Horizontal Walls Research Articles

Magnetohydrodynamic double-diffusive mixed convection in a curvilinear cavity filled with nanofluid and containing conducting fins

This work numerically analyzes the mixed convective double diffusion of Fe3O4-water-based nanofluid in a tilt curvilinear lid-driven cavity studied under the effect of an inclined magnetic field. The horizontal upper wall is at a lower thermal and concentration gradient and moves toward the right. The side vertical walls and bottom walls kept adiabatic. Furthermore, two numbers of conducting fins are affixed to the inclined walls at high temperatures and concentrations. The finite element approach is implemented to analyze the considered variables: Richardson number (Ri), Hartmann number (Ha), Reynolds number (Re), Lewis number (Le), buoyancy ratio (N), magnetic inclination angle (α), nanofluid volume fraction (ϕ) as well as the fins length on the heat and mass transport phenomena. The results showed that the Nuavg and Shavg increase by increasing Reynolds number, the nanoparticles volume concentration, and the fin length, while they decrease by increasing Hartmann number. When Ri is small, Nuavg rises with the increasing magnetic field inclination, but when Ri is high, the inclination angle works adversely. On the other hand, the Shavg increases with the rise of the magnetic field inclination for all Ri values. It can be seen also, when Lewis number increases, the Nuavg and Shavg values increase with increasing Ri and magnetic inclination angles.

Numerical study of periodically heated wall effect on natural convection in an enclosure

The present numerical study focuses on sinusoidal heating and aspect ratio effects on heat flow of free convection of fluid inside the enclosure. The side walls are maintained at ambient temperature and the middle horizontal wall that divides the enclosure evenly is heated to sinusoidal temperature and the other horizontal walls are adiabatic. The numerical solution of the transport equations is done by the finite difference method to determine the heat transfer and thermal penetration with respect to aspect ratio, sinusoidal frequency and Rayleigh number. The numerical results of heat and fluid flow in the range of controlled governing parameters such as Rayleigh number (Ra = 105), sinusoidal frequency (1 ⩽N⩽ 4 ) and aspect ratio (0.2 ⩽A⩽ 4) are analysed in terms of streamlines, isotherms, heat penetration length and Nusselt number. It has been found that the 100% thermal penetration in the upper part of the enclosure of the aspect ratio A = 1 is obtained on continuous heating, while in the lower section, the maximum thermal penetration is limited to 98%, which is obtained on non-continuous heating in the enclosure of aspect ratio A = 0.2, 0.5.

Numerical Study of Tsunami Force on Superstructure of Offshore Rigid Frame Box Girder Bridge

Offshore bridges need to bear complex wave and current loads and face the threat of extreme loads such as tsunamis. Potential tsunamis will have disastrous effects on coastal areas. Compared with conventional beam bridges, there are few studies on rigid frame box girder bridges. In this paper, based on a continuous rigid frame box girder bridge in the offshore area, the parameters of tsunami impact force are analyzed. First, based on Stoke theory and water level in the storage area, the water level in the static water area and quasi stable area in the dam break wave working conditions are obtained, and 12 kinds of dam break wave working conditions are preliminarily proposed to be used for the background bridge. Then, according to the determined simulation working conditions, the box girder dam break impact numerical model is simulated. According to the calculated results, the stress characteristics of the box girder under the tsunami impact are described in the way of time history stage division, and on this basis, The stress mechanism is analyzed from the whole level and local level. The results show that on the whole level, the variation of horizontal force and vertical force with time can correspond to the variation of dam break flow around the box girder. At the local level, the horizontal wall boundary bears the vertical force, the vertical wall boundary bears the horizontal force, and the inclined wall boundary bears both the horizontal force and the vertical force. In addition, negative pressure is the cause of suction on the wall boundary. It provides a reference for the calculation and analysis of tsunami load of offshore rigid frame box girder bridges, the identification of bridge failure modes and the formulation of protective measures.

Thermal analysis of ferromagnetic nanofluid flow in a channel over a dimpled cavity

The water-based nanofluid analysis of a ferromagnetic fluid flow in a channel has been conducted over a dimpled cavity. The horizontal flat walls are assumed to be adiabatic, whereas the dimpled part and the inner rectangular-finned-shaped obstacle are heated. The system of Partial Differential Equations (PDEs) along with boundary conditions have been solved via Galerkin Weighted Residual Finite Element Method. To predict the streamlines isotherms, local and average Nusselt numbers, all the simulations are performed for various Reynold and Hartmann numbers. High Reynolds numbers, results in significant improvement in heat transfer at the dimpled surface. It is believed that such investigation might be helpful to make a base for finding the experimental results for mixed convection of ferromagnetic nanofluid problem over a dimpled cavity.

Incompressible impinging jet flow with gravity

In this paper, we investigate steady two-dimensional free-surface flows of an inviscid and incompressible fluid emerging from a nozzle, falling under gravity and impinging onto a horizontal wall. More precisely, for any given atmosphere pressure $$p_{atm}$$ and any appropriate incoming total flux Q, we establish the existence of two-dimensional incompressible impinging jet with gravity. The two free surfaces initiate smoothly at the endpoints of the nozzle and become to be horizontal in downstream. By transforming the free boundary problem into a minimum problem, we establish the properties of the flow region and the free boundaries. Moreover, the asymptotic behavior of the impinging jet in upstream and downstream is also obtained.

Upper bounds for the three-dimensional seismic active earth pressure coefficients

A numerical implementation of the upper-bound theorem of limit analysis is applied to determine two-dimensional (2D) and three-dimensional (3D) active horizontal earth pressure coefficients considering seismic actions through a horizontal seismic coefficient. Results are obtained for vertical wall, horizontal soil, different friction angles of the soil, soil-to-wall friction ratios, horizontal seismic coefficients and wall width-to-height ratios. The few cases for which 3D active earth pressure coefficients are available in the literature using upper-bound methods were used for comparison with the corresponding earth pressure coefficients obtained in this study. This showed a general improvement of these results, which allows expecting a good accuracy for the set of cases studied. The ratios between the 3D and 2D horizontal active earth pressure coefficients are found to be practically independent of the soil-to-wall friction ratio. An equation is proposed for calculating these ratios. This equation can be easily used in the design of geotechnical structures requiring the determination of 3D active earth pressure coefficients.

Effect of rotating cylinder on nanofluid heat transfer in a bifurcating grooved channel equipped with porous layers

The aim of this work is to examine numerically the effect of using a rotating cylinder and porous layers on the forced convection in a bifurcating grooved channel (BGC) filled with two types of nanofluids (MgO-water, SiO2-water). The semi-implicit finite volumes method was used to solve the governing equations. The effects of Reynolds number, nanoparticles volume fraction, and cylinder rotation speed on hydro-thermal performances have been investigated. According to the obtained results, the rotation direction plays a significant role in the formation of vortices at the branching channel, such that when the cylinder rotates clockwise, the vortex occurs in the vertical channel, and it decreases with increasing Reynolds number. Besides, using BGC with a porous medium enhances the heat transfer rate by 52% and 49% at the vertical and horizontal walls of the porous layer, respectively. On the other hand, the heat transfer rate is improved by 2.6% when using MgO nanoparticles compared to SiO2. Therefore, the use of bifurcating grooved channels can improve the thermal performance of various applications in thermal engineering, from fuel cells to electronic cooling.

Visualization of thermo-magnetic natural convective heat flow in a square enclosure partially filled with a porous medium using bejan heatlines and Hooman energy flux vectors: Hybrid fuel cell simulation

The aim of the article is to study the magneto-convective laminar incompressible flow within a differentially heated square enclosure partly filled with porous medium saturated with ionized helium gas in the presence of a transverse magnetic flux, as a model for emerging fuel cell designs. A Darcy model is utilized for porous medium bulk drag effects. Visualization of heat line and energy flux vectors is computed via Bejan's heat line approach and the Hooman energy flux vector method. The horizontal (i.e., bottom and top) wall boundaries are considered adiabatic and impermeable, while the side walls (cold and hot walls) are maintained at different but constant temperatures. The nonlinear coupled conservation equations under prescribed boundary conditions are solved with a finite difference-based vorticity-stream function approach. Appropriate convergence criteria factors are deployed. Furthermore, validation with earlier studies for the purely fluid, non-magnetic case i. e. in the absence of porous medium (Da) and Hartmann number (Ha) effects, is included. A parametric examination of the impact of Rayleigh number (Ra), Darcy number (Da) and Hartmann number (Ha) on temperature contours, heat lines, energy flux vectors and streamline patterns for ionized helium gas (Prandtl number, Pr = 0.71) is conducted. An increment in Hartmann magnetic number decreases the magnitudes of heat lines, suppresses heat transmission in the enclosure and curtails flow circulation. Enhancing the magnetic parameter and Rayleigh number however boosts the average heat transfer rate. Average Nusselt number at the left hot wall is elevated with increasing permeability of the porous medium and Rayleigh number. Mid-section velocities are enhanced in the porous layer but depleted in the non-porous layer of the enclosure with greater Rayleigh number. The simulations find provide some insight into applications in emerging hybrid electromagnetic fuel cells enabling better visualization of the thermal/fluid characteristics via the novel heat flow visualization heat-function and energy flux vectors analogy.

Softwood Anatomy: A Review

Although conifers have very homogeneous wood anatomical structure, some of their features allow differentiation of genera or groups of genera. Softwood anatomy is reviewed and the authors have added contributions, grouping features in five blocks (axial tracheids, axial parenchyma, rays, resin canals and mineral inclusions), with special attention to their diagnostic value at the family, genus or species levels. The discussion addresses, in axial tracheids: growth rings, intercellular spaces, pit arrangement, presence of scalloped tori, torus extensions, notches, warty layer, organic deposits, helical and callitroid thickenings, bars of Sanio and trabeculae; in axial parenchyma: presence or absence, arrangement and type of transverse end walls; in rays: composition, type of horizontal and end walls and cross-field pitting; in resin canals: epithelium and the presence of normal or traumatic resin canals; and in mineral inclusions: presence or absence. Wood structure is characterised at the family level, discussing the main elements that can be used for diagnosis at the genus level or in groups of genera.

Buoyancy-driven flow of magnetohydrodynamic hybrid nanofluids in an open cavity with permeable horizontal walls

The buoyancy-driven flow of hybrid nanofluids in an open cavity is examined in the presence of a magnetic field with an angle to the horizontal axis. The right end of the cavity is open, and the left wall is supposed to be heated. Moreover, the horizontal walls are deemed to be permeable and maintained at ambient temperature. The successive over-relaxation (SOR) technique is applied with the finite-difference method to solve the dimensionless equations. A comparison is executed with formerly published results which provide a good agreement. The grid refinement test has also been carried out to increase the accuracy. Flow and temperature profiles are investigated for the Rayleigh number ( Ra = 104, 105, 106), Reynolds number (Re = 5, 8, 10, 20, 100), Hartmann number ( Ha = 0, 5, 10), concentration of nanoparticles ( φ1 or φ2 = 0.0, 0.05, 0.1), angle of inclination of the magnetic field ( γ = 0°, 30°, 45°), aspect ratio ( A = 1, 2, 3, 4), and suction/blow parameter ( S = −1, 0, 1). Results have been elucidated based on streamlines, isotherms, local Nusselt number ( Nu), and average Nusselt number ( Nuavg). It is noted that the changes in the variables significantly affect streamlines and isotherms. The heat transfer for Cu-Fe3O4/water hybrid nanofluid is higher about 9.98% compared to Fe3O4/water nanofluid and 26.41% compared to water. Furthermore, all other parameters noticeably augment both Nu and Nuavg.

On aerodynamic characteristics of rarefied hypersonic flows over variable eccentricity elliptical cavities

A comprehensive numerical study is performed to reveal the pressure on and heat flux to elliptical cavity surfaces using the direct simulation Monte Carlo method with the influences of elliptical cavity eccentricity, freestream altitude, freestream Mach number, and upstream wall curvature analyzed in detail. The obtained results show that both the high-pressure and high heat flux areas are located around the top lip of the downstream sidewall of an elliptical cavity, and whose peak pressure and peak heat flux are usually tens of times larger than those on the cavity floor; the depth of the high-pressure and high heat flux areas moving to the cavity floor is determined by the half axis length in streamwise, while the width of the two areas is controlled by that in spanwise. Compared with the cylindrical cavity, the elliptical cavity has slightly smaller peak pressure and peak heat flux on the downstream sidewall but has much smaller values on the cavity floor. For two elliptical cavities with the same eccentricity, the one that has a shorter length in streamwise is overall better in reducing the surface pressure and heat flux. The freestream altitude and Mach number also play an important role in affecting the surface pressure and heat flux. In comparison with the horizontal upstream wall, the convex upstream wall reduces the peak pressure and peak heat flux on the downstream sidewall but greatly raises them on the cavity floor, and the concave upstream wall makes them drop sharply in the form of a cliff no matter on the downstream sidewall or on the cavity floor. The physical mechanism behind the wall curvature effect can be explained as follows: surface pressure and heat flux on the downstream sidewall are originated from the violent impact of the external high-speed airstream on the sidewall, while those on the cavity floor are derived from the friction between the rotating vortices inside the cavity and the cavity floor.

Experiments and qualitative analysis by artificial neural network approach on pool boiling of FC-72 on finned surfaces confined by an unheated horizontal wall

Heat transfer measurements were taken during nucleate pool boiling of FC-72 (a saturated liquid utilized for thermal control of electronic components) from extended finned surfaces placed in a horizontal channel. The influence of channel width on boiling behavior for various extended finned surfaces was experimentally investigated. These finned surfaces have an array of uniformly or non-uniformly spaced straight spines with a square cross-section. The fins had a length of 3 mm or 6 mm. Starting from a uniform configuration, for which the width spacing of the spines was 0.4 mm, non-uniform surfaces were obtained by regularly removing some rows of spines. The effects of channel width (0.5–20 mm) and spines distribution were analyzed. The case of an extended unconfined surface was investigated and used as a reference to compare the effect of the confinement. An Artificial Neural Network (ANN) with one hidden layer was trained with the experimental data to predict the heat flux. An optimization algorithm was implemented to calculate the geometry that maximizes the predicted heat flux operating near the maximum temperature limit under different constrictions as fixed fin height or fixed channel width.

A novel star-shaped honeycomb with enhanced energy absorption

To obtain a structure with excellent energy-absorbing ability, based on the traditional star-shaped honeycomb (SSH), a crossed star-shaped honeycomb (CSSH) was designed via evolving the horizontal and vertical walls of the honeycomb into crossed inclined walls. In this paper, the Poisson's ratio and Young's modulus of honeycomb under axial load are theoretically deduced, and a method is proposed to evaluate the deformation stability of honeycomb with the maximum deviation of unilateral horizontal strain (MDUHS). Numerical simulation is employed to verify the theoretical solution, and the in-plane mechanical properties and deformation behavior of CSSH are investigated in detail. The numerical simulation method in Abaqus software was verified by using quasi-static crush test data of 3D printed CSSH specimens. It is found that by changing the inclined angle θ2, CSSH can evolve into a positive Poisson's ratio(PPR), zero Poisson's ratio(ZPR), or negative Poisson's ratio structure(NPR), and Young's modulus is very sensitive to the difference between the opened angle θ1 and the inclined angle θ2; increasing θ1 or decreasing θ2 not only significantly improves the energy absorption capacity of the honeycomb but also facilitates the generation of a more pronounced double plateau region on the stress-strain curve; by changing the length of the crossed inclined wall, three improved CSSHs(ICSSH) can be obtained. Among them, by adjusting the length of the crossed inclined wall in the horizontal direction, the structure with the superior energy absorption capacity can be obtained. The structure with excellent deformation stability can be obtained through adjusting the length of the crossed inclined wall in the vertical direction. Results show that the performance of CSSH is better than that of SSH, with a specific energy absorption (SEA) of 245% higher than that of SSH. This work is expected to guide the design of new auxetic honeycombs with better energy absorption properties, and can also provide a reference for the optimization of honeycombs.

Cavity inclination effect on convection flow in a triangular geometry

AbstractIn this study, the water convection flow within a right‐angled, inclined, and isosceles triangle enclosure for various inclination angles was numerically analyzed using the lattice Boltzmann method with the multirelaxation time model. On the hypotenuse side, the enclosure is thermally insulated, while the left and horizontal walls are kept, respectively, at cold and hot temperatures. This study was conducted to show the effects of two key parameters, the tilt angle and the Rayleigh number , whose changes span from to and to , respectively. The effect of these variables is presented in terms of streamlines, isotherms, velocity profiles, temperature plots, and the average Nusselt number. Furthermore, the impact of the size of a hot square obstruction inside the cavity on the isotherms and streamlines has been investigated. The findings demonstrate that the rate of heat transport is enhanced as the Rayleigh number increases. This result is in good agreement with earlier research without tilting the cavity. Depending on the Rayleigh number, the tilt angle has a significant effect on the rate of heat transmission.

Simulation of combined convective-radiative heat transfer of hybrid nanofluid flow inside an open trapezoidal enclosure considering the magnetic force impacts

In this research, the combined convective-radiative heat transfer for magnetohydrodynamics (MHD) hybrid nanofluid flow inside an open trapezoidal enclosure are numerically simulated. There are two diagonal side walls and a horizontal wall defining this open enclosure. This enclosure's inclined side walls are accurately modeled using the embedded boundary approach. Calculations of thermal radiation term in the energy equation are done based on the Roseland approximation. The nanofluid applied in this research is a mixture of hybrid Al2O3-CuO nanoparticles and H2O base fluid. To investigate the thermal treatment, distributions of dimensionless temperature in the enclosure and the variations of Nusselt numbers on its bottom hot wall are presented for various magnitudes of radiative parameter, hybrid nanoparticles volume fractions and magnetic force. The obtained findings indicate the highest magnitude of total heat transfer rate on the enclosure bottom hot wall is registered in absence of magnetic force Ha=0 and for highest values of radiative parameter Rd=1 and hybrid nanoparticles concentration ϕ=0.03Al2O3+0.03CuO.

КАМ’ЯНІ ГРОБНИЦІ ЗРУБНОЇ КУЛЬТУРИ ПІВНІЧНОГО ПРИАЗОВ’Я (ЗА МАТЕРІАЛАМИ КОМИШУВАТСЬКОГО МОГИЛЬНИКА)

The article presents the results of research on the burials of the Late Bronze Age Zrubna/Timber-grave culture in the stone tombs of the barrow group near the village of Komyshuvate in the North Azov region in the south of Donetsk region of Ukraine. The article considers the ritual and inventory complex of burials through the prism of the created general register of burial mounds of the Zrubna/Timber-grave culture of the North Azov region. This allowed us to clarify and systematise the source base, to give a comprehensive formalised statistical description of the funerary sites, to consider some aspects of the social organisation, material and spiritual culture of the Late Bronze Age tribes based on the data of the studied necropolis. The article analyses the stone tombs of the North Azov region, which are divided into three main groups according to their design features. The distribution of funerary complexes made in different types of burial structures by horizons allowed us to clearly illustrate the previously identified chronological features that reflect the time of appearance of a particular type of grave. The Azov mounds are largely characterised by a variety of stone architecture. The area of distribution of burial mounds with stone structures is quite extensive. However, the use of stone in mound construction is unevenly distributed and is not typical for the whole region. The mapping method allowed us to identify the location of burials with stone structures in the immediate vicinity of the raw material base. These burial grounds tend to be located in the areas of the Donetsk Ridge and the Azov Upland, which are rich in open outcrops of natural stone. The Don Delta is the eastern border of the widespread use of stone in funerary rites. In the western part of the Donetsk Ridge, in the upper rivers of the Dnipro basin, the use of stone in mound construction was not practised. Large-scale stone structures in the mounds to the west of the Berda River also remain unknown. Stratigraphic observations and analysis of the ritual and inventory complex made it possible to establish with a certain degree of probability the sequence of construction of the mounds of the Komyshuvate burial ground and the burials made in them. Qualitative features manifested in the shape and proportions of ceramic vessels, material composition, surface treatment and ornamentation allowed us to attribute the ceramic corpus of the burials of the Komyshuvate cemetery to the second (developed) horizon of the Zrubna/Timber-grave culture cemeteries of the North Azov region. According to the proposed classification, tomb 1 of mound 1 of the Komyshuvate cemetery belongs to group I (tombs with vertical masonry walls), tomb 1 of mound 4 - to group II (tombs with horizontal masonry walls), and tomb 2 of mound 4 - to group III (combined tombs with horizontal and vertical masonry walls). Burial 2 of Mound 4 and burial 1 of Mound 1 can be confidently attributed to the second (developed) horizon of the Zrubna/Timber-grave culture of the North Azov region based on the ritual and inventory complex of features. The inlet stratigraphic position and the ritual and inventory complex of burial 1 of mound 4 allow us to attribute it to the final of the II (developed) or beginning of the III (late) horizon. The late horizon is characterised by inlet burials, less often by main burials in mounds, in ground pits under stone structures, as well as in classical tombs with horizontal masonry walls and combined stone tombs, which were most common in this period. In addition, the analysis of the materials allowed us to approach the problem of social reconstructions. Researchers have repeatedly pointed out that burials in stone tombs with horizontal and combined masonry walls are distinguished by their equipment and a set of ritual features as having a high social status. Thus, the construction in the form of a stone tomb is in itself extraordinary and a sign of social rank. Both burials of barrow 4 of the Komyshuvate cemetery demonstrate a number of deviations from the model of a regular burial of the Zrubna/Timber-grave culture of the North Azov region. The presence in the burial of a wooden bowl with a metal figured rim and a "ceremonial" ceramic vessel with a "calendar" motif are status signs marking the persons involved in ritual activities. The presence of traces of ritual actions outside the grave, a stone roof over a complex stone structure, excessive equipment and meat food (the honorary back part) are also clear indicators of the social extraordinariness of the deceased and signs of high rank. Keywords: North Azov region, archaeological research, Late Bronze Age, Zrubna/Timber-grave culture, barrow, tomb, stone architecture.

Internally heated convection of viscoplastic fluids in enclosures using a lattice Boltzmann method

Thermal convection driven by an internal heat source in a two-dimensional enclosure filled with viscoplastic fluids is investigated numerically. Two vertical side walls of the cavity are isotherms with the same low temperatures, while the horizontal walls are adiabatic and insulated. An exact Bingham model is applied in the constitutive equation for the viscoplastic fluid. A lattice Boltzmann method (LBM) is developed to solve the introduced non-dimensional macroscopic equations, and the derivations of the LBM are presented and discussed. The implemented LBM is validated against previous studies of internal natural convection. The effects of the Rayleigh–Roberts number, the Prandtl number, the aspect ratio of the cavity, and the inclined angle of the enclosure on the yielded/unyielded parts are investigated and reported. The maximum (or critical) Bingham (Bn) and yield (Y) numbers for the studied parameters are investigated through the defined Nusselt number. The results are depicted by the contours of isotherms, streamlines, yielded/unyielded zones, vorticity, and horizontal and vertical velocities. In addition, the temperatures and velocities in the middle of the cavity as well as the Nusselt number are shown and discussed. It was revealed that the maximum (or critical) yield number is independent of Rayleigh–Roberts and Prandtl numbers same as external natural convection. The values of the critical yield number decrease gradually as the inclined angle rises counterclockwise. However, the critical yield number enhances with the increase in the aspect ratio although the augmentation is not linear and steady.

A numerical study of the salt water flow inside a channel with horizontal metal walls subjected to a constant DC voltage realizes a uniform electrostatic field contributing to the desalination of seawater by forcing cations (Na+) and anions (Cl–) to deflect: effect of electrostatic field intensity and temperature variation

A numerical study of the salt water flow inside a channel with horizontal metal walls subjected to a constant DC voltage realizes a uniform electrostatic field contributing to the desalination of seawater by forcing cations (Na+) and anions (Cl–) to deflect: effect of electrostatic field intensity and temperature variation

Atypically Gastric Tumor with Unexpected Evolution: A Case Report

We present the case of a 62 year old male with no relevant medical history, who for the last two months had been complaining of dysphagia for solids and liquids, marked physical fatigue, oliguria. Clinical examination revealed palor and dehydrated skin, as well as a tumoral mass of 10/10 cm palpable in the upper abdomen. Upper digestive endoscopy was performed, showing a vegetant lesion of 6 cm on the gastric angle, with a central ulcer of 4 cm. The oesophagus and duodenum were normal, and Helicobacter pylori test was negative. Histological exam from the gastric lesion revealed diffuse large-cell malignant lymphoid tumoral proliferation, with tumoral cells infiltrating the mucosa between the glands. Immunohistochemical analysis diagnosed B cell lymphoma. CT scan of the thorax, abdomen and pelvis was performed, revealing multiple tumors involving the gastric walls, the posterior parietal peritoneum, the intra-peritoneal fat, the pancreatic tissues and the right antero-inferior mediastinum, as well as multiple adenopathies on both sides of the diaphragm and ascites. We performed paracentesis, and malignant cells were detected in the peritoneal fluid. Bone marrow biopsy was normal. The patient was referred to the hematology department for treatment. He received chemotherapy including CHOP followed by RICE with the disappearance of the gastric tumor on upper endoscopy and the disappearance of peritoneal, mediastinal and pancreatic region tumors with the persistence of a circumferential thickening of the horizontal gastric region walls on CT reevaluation.

DOUBLE-DIFFUSIVE CONVECTION-REACTION FLOW IN A SQUARE ENCLOSURE FILLED WITH POROUS MEDIUM

In this work, we analyze the double-diffusive convection-reaction of a binary mixture in a square enclosure filled with a porous media, with constant temperatures and concentrations at the two vertical walls and adiabatic and impermeable horizontal walls. The boundaries of the enclosure are under chemical equilibrium. The porous medium is assumed to be in local thermal equilibrium (LTE) state and the solubility of the dissolved salts depends on temperature. The two-dimensional steady-state flow rate is determined by a non-Darcy (Darcy-Brinkman) model, and the entire governing equations are solved using the usual SIMPLE-R finite-volume methodology. It has been found that as the reaction rate increases in the system the salt precipitation also increases, causing a decrease in overall mass transfer rate. Also, the chemical reaction tends to decrease the overall heat transfer-rate.