dissipation. Channel walls are compliant in nature. Governing equations are modeled and simplified under the assumptions of small Reynolds number and large wavelength. Graphical results for velocity, temperature, heat transfer coefficient and homogeneous-heterogeneous reaction parameters are examined for the emerging parameters entering into the problem. Results reveal an activation in both homogenous-heterogenous reaction effect and heat transfer rate with increasing curvature of the channel.

Thermal and hydrodynamic performances of MHD ferrofluid flow inside a porous channel

MHD mixed convection heat transfer inside a rectangular porous channel under the effects of constant and alternating magnetic fields has been experimentally investigated. Deionized water containing magnetite particles flows through the channel filled with copper foam as a porous media. A constant heat flux condition is imposed on the top and bottom plates of the channel, while the side walls are adiabatic. Experiments were carried out at Gr=7.31×106 and 373≤Re≤1186. Influence of porous media, volume fraction of ferrofluid (ϕ=0.5%, 1%, 1.5%), Reynolds number and magnetic field intensities and frequencies (B=250, 450G and f=5, 10Hz) on the characteristics of heat transfer and hydrodynamic are studied. The experimental results revealed that the copper foam has a significant effect on the thermal and hydrodynamic performances of the channel due to heat spreading through the copper matrix, better mixing of the fluid and extending the heat transfer area. It was observed that employing ferrofluid with different volume fractions increases both heat transfer rate and pressure drop because of thermal conductivity and viscosity increment, respectively. Applying constant magnetic field causes aggregation of nanoparticles in the area where the magnetic field is applied and consequently, heat transfer and pressure drop increase. Moreover employing alternating magnetic field further increased the heat transfer rate due to more intensified disturbance of the thermal boundary layer and improvement of the nanoparticles migrations. The alternating magnetic field reduced pressure drop because of the periodic magnetic forces, leading to enhanced overall performance of the channel.

Influence of porous media on the performance of hybrid PV/Thermal collector

Porous media play an important role in the process of storage energy. In this paper, the influence of porous media on the performance of a double pass hybrid PV/thermal air collector was achieved by building an experimental set-up for this purpose. The study showed that using porous media expanded the area of heat transfer and thus increased the thermal efficiency and temperature of the exit air from the hybrid solar collector. The compound efficiency was increased (3%) after using the porous medium in the lower ducts of the double-pass hybrid collector. At the same time, the pressure drop was increased after using the porous media.In this analysis, it was concluded that the hybrid solar collector with porous media and glass cover is more thermally efficient than the other design form. The results showed a rise in the electrical efficiency with the increase of the fluid flow rate. This increase in the value of the electrical efficiency was due to the higher volumetric air flow which enhanced the PV panel cooling. Also, the results displayed that fixing a glass layer on the hybrid collector caused the rise in thermal efficiency and reduction in the electrical efficiency of the hybrid collector. The highest value for the daily thermal efficiency was 80.23% in the collector that used porous media and glass cover, while the higher value for the thermal efficiency was 51.25% without porous media and glass cover. Also, the highest value for the daily electrical efficiency was 8.7% in the collector that used porous media and the higher value for the daily electrical efficiency was 10.91% without porous media and without glass cover. The use of porous media and glass cover in the hybrid system is a desirable option when using the hybrid system for electrical generation only.

Minimum miscibility pressure estimation for a CO2/n-decane system in porous media by X-ray CT

Accurate determination of gas–fluid miscibility conditions is important to optimize the displacement efficiency during CO2-enhanced oil recovery. This paper presents a new technique to investigate the phase behavior and to estimate the minimum miscibility pressure (MMP) of a CO2/n-decane system using an X-ray computerized tomography (CT) scanner. CT scans of the CO2/n-decane system are taken at various pressures during the experiments. The image intensity values taken from the CT images have a linear relationship with the densities of the measured objects; therefore, we can estimate the miscible point of CO2 and n-decane because the difference between the intensity values for each phase decays to zero as the pressure increases toward the MMP. This paper provides experimental evidence for the validity of the new CT method by comparing the results with previous studies and presents an application of the method to investigate the MMP of the CO2/n-decane system in porous media. Additionally, the influence of porous media on the equilibrium state when the CO2/n-decane system is close to miscibility is discussed.

Carbon Dioxide Sequestration: Influence of Porous Media on Hydrate Formation Kinetics

In the present study, CO2 sequestration by hydrate formation in porous sediments has been discussed. Two siliceous materials with high porosities, pumice and fire hardened red clay (FHRC), have been used as packing materials in a fixed bed setup to study hydrate formation kinetics. The results obtained using the aforementioned materials were compared with those obtained using silica sand and quartz. Carbon dioxide hydrate formation kinetics was studied at 3.0 MPa pressure and 274 K temperature. Two different types of experiments were conducted: (a) using a constant volume of water and (b) maintaining a constant bed height. These experiments were conducted using the different porous media individually as packing materials. It was observed that pumice as the porous medium showed better hydrate formation kinetics resulting in 46 mol % water to hydrate conversion in 5 h. Moreover, kinetics was enhanced with decrease in the bed height of pumice; this suggests that at field scale adaptation of CO2 sequestration...

Influence of porous media on intrusion rate into water distribution pipes

Research Article| October 08 2013 Influence of porous media on intrusion rate into water distribution pipes Yan Yang; Yan Yang 1College of Civil Engineering and Architecture, Zhejiang University, A810 Anzhong Building, Hangzhou 310058, China Search for other works by this author on: This Site PubMed Google Scholar Tuqiao Zhang; Tuqiao Zhang 2College of Civil Engineering and Architecture, Zhejiang University, A511 Anzhong Building, Hangzhou, 310058, China Search for other works by this author on: This Site PubMed Google Scholar David Z. Zhu David Z. Zhu 3College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China and Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 2W2 E-mail: david.zhu@ualberta.ca Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2014) 63 (1): 43–50. https://doi.org/10.2166/aqua.2013.213 Article history Received: June 12 2013 Accepted: September 03 2013 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Yan Yang, Tuqiao Zhang, David Z. Zhu; Influence of porous media on intrusion rate into water distribution pipes. Journal of Water Supply: Research and Technology-Aqua 1 February 2014; 63 (1): 43–50. doi: https://doi.org/10.2166/aqua.2013.213 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Untreated water can intrude into water distribution systems through pipe leaks and cracks when negative pressure events occur inside drinking water pipelines. The orifice equation is typically used for calculation of intrusion flow rate, which ignores the impact of the soil surrounding the pipeline. This paper presents the results of an experimental study on the effect of porous media surrounding pipelines and the flow Reynolds number on intrusion flow rate for a circular orifice. The porous media, orifice size, and flow regime affect the discharge coefficient of the orifice equation. A new expression was suggested for predicting the intrusion flow rate. A discontinuity in the discharge coefficient was also found at a large Reynolds number. The effect of the pipe curvature on the discharge coefficient was found to be insignificant. contaminant intrusion, discharge coefficient, orifice equation, porous media, water distribution system This content is only available as a PDF. © IWA Publishing 2014 You do not currently have access to this content.

Empirical investigation of two designs of incline solar water desalination system

Empirical investigation of two designs of incline solar water desalination system This paper presents an experimental investigation of two incline solar water desalination (ISWD) systems. One design uses spray jets for spraying water onto the absorber plate, while the other uses a longitudinal slot for getting the inlet water on the absorber plate. The first ever ISWD system constructed and tested by Aybar et al (2005) used the longitudinal slot with a maximum daily production of 2.995 kg/m2 day. The Aybar et al design produced 3.4 kg/m2-day while the new design produced 6.41 kg/m2-day for wick on absorber plate system day during the hottest months in Famagusta (July-August 2010). Also tested was the influence of porous media (wire mesh), wick on the absorber plate. The effect of number of spray jets used in the system on the daily productivity and efficiency of the systems were also investigated.

Lattice Boltzmann simulation of natural convection in porous media

This paper confirms the reliability and the computational efficiency of the lattice Boltzmann method in simulating natural convection in porous media at the representative elementary volume scale. The influence of porous media is considered by introducing the porosity to the equilibrium distribution function and by adding a force term to the evolution equation. The temperature field is simulated by a simplified thermal energy distribution function which neglects the compression work done by the pressure and the viscous heat dissipation. A comprehensive parametric study of natural convective flows is carried out for various values of Rayleigh number, of Darcy number, and of porosity. The comparison of solutions between the present model and earlier studies shows good quantitative agreement for the whole range of Darcy and Rayleigh numbers.

209 格子ボルツマン法を用いた多孔質体内の熱流動解析(S37-1 CFDの新展開(1),S37 CFDの新展開)

The lattice Boltzmann method (LBM) is adopted to simulate natural convection in porous media at the representative elementary volume (REV) scale. The influence of porous media is considered by including the porosity into the equilibrium distribution function and by adding a force term to the evolution equation. The temperature field is simulated by a simplified thermal energy distribution function which neglects the compression work done by the pressure and the viscous heat dissipation. A comprehensive parametric study of natural convective flows is carried out for various values of Rayleigh number (Ra), of Darcy number (Da), and of porosity (ε). The results of the LBM indicate that the average Nusselt number (Nu) increases with the fluid Rayleigh number, the Darcy number, or the porosity of the medium. The comparison with those of earlier studies shows good quantitative agreement for the whole range of Darcy and Rayleigh numbers. It is reasonably concluded that the lattice Boltzmann method may have applicability to simulate natural convection in porous media.

Influence of porous medium and NAPL distribution heterogeneities on partitioning inter-well tracer tests: a laboratory investigation

The inter-well partitioning tracer test seemingly provides an attractive way of investigating the presence of non-aqueous phase liquids (NAPLs) in aquifers. Although the feasibility of this rather new technique has been tested in the field, only few laboratory experiments have been performed to test its validity at scales greater than the column scale. In this study, a partitioning tracer test was conducted in a nominally two-dimensional, intermediate-scale flow cell containing a tetrachloroethene (PCE) spill. Tracer breakthrough curves were obtained at 14 sampling ports and an extraction well containing three outlets. Estimated PCE contents resulting from the tracer technique were compared to PCE saturations obtained at 800 locations by gamma radiation. An inverse procedure, based on the two-site, non-equilibrium convection–dispersion equation, was used in addition to the moment method for sampling port data analysis. Although the inverse procedure produced slightly better results than the moment method, the tracer technique generally underestimated the amount of DNAPL contained in our aquifer model. Notably, our results showed that the pooled part of the DNAPL spill was not detected. This was attributed to the low aqueous phase permeability within the DNAPL pool in combination with rate-limited partitioning of the tracers into the DNAPL. Our analysis indicate a general difficulty for the tracer technique to detect NAPL located in pools or large lenses.

Influence of Porous Media, Airflow Rate, and Air Channel Spacing on Benzene NAPL Removal during Air Sparging

To study the effects of porous media type, airflow rate, and air channel spacing on NAPL removal, air sparging of a benzene NAPL was performed in a lab-scale reactor with two isolated vertical air channels on either side of the NAPL. Experimental conditions included three discrete air channel distances, three types of saturated porous media, and five airflow rates. Benzene NAPL removal efficiency was shown to increase from 7.5% to 16.2% with increasing porous media mean particle size over the 168 h of operation. Initial change in the airflow rate had an effect on contaminant removal rate, but further change in the airflow rate had little effect. Benzene NAPL removal efficiency was shown to decrease with increasing channel spacing, but the mere presence of air channels was shown to suppress lateral contaminant migration. Benzene removal efficiency was shown to be highly correlated with the mean particle diameter, the square root of the uniformity coefficient, and the inverse of the square of the distance between the NAPL and the air channel.