Squeezing Flow Research Articles

Yield stress of fine cement-based mortars: Challenges and potentials with rotational and compressional testing methods

The present study aims to evaluate the static yield stress of cement-based mortar mixtures using the parallel-plates geometry with rotational and compressional testing set-ups. In total, six mortar mixtures with various water-to-cement (W/C) and sand-to-cement (S/C) ratios, as well as high-range water reducer (HRWR) dosages were used for investigation. Two rotational methods namely the constant-shear rate (CSR) and the steady-shear, as well as the squeeze flow test were employed to assess the yield stress of the investigated mortar mixtures. For the latter, a stress-controlled uniaxial compression machine was developed allowing a high precision to monitor and control the compressional force and the deformation. The CSR test results indicated that a 7% increase in the W/C ratio and addition of 0.5% polycarboxylate ether-based HRWR led to around 20% and 50% reduction in the yield stress, respectively. Nevertheless, the effect of W/C ratio and the PCE-based HRWR was even more pronounced in the case for the steady-shear test. Both methods were highly prone to the wall-slip phenomenon reflected by considerably lower shear stress values obtained with the smooth rotating plate. However, when a rough rotating plate was employed, the CSR method led to around 65% (in average) higher static yield stress values compared to those obtained using the steady-shear test. The uniaxial compression test results were in good agreement with the rotational tests from a comparative point of view. However, it seems to exist a threshold of the material’s consistency beyond which the compressional test set-up results are more reliable. Accordingly, mixtures with a minimum CSR static yield stress of 345 Pa were found to be adapted for testing using this set-up. The adoption of the testing methods proposed in this study led to obtaining different value ranges for the yield stress of the mortars which indicated the ability of each test to capture different transitions reflecting microscopic and macroscopic changes.

Squeeze flow in multilayer polymeric films: Effect of material characteristics and process conditions

AbstractIn this work, effects of sealing temperature, time, pressure, as well as sealant thickness and viscosity on squeeze out flow (SOF) in heat sealing were examined. A new image analysis approach is presented to quantify SOF in heat sealing. It was found that increasing temperature or pressure could improve SOF but only in thick 130 μm sealants and reducing the sealant thickness to 50 μm suppressed SOF. Reducing viscosity in 50 μm sealant films was also found to improve SOF only at high‐sealing pressure and long sealing times. Three approaches were used to model SOF: analytical one‐dimensional model, numerical one‐dimensional model using finite difference method (FDM), (iii) Numerical two‐dimensional model using finite element analysis. Heat transfer was modeled, and it was shown that heat transfer induces a delay in SOF. When the FDM and the heat transfer models were combined, a good agreement between experimental and model prediction could be obtained. In addition, modeling results showed that SOF occurred in shear rates within the transition region between the Newtonian and Power‐law regions. This indicates the importance of considering the Carreau‐Yasuda fluid behavior in modeling of SOF.

Predicting thickness perception of liquid food products from their non-Newtonian rheology

The “mouthfeel” of food products is a key factor in our perception of food quality and in our appreciation of food products. Extensive research has been performed on what determines mouthfeel, and how it can be linked to laboratory measurements and eventually predicted. This was mainly done on the basis of simple models that do not accurately take the rheology of the food products into account. Here, we show that the subjectively perceived “thickness” of liquid foods, or the force needed to make the sample flow or deform in the mouth, can be directly related to their non-Newtonian rheology. Measuring the shear-thinning rheology and modeling the squeeze flow between the tongue and the palate in the oral cavity allows to predict how a panel perceives soup “thickness”. This is done for various liquid bouillons with viscosities ranging from that of water to low-viscous soups and for high-viscous xanthan gum solutions. Our findings show that our tongues, just like our eyes and ears, are logarithmic measuring instruments in agreement with the Weber-Fechner law that predicts a logarithmic relation between stimulus amplitude and perceived strength. Our results pave the way for more accurate prediction of mouthfeel characteristics of liquid food products.

Three-dimensional unsteady squeezing flow with irreversibility

Three-dimensional unsteady squeezing flow with irreversibility

Role of resin percolation in gap filling mechanisms during the thin ply thermosetting automated tape placement process

During the automated tape placement process, gaps between adjacent tapes are created due to the limitation of machine accuracy, especially at higher speeds. These gaps are undesirable as they cause porosity, thickness variation, and fiber waviness, introducing defects in the composite part. Applying pressure and temperature to part can assist in partially or completely filling these gaps. For thermosetting resins, such processing is usually required for the material to reach complete consolidation. Modeling the tape deformation as squeeze flow of fibrous suspension in the liquid matrix is usually deployed to determine gap filling and tape deformation. However, existence of resin rich zones in the micrographs of fabricated parts suggests that there may be a second flow process involved which is the percolation of matrix through the fiber bed into the remaining empty space of the gaps. This paper extends the previous work that modeled the cross-ply deformation and squeeze flow as the primary mechanisms in the gap filling process during consolidation of thermosetting composites. Based on our experimental results, this work adds the percolation flow to the model to predict (1) the spread of fiber/matrix suspension into the gap, (2) the resin percolation out of the fiber bed into the gap and (3) the deformation of the cross (bridging) ply or plies. The governing equations are formulated, and scaling analysis is performed to estimate the effect of tape thickness on percolation flow confirming that this mechanism is more significant when thin tapes are employed. Fixed mesh numerical scheme is used to evaluate the deformation and flow progression of both the resin percolation flow and the squeeze flow of fiber/resin suspension during the consolidation process. A parametric study is conducted to evaluate the effect of model parameters. Finally, the predicted percolated resin flow along with squeeze flow advancement is compared with experimental results.

Evaluation of rheological properties of mortar with TiO2 addition

Abstract Adding TiO2 tocoating mortars is carried out to promote self-cleaning through photocatalytic activity. However, this addition influences the workability of the mortar and, consequently, the application stage as the TiO2 used can present a large number of fine particles and a high surface area, increasing the demand for mixing water, requiring consistency adjustments before coating. In this work, three mortars (two with the addition of different types of TiO2 and one reference) were developed on a laboratory scale to maintain similar workability, using the flow table test. The amount of kneading water was changed to maintain a spread of 220 ± 10 mm and the content of air-entrained was kept constant, around 25%. The mortars were evaluated using the squeeze flow method. Then, a blind test was performed to assess the mason sensitivity during handling and application of the coating, and all mortars were considered similar. However, the yield of the compositions with TiO2 addition was lower compared to the reference composition, making it possible to explain the results based on the physical parameters of the formulations and with a more in-depth analysis of the rheological indices obtained by the squeeze flow test.

Intelligent computing technique based supervised learning for squeezing flow model

In this study, the unsteady squeezing flow between circular parallel plates (USF-CPP) is investigated through the intelligent computing paradigm of Levenberg–Marquard backpropagation neural networks (LMBNN). Similarity transformation introduces the fluidic system of the governing partial differential equations into nonlinear ordinary differential equations. A dataset is generated based on squeezing fluid flow system USF-CPP for the LMBNN through the Runge–Kutta method by the suitable variations of Reynolds number and volume flow rate. To attain approximation solutions for USF-CPP to different scenarios and cases of LMBNN, the operations of training, testing, and validation are prepared and then the outcomes are compared with the reference data set to ensure the suggested model’s accuracy. The output of LMBNN is discussed by the mean square error, dynamics of state transition, analysis of error histograms, and regression illustrations.

Influence of Thermophysical Features on MHD Squeezed Flow of Dissipative Casson Fluid with Chemical and Radiative Effects

Theoretical investigation of variable mass diffusivity, thermal conductivity, and viscosity on unsteady squeezed flow of dissipative Casson fluid is presented. Physically, for any effective heat and mass transfer process, a proper account of thermophysical properties in such a system is required to attain the desired production output. The magnetized free convective flow of unsteady Casson fluid encompassing Joule dissipation, radiation, and chemical reactive influence is induced as a result of squeezing property. The governing model assisting the magnetized flow is formulated and transformed via an appropriate similarity transformation. The resulting set of ordinary differential equations is solved numerically using Chebyshev based Collocation Approach (CCA). However, variable viscosity, thermal conductivity, and mass diffusivity effects are seen to diminish the fluid flow velocities, temperature, and concentration respectively along with the lower plate. Heat and mass transfer coefficient, skin friction downsized to an increasing value of variable thermal and mass diffusivity parameters while variable viscosity pronounces the skin friction coefficient. Furthermore, the present analysis is applicable in polymer processing, such as injection molding, extrusion, thermoforming among others.

A Levenberg-Marquardt backpropagation method for unsteady squeezing flow of heat and mass transfer behaviour between parallel plates

In this study, a new computing model by developing the strength of feed-forward neural networks with Levenberg-Marquardt Method (NN-BLMM) based backpropagation is used to find the solution of nonlinear system obtained from the governing equations of unsteady squeezing flow of Heat and Mass transfer behaviour between parallel plates. The governing partial differential equations (PDEs) for unsteady squeezing flow of Heat and Mass transfer of viscous fluid are converting into ordinary differential equations (ODEs) with the help of a similarity transformation. A dataset for the proposed NN-BLMM is generated for different scenarios of the proposed model by variation of various embedding parameters squeeze Sq, Prandtl number Pr, Eckert number Ec, Schmidt number Sc and chemical-reaction-parameter [Formula: see text]. Physical interpretation to various embedding parameters is assigned through graphs for squeeze Sq, Prandtl Pr, Eckert Ec, Schmidt Sc and chemical-reaction-parameter [Formula: see text]. The processing of NN-BLMM training (T.R), Testing (T.S) and validation (V.L) is employed for various scenarios to compare the solutions with the reference results. For the fluidic system convergence analysis based on mean square error (MSE), error histogram (E.H) and regression (R.G) plots is considered for the proposed computing infrastructures performance in term of NN-BLMM. The results based on proposed and reference results match in term of convergence up to 10-02 to 10-08 proves the validity of NN-BLMS. The Optimal Homotopy Asymptotic Method (OHAM) is also used for comparison and to validate the results of NN-BLMM.

Dufour and Soret Effect on Viscous Fluid Flow between Squeezing Plates under the Influence of Variable Magnetic Field

The aim of this article is to investigate the effect of mass and heat transfer on unsteady squeeze flow of viscous fluid under the influence of variable magnetic field. The flow is observed in a rotating channel. The unsteady equations of mass and momentum conservation are coupled with the variable magnetic field and energy equations. By using some appropriate similarity transformations, the partial differential equations obtained are then converted into a system of ordinary differential equations and are solved by Homotopy Analysis Method (HAM). The influence of the natural parameters are investigated for the velocity field components, magnetic field components, heat and mass transfer. A direct effect of the squeeze Reynold number is observed on both concentration and temperature. Moreover, increasing the magnetic Reynold number shows an increase in the fluid temperature, but in the case of concentration, an inverse relation is observed. Furthermore, a decreasing effect of the Dufour number is observed on both concentration and temperature distribution. Besides, in case of the Soret number, a direct effect is observed on concentration, but an inverse effect can be seen on temperature distribution. Different effects are shown through graphs in this study and an error analysis is also presented through tables and graphs.

Effect of sugar addition on the elongational and shearing deformation behavior of sesame paste systems

The structural characteristics of series of mixtures of sesame paste with different sugars were studied using various rheological techniques. The sugars employed were sucrose and fructose in powder form; maltose and isoglucose in the form of corn syrup. The sesame paste was prepared either from unroasted or roasted sesame seeds. The rheological measurements were carried out using uniaxial compression to determine the Young's modulus of elasticity, lubricated squeeze flow viscometry to determine elongational viscosity as well as dynamic and creep small deformation tests. Roasted or unroasted sesame paste exhibited higher values of Young's modulus comparing to the sesame paste-sugar systems. Significant differences were recorded in the elongational viscosity values of the resulting sesame paste-sugar mixtures. The behavior of a concentrated fluid was observed for all systems. The viscosity of the sesame paste-sugar systems was affected by the concentration of sugar in the mixture and the temperature of measurement as well. Overall, results indicated that the structure of the sesame paste-sugar systems examined was mainly affected by the ratio of the sesame paste to sugar content present in each mixture.

Flow Dynamics of the Homogeneous and Heterogeneous Reactions with an Internal Heat Generation and Thermal Radiation between Two Squeezing Plates

This paper explores the time dependent squeezing flow of a viscous fluid between parallel plates with internal heat generation and homogeneous/heterogeneous reactions. The motive of the present effort is to upgrade the heat transformation rate for engineering and industrial purpose with the rate of chemical reaction. For this purpose the equations for the conservation of mass, momentum, energy and homogeneous/heterogeneous reactions are transformed to a system of coupled equations using the similarity transformation. According to HAM, with the proper starting assumptions and other factors, a similarity solution may be found. On the way to verifying the validity and correctness of HAM findings, we compare the HAM solution with numerical solver programme BVP4c to see whether it matches up. The results of a parametric inquiry are summarized and presented with the use of graphs.

Exploration of Unsteady Squeezing Flow through Least Squares Homotopy Perturbation Method

Squeezing flow has many applications in different fields including chemical, mechanical, and electrical engineering as these flows can be observed in many hydrodynamical tools and machines. Due to importance of squeezing flow, in this paper, an unsteady squeezing flow of a viscous magnetohydrodynamic (MHD) fluid which is passing through porous medium has been modeled and analyzed with and without slip effects at the boundaries. The least squares homotopy perturbation method (LSHPM) has been proposed to determine the solutions of nonlinear boundary value problems. To check the validity and convergence of the proposed scheme (LSHPM), the modeled problems are also solved with the Fehlberg–Runge–Kutta method (RKF45) and homotopy perturbation method (HPM) and residual errors are compared with LSHPM. To the best of the authors’ knowledge, the current problems have not been attempted before with LSHPM. Moreover, the impact of different fluid parameters on the velocity profile has been examined graphically in slip and no-slip cases. Analysis shows that the Reynolds number, MHD parameter, and porosity parameter have opposite effects in case of slip and no slip at the boundaries. It is also observed that nonzero slip parameter accelerates the velocity profile near the boundaries. Analysis also reveals that LSHPM provides better results in terms of accuracy as compared to HPM and RKF45 and can be effectively used for the fluid flow problems.

Falkner–Skan Equation with Heat Transfer: A New Stochastic Numerical Approach

In this study, a new computing model is developed using the strength of feedforward neural networks with the Levenberg–Marquardt method- (NN-BLMM-) based backpropagation technique. It is used to find a solution for the nonlinear system obtained from the governing equations of Falkner–Skan with heat transfer (FSE-HT). Moreover, the partial differential equations (PDEs) for the unsteady squeezing flow of heat and mass transfer of the viscous fluid are converted into ordinary differential equations (ODEs) with the help of similarity transformation. A dataset for the proposed NN-BLMM-based model is generated in different scenarios by a variation of various embedding parameters, Deborah number ( β ) and Prandtl number (Pr). The training (TR), testing (TS), and validation (VD) of the NN-BLMM model are evaluated in the generated scenarios to compare the obtained results with the reference results. For the fluidic system convergence analysis, a number of metrics such as the mean square error (MSE), error histogram (EH), and regression (RG) plots are utilized for measuring the effectiveness and performance of the NN-BLMM infrastructure model. The experiments showed that comparisons between the results of the proposed model and the reference results match in terms of convergence up to E-05 to E-10. This proves the validity of the NN-BLMM model. Furthermore, the results demonstrated that there is an increase in the velocity profile and a decrease in the thickness of the thermal boundary layer by increasing the Deborah number. Also, the thickness of the thermal boundary layer is decreased by increasing the Prandtl number.

Hall currents effect on squeezing flow of non-Newtonian nanofluid through a porous medium between two parallel plates

An analysis is carried out to study the problem of unsteady squeezing flow of a non-Newtonian nanofluid through a porous medium between two parallel plates. The effects of Hall currents and heat source are taken into consideration. The governing partial differential equations are transformed into a set of nonlinear ordinary differential equations by using similarity transformations. A homotopy perturbation method is performed to obtain analytical solutions for that system of equations. The behaviors of the tangential velocity, normal velocity, temperature, and nanoparticles concentrations distributions are discussed analytically and graphically under the effect of different entering parameters. Physically, our model corresponds to squeezing problems in tunnelling such as study the relation between rock types and its depths in squeezing cases and time dependent stress induced problem in sandstone. This problem provides interesting results which may have many applications in chemistry, biology, and medicine.

An optimal variational iteration method for investigating the physical behavior of quasi-steady squeezing flow confined between parallel rigid walls

An efficient numerical method for investigating the physical behavior of an axisymmetric 2D incompressible squeeze flow between two rigid parallel plates is proposed. Due to the low velocity of the moving rigid wall, the flow is considered as a quasi-steady flow. The nonlinear governing equations can be transformed to a single fourth-order nonlinear differential equation. A new efficient iteration method based on coupling of variational iteration method with some auxiliary convergence-control parameters, known as the optimal variational iteration method is proposed to obtain a solution for the generated nonlinear fourth-order differential equation. In the proposed method, the residual function and its error of norm two are implemented to change the problem into an optimization one in order to choose the auxiliary convergence-control parameters optimally. Consequently, a good approximate solution is obtained. The main benefit of the proposed method is the availability of adjusting and controlling the convergence region in an easy way. This property leads to faster convergence, simplicity of wide-range application and efficiency. To show the efficiency and accuracy of the established method, the problem is also solved by various iterative methods, such as perturbation method, homotopy perturbation method and optimal homotopy asymptotic method. As a comparison, the proposed method provides a straightforward way to control the convergence and consequently readily tuning the convergence regions. These properties lead to quick convergence to the exact solution and needing less computational efforts.

Rheological behavior and flow induced microstructural changes of cement-based mortars assessed by Pressure Mapped Squeeze Flow

Squeeze flow is used for rheological evaluation of many classes of materials. It can be performed in different configurations and is particularly interesting for heterogeneous materials that go through similar conditions during practical application. The assessment of pressure distribution during the test can provide additional information about flow conditions. For that reason, Pressure Mapped Squeeze Flow (PMSF) has been previously presented and is employed in this work with constant volume configuration for the first time. Cement-based mortars were examined, four formulated in laboratory with differences regarding the presence or not of cellulose ether admixture and hydrated lime, and one factory-produced mortar. Bulk squeeze flow results are analyzed in parallel with raw pressure distribution images. The evolution of the area as measured by the sensor is contrasted with the constant volume hypothesis. Pressure distribution calibrated results are compared to predictions from theoretical models. Flow induced microstructural changes indicated by the obtained results are explained based on the concept of interparticle spacing. The method can be useful for the rheological analysis of heterogeneous materials under partially confined flow.

Unsteady squeezing flow of a magnetized nano-lubricant between parallel disks with Robin boundary conditions

The aim of the present work is to examine the impact of magnetized nanoparticles (NPs) in enhancement of heat transport in a tribological system subjected to convective type heating (Robin) boundary conditions. The regime examined comprises the squeezing transition of a magnetic (smart) Newtonian nano-lubricant between two analogous disks under an axial magnetism. The lower disk is permeable whereas the upper disk is solid. The mechanisms of haphazard motion of NPs and thermophoresis are simulated. The non-dimensional problem is solved numerically using a finite difference method in the MATLAB bvp4c solver based on Lobotto quadrature, to scrutinize the significance of thermophoresis parameter, squeezing number, Hartmann number, Prandtl number, and Brownian motion parameter on velocity, temperature, nanoparticle concentration, Nusselt number, factor of friction, and Sherwood number distributions. The obtained results for the friction factor are validated against previously published results. It is found that friction factor at the disk increases with intensity in applied magnetic field. The haphazard (Brownian) motion of nanoparticles causes an enhancement in thermal field. Suction and injection are found to induce different effects on transport characteristics depending on the specification of equal or unequal Biot numbers at the disks. The main quantitative outcome is that, unequal Biot numbers produce significant cooling of the regime for both cases of disk suction or injection, indicating that Robin boundary conditions yield substantial deviation from conventional thermal boundary conditions. Higher thermophoretic parameter also elevates temperatures in the regime. The nanoparticles concentration at the disk is boosted with higher values of Brownian motion parameter. The response of temperature is similar in both suction and injection cases; however, this tendency is quite opposite for nanoparticle concentrations. In the core zone, the resistive magnetic body force dominates and this manifests in a significant reduction in velocity, that is damping. The heat build-up in squeeze films (which can lead to corrosion and degradation of surfaces) can be successfully removed with magnetic nanoparticles leading to prolonged serviceability of lubrication systems and the need for less maintenance.

Heat and mass transfer in an unsteady squeezed Casson fluid flow with novel thermophysical properties: Analytical and numerical solution

AbstractThis study investigates the heat and mass transfer in an unsteady squeezing flow between parallel plates under the influence of novel variable diffusivity. In most of the literature, it is believed that the thermophysical properties of the fluid are unchanged. However, this present study bridges this gap by assuming that viscosity, conductivity, and diffusivity are all temperature‐dependent. Physically, an appropriate analysis of thermophysical variables in such a system is required to achieve the best performance for effective heat and mass transfer processes. The equations controlled were first nondimensional and then simplified by a similarity transformation to ordinary nonlinear differential equations. The present study provides a fast convergent method on finite parallel plates, namely, the optimal homotopy analysis method (OHAM) and spectral collocation method (SCM) are used to analyze the fluid flow, heat, and mass transport. The graphical and table understanding is given via an error table and flow behavior of physical parameters. The result reveals that the SCM is more accurate than OHAM. However, the method employed in this paper offers excellent convergence solutions with good accuracy. The solution convergence is also discussed. In this type of problem, squeeze numbers play an important role and the rise in the squeezing parameter increases the fluid temperature.

Unsteady squeezing flow of Cu-Al2O3/water hybrid nanofluid in a horizontal channel with magnetic field

The proficiency of hybrid nanofluid from Cu-Al2O3/water formation as the heat transfer coolant is numerically analyzed using the powerful and user-friendly interface bvp4c in the Matlab software. For that purpose, the Cu-Al2O3/water nanofluid flow between two parallel plates is examined where the lower plate can be deformed while the upper plate moves towards/away from the lower plate. Other considerable factors are the wall mass suction/injection and the magnetic field that applied on the lower plate. The reduced ordinary (similarity) differential equations are solved using the bvp4c application. The validation of this novel model is conducted by comparing a few of numerical values for the reduced case of viscous fluid. The results imply the potency of this heat transfer fluid which can enhance the heat transfer performance for both upper and lower plates approximately by 7.10% and 4.11%, respectively. An increase of squeezing parameter deteriorates the heat transfer coefficient by 4.28% (upper) and 5.35% (lower), accordingly. The rise of suction strength inflates the heat transfer at the lower plate while the presence of the magnetic field shows a reverse result.