Porous Pipe Research Articles

Entropy generation analysis of unsteady MHD nanofluid flow in a porous pipe

This article presents a numerical investigation into the entropy production of nanofluids flowing through a porous medium in a permeable conduit, focusing on water-based solutions containing Titanium Carbide (TiC) and Silicon Carbide (SiC) nanoparticles. These nanoparticles are selected for their heat transfer properties. The flow system's governing equations are developed and solved using the Runge-Kutta-Fehlberg method. The study examines the influence of key nondimensional parameters, including the solid volume fraction of nanoparticles, radiation parameters, and Reynolds number, on temperature, velocity profiles, and entropy generation. The results show that Silicon Carbide-water nanofluids perform efficiently in terms of heat transfer and entropy minimization. Additionally, Silicon Carbide exhibits low skin friction at the pipe wall, with this effect increasing as the solid volume percentage of nanoparticles rises. The study also indicates that irreversibility due to heat transfer becomes more significant near the pipe wall as the solid volume fraction decreases and increases with higher radiation parameters and Reynolds number. These findings are presented graphically and in tabular form to illustrate the physical significance of the problem.

Preliminary Validation of Persulfate Delivery Through Porous Pipe in the Vadose Zone: A Two-Dimensional Sandbox Experiment

ABSTRACT When remediating contamination in the vadose zone, which is a potential source of continuous groundwater and surface water pollution, technical challenges are often encountered. In this study, the feasibility of delivering sodium persulfate (SPS) oxidant to unsaturated soils was explored by integrating porous pipes, commonly used in agriculture, with in-situ chemical oxidation (ISCO). An evaluation of the operating characteristics of the pipe determined a recommended influent rate of < 0.1 L min−1 and an initial influent water pressure < 20 kPa to prevent percolation pore enlargement. Two-dimensional sandbox experiments revealed that pulse infiltration at an influent rate of 0.05 L min−1 was effective in creating matrix flow and lateral movement, minimizing preferential flow induced by continuous infiltration. Application of SPS (10% by wt.) under these conditions resulted in approximately 90% wetting of the sandbox area SPS flow at the experimental time that infiltrated from the pipe. After a 14-d post infiltration resting state, residual SPS concentrations ranged from 6,000 -12,000 mg/kg in soil, with soil pH levels of 3–4, ORP around 600 mV, and 40–60% decreases in soil organic carbon. This developed method helps retain the oxidant and promote chemical reactions, making ISCO a viable option for remediating unsaturated soil contamination.

English

English

Study of pulsating flow of viscous two-phase media in a flat porous pipe considering particle gravity force

This paper examines the issues of unsteady pulsating motion of a viscous two-phase medium in a flat porous pipe taking into account the gravity of a solid particle in a two-dimensional formulation. Changes in the longitudinal velocity profiles of mixtures and the distribution of the volumetric content of the carrier and solid phases in a flat pipe, as well as the rate of liquid infiltration, the distribution of pressure and the volumetric content of the carrier and solid phases in pipes with porous walls have been studied.

THE STUDY ON THE IRREGULARITY OF WATER COLLECTION AND DISTRIBUTION BY POROUS PIPES IN FREE-FLOW WATER MOVEMENT

One of the main utilities used to obtain drinking water in households and drinking water supply in towns are filters with drainage distribution and diversion systems in their main structural elements. The filters are equipped with porous pipes for distributing and collecting water to increase efficiency and reliability. Therefore, obtaining reliable methods for their calculation is of scientific and practical interest. The article notes that water in distribution and collection pipelines moves with a variable flow rate along the way. Moreover, the inflow or outflow of water depends on the pressure variable along the length of the pipe. If the movement is free-flowing, it depends on the variable water level. While for porous pipes, this movement is continuous. The subject of fluid moving with a variable flow rate has been studied by many authors; however, the dependences obtained in those cases mainly concerned perforated pipelines and open trays. The authors study the operation of a porous pipe under the conditions of free-flow movement, which is described by two equations, the movement of fluid inside the pipe and the movement of fluid through the pipe's walls. The article indicates the complexity of this problem. Namely, the fact that these equations are interconnected. That is, the fluid flow through the pipe walls depends on the depth of the water layer in the pipe, which is determined by the equation of motion inside the pipe. Similarly, the law of depth change is defined, particularly by the laws of the inflow. A mathematical model was obtained during the investigation of the uneven distribution and collection of water by a porous pipe. Based on this model, an approximate calculation method was developed, which makes it possible to get the value of the average flow depth in the pipe from the critical depth of water installed at the end of the pipe. To simplify the calculations, the article gives the corresponding nomograms. The validation of the model was carried out on an experimental setup. The analysis of the experimental data showed good correspondence to the calculation results performed according to the approximate method, i. e. the deviation of the flow depth in the middle section does not exceed 1.5%.

Evaluation of Thermo-diffusion and Diffusion-thermo Phenomenon on the Reactive Micropolar Fluid Motion Over an Extending Device

This articles evaluates thermo-diffusion and diffusion-thermo effects on the motion of hydromagnetic reacting micropolar fluid along an elongated surface with lateral mass flux in porous media. This kind of study includes heat and mass transport of fluids which finds regular applications in various fields of engineering and sciences like porous pipe design, groundwater hydrology, brain blood flow, etc. This body of work also presents a report on thermophoretic phenomenon together with viscous dissipation and heat source. The model equations are firstly transformed from partial derivatives to ordinary ones by the use of some similarity quantities and subsequently tacked numerically. The nonlinearity of the involving equations has compelled the use of stable Runge-Kutta-Fehlberg approach with shooting technique to provide the needed solution. To emphasize and discuss the influence of the primary governing parameters impacting on the flow fields, a variety of graphs have been sketched out and discussed qualitatively. Verification of the numerical code with existing data in literature shows an excellent agreement as checked under limiting conditions and presented in the table. It is evidently shown that the material quantity causes the fluid motion to accelerate whereas the suction term reduces the speed of fluid. Both thermo-diffusion and diffusion-thermo strengthen the heat distribution in the system while the concentration profile declines with chemical reaction.

Investigating the Effect of Saturated Hydraulic Conductivity in Porous Pipe Irrigation System and Comparing to Other Parameters

A subsurface porous pipe irrigation system has been widely used, water seeps from the porous pipe into the soil. Such systems can carry out both conveyance and seepage in the same time. Hence by this research, it is investigated the effect of saturated hydraulic conductivity of the porous pipe on the movement of soil moisture contents by using five values of 0.05, 0.075, 0.1, 0.125, and 0.15 cm/hr for the pipe. The pipe is installed at a depth of 15 cm with 6 cm as the outer diameter. Then water heads of 25, 50, and 75 cm are applied for 2 hours as an operation time. Preparations in the HYDRUS/2D are done and all movements of soil moisture contents are recorded with time. Empirical functions are found with the collected data in both sides of horizontal and vertical directions with an average relative error value not exceeds 4 % and with coefficients of determination more than 0.97. Therefore, these empirical functions are well fitted and can be used as an indicator in designing system of subsurface porous pipe irrigation.

Stability analysis of dual viscous flows saturating a vertical porous pipe

The linear stability analysis of a mixed convection viscous flow in a vertical porous pipe is here investigated. The contribution of viscous heating is assumed to be non negligible. A fully developed flow regime is assumed for the basic state. The local balance equations for this state display dual stationary solutions. The dual branches of stationary solutions are determined numerically. Since the pipe is characterised by an isothermal lateral surface, the viscous heating is the sole cause of the buoyancy force. In order to investigate the stability of the basic dual solutions, small amplitude disturbances with the form of normal modes are superposed to the basic state. The solution of the eigenvalue problem obtained allows one to determine the growth rate associated to both the basic solution branches. The sign of the growth rate determines whether the particular basic solution is stable or unstable.

Role of Chemically Magnetized Nanofluid Flow for Energy Transition over a Porous Stretching Pipe with Heat Generation/Absorption and Its Stability

The laminar movement in an expanding and contracting permeable pipe or surface has recently attracted the attention of many scholars owing to its application in engineering and biological processes. The objective of the current study is to examine the influence of chemical processes on magnetized nanofluid flow over extending or shrinking permeable pipes with a heat reservoir. The flow equations are renovated into first ODEs by introducing the new variable and then numerically solved by RK4 with a shooting procedure. The effect of emerging factors on the flow features is observed using graphs and elaborated in detail. From the analysis, the temperature is raised when the heat source is increased in both cases of wall expansion or contraction but declines in the case of heat sinks. In the case of a heat source, the temperature rises as the Hartmann and Prandtl numbers are enhanced, but in the case of a heat sink, the temperature falls. In the presence of heat sinks and injections, when the thermophoresis factor is increased, the concentration of nanoparticles is increased in both wall expansion and contractions. In both situations of wall extension or contraction, along with injection, the concentration of nanoparticles is a decreasing function of Nb, while the concentration of nanoparticles is an increasing function in the case of a heat source. Additionally, for the confirmation of the RK4 code, the total average square residue error and average square residue error are also presented. For the stability analysis, the current work is compared with published work, and excellent agreement is established. The novelty of the present study is to investigate the effect of chemical reaction on magnetized nanofluid flow over extending and shrinking porous pipes with heat generation and absorption.

Enhancement of Double-Pipe Heat Exchanger Effectiveness by Using Porous Media and TiO2 Water

In this paper, the rate of heat transfer by forced convection in a counterflow heat exchanger, at turbulent flow conditions were investigated experimentally, using porous media and TiO2 Nanofluid to observe the behaviour of heat transfer with flow rate and volume concentration of nanoparticles t enhance heat transfer through it. 3 mm Steel balls (ε=39.12%) as a porous media completely filled to the inner pipe (core pipe). The cold and hot water are used as working fluids through the inner and outer pipes. Then using, the TiO2 nanofluid instead of cold water flowing through the porous pipe to enhance heat characteristics. The effects of operating parameters include flow rate (4 LPM, 6 LPM, and 8 LPM), Reynolds number between (3000 – 7000), and nanoparticle volume fraction (0.001, 0.002 and 0.003) on Convective heat transfer co-efficient and Nusselt number. Effective thermal conductivity is increased when the nanoparticle volume fraction is increased. The heat transfer coefficient increases with decreasing nanofluid temperature, but the heating fluid's temperature has no significant effect on the nanofluid's heat transfer coefficient. The results show that porous media and TiO2-based nanofluid's improve heat transfer at flow rate of 4 LPM by 35.4% and improve NTU and effectiveness at flow rate of 4LPM by 12.4%, and 24%, respectively, when compared to pure water without porous media. This improvement in thermophysical properties yielded high heat transfer of heat exchangers used in process industries.

Entropy analysis of the MHD Jeffrey fluid flow in an inclined porous pipe with convective boundaries

Entropy analysis of the MHD Jeffrey fluid flow in an inclined porous pipe with convective boundaries

On Sources of Damping in Water-Hammer

Various potential causes of damping of pressure waves in water-hammer-like flows are discussed, with special attention being paid to their qualitative influences on measured pressure histories. A particular purpose is to highlight complications encountered when attempting to interpret causes of unexpected behaviour in pipe systems. For clarity, each potential cause of damping is considered in isolation even though two or more could exist simultaneously in real systems and could even interact. The main phenomena considered herein are skin friction, visco-elasticity, bubbly flows and porous pipe linings. All of these cause dispersive behaviour that can lead to continual reductions in pressure amplitudes. However, not all are dissipative and, in such cases, the possibility of pressure amplification also exists. A similar issue is discussed in the context of fluid–structure interactions. Consideration is also given to wavefront superpositions that can have a strong influence on pressure histories, especially in relatively short pipes that are commonly necessary in laboratory experiments. For completeness, attention is drawn towards numerical damping in simulations and to a physical phenomenon that has previously been wrongly cited as a cause of significant damping.

Nonlinear nonplanar dynamics of porous functionally graded pipes conveying fluid

This paper aims to investigate the three-dimensional (3-D) nonlinear dynamics of a porous functionally graded (FG) pipe subjected to lateral harmonic excitation. Material properties of the porous pipe are graded across the radius in a power-law distribution form. Based on the Euler–Bernoulli beam theory, the nonlinear equations of motion are derived employing the Hamilton’s principal to achieve third-order accuracy with the fluid-related loads associated with the bending–torsional vibration. The new nonlinear model, consisting of three strongly coupled nonlinear partial differential equations, is discretized into second-order ordinary differential equations via Galerkin method. Subsequently, the pseudo-arclength continuation technique together with a direct time-integration method are employed to perform nonlinear static and dynamic responses of this gyroscopic system. Numerical parametric investigations are conducted to assess the significant effects of different parameters on the resonant dynamic behavior of system, with special focus on the modal interaction that could lead to multiple coexisting solutions including planar and nonplanar motions. Moreover, the nonplanar resonance behavior is revealed that the influences of structural symmetries and symmetry-breaking effects on bifurcations and instabilities in comparison to the previously classical planar resonance behavior.

Modification of Micro Bubble Generator Type Orifice Porous Pipe with Distributor Pipe for Fish Water Pool

Modification of Micro Bubble Generator Type Orifice Porous Pipe with Distributor Pipe for Fish Water Pool

Physiological studies on eggplant (Solanum melongena) grown under drought conditions

Field experiment was conducted during the two growing seasons of 2019 and 2021, at Dokki region, El-Giza Governorate, Egypt, in order to investigate the effect of deficit irrigation (DI) treatments: 100% (control), 70% and 50% of ETo (Reference evapotranspiration) and two irrigation systems: Surface drip irrigation (SDI) and Subsurface irrigation (SSI)porous pipe (20.0cm soil depth) on vegetative growth, chemical constituents, fruit yield and quality of eggplant plants (Cultivars : “Classic” “Swad Eleil”). Results revealed that, DI treatments significantly decreased the vegetative growth, total yield ,marketable yield, leaf relative water content (LRWC) and membrane stability index (MSI) of eggplant plants, compared to control treatment (100% ETₒ). While, water stress treatments improved leaves proline content, alkaloids and irrigation water use efficiency (IWUE). Using SSI (porous pipe) system significantly increased plant height, fresh weight, total yield, marketable fruit yield of eggplant, LRWC and MSI, “Classic” cv had the highest total yield and total marketable yield under the subsurface irrigation system compared to “Swad El-Layl”cv. Regarding, the effect of interaction between DI treatments and irrigation systems, the results illustrated that application of irrigation water with 100% ET0 by SSI system produced the highest significant values of vegetative growth, fruit yield.

Experimental investigation on bubbles generated by porous pipes

Experiments were carried out to determine the characteristics of bubbles originated in still tap water by a porous polyethylene pipe used as an air sparger. Local bubble populations were sampled at various regions of the pipe cross-section and at various air flow-rates to assess the effects of the surface local orientation and flow conditions on bubble dimensions. It was discovered that at the bottom of the pipe the size distribution of the bubbles is almost invariant with respect to air flow. On the contrary, at other locations bubble dimensions increased with the air flow-rate and the surface inclination. Statistical analyses proved that the distributions of bubble diameters and their mean values are better modeled by the Gamma distribution than the Log-Normal distribution. Local populations were merged to get the corresponding global populations. It was discovered that the bubbles from the upper half of the pipe cross-section have a higher weight in determining the properties of global populations. Global bubble populations from the whole cross-section of the pipe were directly measured at low air flow-rates. Their mean diameters were used to validate the merging procedure. Two Koide-like correlations were successfully implemented to model as a function of the Froude and Weber numbers the dimensionless mean diameter and the dimensionless Sauter mean diameter of the global bubble populations. The Froude and Weber numbers were computed based on the flow of air through the porous wall, which was successfully modeled with the Forchheimer equation for compressible fluids.

Extending the Validity of Basic Equations for One-dimensional Flow in Tubes with Distributed Mass Sources and Varying Cross Sections

Flow problems are solved using so-called fundamental equations and the corresponding initial and boundary conditions. The fundamental equations are the motion equation, the continuity equation, the energy conservation equation, and the state equations. In our paper, we extend the validity of the equation of motion used to describe one-dimensional, steady-state tubular flow to a case in which the mass flow of the medium changes along the tubular axis during the flow. Such flows occur in perforated and/or porous pipes and air ducts. The research in this direction was motivated by the fact that the extension and formulation of the equation of motion in this direction has not been carried out with completely general validity. In the equation of motion used to solve the problems, the isochoric and isotherm nature were assumed. In our paper, we present fundamental equations that formulate differential equations to describe polytrophic and expanding flows.

Analytical Solution of Oscillatory Stokes Flow in a Porous Pipe with Spatiotemporally Periodic Suction/Injection

The study presents a generalized analytical solution of the laminar, oscillatory, creeping flow of an incompressible Newtonian fluid in a porous circular pipe with spatiotemporally periodic suction/injection at the wall. The analytical solution is examined for a variety of values of the dimensionless parameters, namely the Womersley number and the dimensionless suction/injection number.

Numerical study on influence of water based hybrid nanofluid and porous media on heat transfer and pressure loss

The performance augmentation of the heat exchangers is a deal between heat transfer improvement and pressure loss penalty. There is no study investigating this deal as the thermal performance index of the heat exchangers filled by hybrid nanofluid and porous media. The thermophysical properties of TiO2–Al2O3/water are available in the literature, but no study is dedicated to evaluating the flow characteristics of such a hybrid nanofluid, especially in a porous material. This paper is intended to explore the heat transfer and pressure loss of a turbulent convective flow of hybrid nanofluid (TiO2–Al2O3/water) and porous media in a double-pipe heat exchanger with a counter flow. Hot water flows in an annular pipe to warm cold nanofluid flow in an inner pipe. The effect of two porous media is examined for inserting in the inner pipe. Hybrid nanofluid increases the heat transfer (maximum 6%) and pressure loss (maximum 11%). The thermal performance index of the hybrid nanofluid in the aluminum porous media is less than 0.6, while this for the copper media is more than 1. Correlations for the calculations of the Nusselt number and friction factor of the turbulent hybrid nanofluid flow in porous media are missing in the literature. So, for the first time, equations were proposed for finding the Nusselt number and friction factor of the hybrid nanofluid in both empty and porous pipes.

Novel thermal treatment model to decontaminate airborne SARS Cov‐2 virus for residential and commercial buildings

In the COVID‐19 pandemic, control of airborne virus transmission is exceptionally challenging as it is attached to suspended particles in the air and stays for an extended time. Air contaminated with airborne viruses holds a substantial risk for household transmission. In this study, a novel thermal treatment system is modeled based on porous heating for the decontamination of airborne SARS‐Cov‐2. The model includes an air heating domain, insulated chamber, buffer tank and heat exchanger. The airborne SARS‐Cov‐2 is decontaminated when passing through a porous heat pipe and the insulated chamber for an anticipated dwelling period of more than 5 min at 105°C and further stored in a buffer tank for natural cooling. The obligatory decontaminated air is allowed in the residential space under ambient conditions passing through a heat exchanger. The numerical investigation of the porous pipe model at different L/D ratios with altered porosities aims to establish the best‐performing porous domain. Besides this, the buffer tank is intended to maintain buffer storage of the treated air and significant natural cooling before passing to the heat exchanger. A solar PV module is proposed to meet the prerequisite energy requirements of the equipped devices.