Effects Of Relevant Parameters Research Articles

An Accurate Calculation Method on Blasingame Production Decline Model of Horizontal Well with Dumbbell-like Hydraulic Fracture in Tight Gas Reservoirs

Blasingame production decline is an effective method to obtain permeability and single-well controlled reserves. The accurate Blasingame production decline curve needs an accurate wellbore pressure approximate solution of the real-time domain. Therefore, the aim of this study is to present a simple and accurate wellbore pressure approximate solution and Blasingame production decline curves calculation method of a multi-stage fractured horizontal well (MFHW) with complex fractures. A semi-analytical model of MFHWs in circle-closed reservoirs is presented. The wellbore pressure and dimensionless pseudo-steady productivity index JDpss (1/bDpss) are verified with a numerical solution. The comparison result reaches a good match. Wellbore pressure and Blasingame production decline curves are used to analyze parameter sensitivity. Results show that when the crossflow from matrix to natural fracture appears after the pseudo-state flow regime, the value of the inter-porosity coefficient has an obvious influence on the pressure approximate solution of the pseudo-steady flow regime in naturally fractured gas reservoirs. The effects of relevant parameters on wellbore pressure and the Blasingame decline curve are also analyzed. The method of pseudo-steady productivity index JDpss can applied to all well and reservoir models.

Legendre–Ritz solutions for vibration characteristics of three-dimensional double-layer lattice truss sandwich plates

In this paper, Legendre–Ritz solutions for vibration characteristics of double-layer lattice truss sandwich plates are proposed based on three-dimensional (3-D) elasticity theory. Double-layer lattice truss sandwich plates consist of three face sheets and two cores. The face sheets are composed of fiber-reinforced composites and the cores are composed of pyramidal lattice trusses made of isotropic materials. The pyramidal lattice core is equated to a homogeneous plate according to equivalence principle. Based on 3-D elasticity theory and pseudo excitation method (PEM), each layer's energy expressions of double-layer lattice truss sandwich plates are constructed. After that, Legendre polynomials are adopted to describe displacement components in length, width and thickness directions. On this basis, the Rayleigh-Ritz method is used to solve energy functions to obtain motion equations of double-layer lattice truss sandwich plates. The accuracy and validity of the present method are corroborated by comparisons with references and finite element method (FEM). Additionally, in order to find out effects of relevant parameters on dynamical characteristics of double-layer lattice truss sandwich plates, parametric studies are carried out by means of some numerical examples.

Stratification characteristics of hydrogen-blended natural gas for gas risers inside residential users

ABSTRACT In this paper, a CFD model is developed to examine the stratification characteristics of hydrogen-blended natural gas in residential gas risers. Meanwhile, the accuracy of the CFD model is validated by field experiments. The effects of relevant parameters on stratification are analyzed, including hydrogen blending ratio, riser internal diameter, riser height, media temperature, and media pressure. The relative importance of relevant parameters for stratification is identified using the orthogonal experiment design and improved grey relational analysis. Furthermore, a device is designed to mitigate the impact of blended gas stratification. The results show that the stratification of hydrogen-blended natural gas inside residential gas risers is significant in the direction of gravity. The maximum stratification height in standing for 8 h can reach up to 17.4 cm. The stratification height presents a negative correlation with riser internal diameter, riser height, and media temperature, while that represents a positive correlation with hydrogen blending ratio and media pressure. Furthermore, the effects of these parameters on stratification height could be ranked as follows: media pressure > hydrogen blending ratio > riser internal diameter > riser height > media temperature. These achievements provide effective guidance for residential users on safely using hydrogen-blended natural gas.

Research on Wear Behavior Between Crossed Parabolic Cylinders in the Early Stage of Cyclic Fretting

Abstract In practice, even the tiny relative reciprocating motion generated by external load or environmental vibration can cause interface wear. In this work, three-dimensional (3D) finite element analysis (FEA) is used to investigate the fretting wear between deformable crossed parabolic cylinders. Fretting is achieved by the application of a periodic displacement-controlled load, while the contact pair is defined as the same material, i.e., Carbon Steel/Carbon Steel, Copper Alloy/Copper Alloy, and Aluminum Alloy/Aluminum Alloy. Meanwhile, three different axis crossing angles are also studied, i.e., 45°, 60°, and 90°. Originally, a wide range of coefficients of friction (COFs) are applied to the interface without considering the damage. The results show that, when the COF is sufficiently large (µ = 1), the junction growth and the tangential load increase significantly in the first loading cycle, but then become gradually stable. Subsequently, the Archard wear model is applied to the frictional interface. Empirical equations for the initial gross slip distance and the wear volume at the end of the partial slip are established in turn. Furthermore, an empirical equation for the wear volume of a single fretting cycle is established, which is in good agreement with the FEA results. Lastly, the effect of relevant parameters on the wear volume for a single fretting cycle under elastic condition is discussed, but also the evolution of wear volume in the early stage of cyclic fretting. All the results are normalized, enabling their application to the 3D fretting wear of other material pairs.

Research and Validation of CF/PEEK-Based Truss Rod Crimping and Pultruding Process for On-Orbit Isoform Forming.

A crimping and pultruding forming process for truss rods using Carbon Fiber (CF)/Polyether-Ether-Ketone (PEEK) prepreg tape as the raw material is proposed to address the problem of continuous manufacturing of space trusses on orbit. The proposed process provides material rods for continuous truss manufacturing. Through numerical simulation and experimental verification, the effects of relevant parameters on the forming process are determined, an efficient method of rod curl pultrusion, in-rail, equal material forming is proposed, and the structural configuration of the rod curl pultrusion forming mold is determined. The equivalent macroscopic mechanical properties of unidirectional CF/PEEK prepreg strips are considered, and the rod-forming process is investigated. Rod samples with different process parameters are prepared, and several tests are conducted on them. The results show that the forming load pull is negatively correlated with the temperature at the same forming speed, and forming speed is positively correlated with the forming load pull at a certain temperature. Temperature and speed affect the surface quality of the rod, the density of the material filling, and the mechanical properties of the rod. The optimal forming process parameters are determined through numerical simulation and experimental verification. The developed molding technology has the advantages of high efficiency, low energy consumption, and high integration. It reduces manufacturing costs and improves manufacturing efficiency, so it can serve as a new and effective solution for the manufacturing of high-performance truss rods in the aerospace field.

Numerical Investigation of Air-Steam Condensation in a Vertically Enhanced Tube with Concave and Convex Surfaces

Condensation heat transfer enhancement technology is an important problem for heat exchangers. The air-steam condensation inside a vertically enhanced tube with concave and convex surfaces is analyzed numerically, and the effects of relevant parameters on thermohydraulic performance are discussed. The numerical results show that the drop in steam and temperature between the inlet and outlet is improved by 53.8% and 96.8%, respectively, compared with smooth tubes. In the condensation process, the noncondensable gas accumulates near the wall, which leads to the deterioration of condensation. The structures of concave and convex surfaces disrupt the boundary layer flow and noncondensable gas film and promote flow mixing, leading to enhanced condensation heat transfer. All the numerical results provide guidance values for heat transfer enhancement technology in the applications of condensers.

A study on the influencing parameters in developing construction and demolition waste-based geopolymer concretes and their sustainability assessment

Construction and demolition waste (CDW) has been recently identified as a potential aluminosilicate source for geopolymers. However, the available research has mainly focused on developing CDW-based geopolymer pastes and mortars, while studies on geopolymer concretes sourced from CDW have been very limited. Thus, the current study aimed at experimentally identifying different CDW materials suitable for producing geopolymer concretes. Additionally, the study analysed the mechanical, microstructural, and environmental properties of CDW- based geopolymer concrete produced. In this regard, the effect of relevant parameters on the compressive strength development of CDW-based geopolymer concretes was comprehensively investigated, including those related to precursor types/fineness, alkali activator solution, aggregate type/size and curing regimes. Microstructural analyses were also conducted on the selected samples (100% brick waste, 100% tile waste, 100% concrete waste and 75% brick waste + 25% GGBS). Finally, the environmental impact of geopolymer concrete was assessed and compared with similar traditional concrete. Results showed that employing CDWs alone is not suitable to achieve sufficient strengths under all curing regimes. However, the inclusion of 25% GGBS significantly improved the strength performance of CDW-based geopolymer concrete, in comparison to other supplementary cementitious materials (SCMs) such as Class-C fly ash and calcium hydroxide. The particle size of CDWs and concentration of alkaline activators highly affect the performance of CDW-based geopolymer concretes. Utilization of CDWs with particles finer than 75 μm and high concentrations of NaOH (12 M) is recommended to achieve good performance. The results also indicate that almost similar energy is needed for producing CDW-based geopolymer and OPC-based traditional concrete, whereas a huge reduction in CO2 emission (∼40%) was estimated in the case of geopolymers. The outcomes of the current study are expected to contribute to the advancement of geopolymer concrete derived from CDW in addition to providing valuable insights into this type of concrete for practitioners and academics.

Exploration of double diffusive convection phenomena of viscous nanofluid with consideration of solar radiative flux and MHD impact through the peristaltic channel

The concerning article scrutinized the incompressible Casson fluid flow through the peristaltic path under the influence of MHD and double-diffusive convection with the association of variable conductivity, viscosity and radiative flux. Buongiorno’s model is applied to keenly observe the features of nanoparticles. To allegorize the consequences of a chemical reaction the “Arrhenius law” is manipulated. The differential equations of momentum, heat, chemical reaction and double diffusivity are solved numerically by manipulating the convenient transformation. We employ the MATLAB bvp4c approach to draw the graphs for generalized equations and the effects of relevant parameters on the flow characteristics are examined. Our research work exhibits the impact of solutal, thermal and nanoparticle Grashof numbers on the velocity profile. The Lewis number and activation energy manifest the opposite behavior for the rate of the chemical reaction. The temperature gradient declines in the pumping segment while rising up during the pumping less region by varying the Brownian and thermophoresis diffusion parameters. The results show that temperature diminish with the magnification in because the Prandtl number governs the relative thickness of the thermal and momentum boundary layers. The maximal region of the peristaltic flow’s diffusive convection grows as the Lewis number rises. Moreover, the effect of a magnetic field is elaborated with the aid of describing the graph that the presence of a magnetic field dwindles the velocity of fluid.

Theoretical analysis of shape factor of gas hydrate sediments under stress dependence

The Kozeny-Carman (KC) equation is used extensively to characterize the effective permeability of gas hydrate sediments. However, most existing modeling approaches ignore the changes in the effective stress, hydrate saturation, and pore structures of porous media, which significantly affect the extraction and exploration of gas hydrates. In addition, theoretical models that can accurately describe shape factors during the imbibition process and predict the effective permeability of gas hydrate sediments are rarely reported. This paper proposes a theoretical stress-dependent shape factor model to study the physical relations between the shape factor and relevant parameters (e.g., effective stress, hydrate saturation, effective porosity, and pore fractal dimension). Then, the derived model is extended to study the shape factor during the imbibition process. The two main novel features of the proposed model are: (1) it takes the effective stress, hydrate saturation, and pore structures into account; and (2) it can be used to study the evolution of shape factors during the imbibition process in gas hydrate sediments. The predictions from the developed model provide a good agreement with experimental results, which validates the model. In addition, based on the derived model, the effects of relevant parameters on shape factors are studied theoretically. From a practical standpoint, the model can not only estimate the effective permeability of gas hydrate sediments under stress dependence but also provide insight into the evolution of shape factor, pore structures (e.g., capillary total number, pore fractal dimension, tortuosity fractal dimension, and effective porosity) and hydrate pore habits during the extraction of hydrates.

Electrokinetic peristaltic transport of Bingham‐Papanastasiou fluid via porous media

AbstractAn important rheological mathematical model is created to investigate the rheological impacts of slip velocity and varied zeta potentials in an inclined asymmetric channel. The flow is taken in an isotropic porous medium and is governed by Bingham‐Papanastasiou model. The membrane based pumping analysis is done in a wave frame of reference moving with the speed of the wave. Flow model is simplified by considering small wave number δ, small Reynolds number and small Peclet number . The emerging linearized non‐dimensional system of equations is evaluated for analytical and numerical methods. The effects of sundry parameters on pumping, temperature θ, axial velocity u and trapping have been studied graphically. The viscous model is retrieved for Bingham number , or stress growth parameter . Finally, the effects of relevant parameters on heat transfer rate and shear stress at walls are discussed numerically. The results show that more pressure is required to flow same amount of fluid in an inclined channel. The temperature field θ is boosted by both the Bingham number and the continuation parameter M. It is also observed that different zeta potentials and velocity slip conditions are significant phenomena to influence channel flow. A pumping‐based device can be built using the existing model to combine and filter physiological samples and chemicals as well as to visualize the transit of physiological fluids.

Analysis of pulse electromagnetic electroosmotic flow of Jeffrey fluid through parallel plate microchannels under a constant pressure gradient

The purpose of this work is to investigate the pulse electromagnetic electroosmotic flow (EOF) behavior of a Jeffrey fluid in parallel plate microchannels under a constant pressure gradient. Analytical solutions for the velocity and volumetric flow rate are derived by employing the Laplace transform method and the residue theorem. In particular, the electric double layer (EDL) effect is considered, and an analysis is conducted on both the near-center and near-wall velocities. The flow periodicity is also noted, and these velocities are evaluated during the first and second half-cycles, respectively. Moreover, both 3D and 2D graphics are simultaneously utilized to visualize the impact of relevant parameters on velocity and volumetric flow rate. Our analysis yielded the following key findings: The effects of relevant parameters, such as pulse width a¯, pressure gradient Ω, Hartmann number Ha, electric field strength β, electrokinetic width K, relaxation time λ¯1 and retardation time λ¯2, on the near-center velocity during the first half-cycle align with the results of previous studies. During the second half-cycle, higher values of variables Ha and β lead to reduced velocities. Interestingly, during any half-cycle, the near-wall velocity demonstrates similar characteristics to the near-center velocity in response to variations in certain parameters, including Hartmann number Ha, electric field strength β, relaxation time λ¯1 and retardation time λ¯2. It is worth mentioning that the influence of relaxation time λ¯1 and retardation time λ¯2 on the near-wall velocity is largely independent of the Hartmann number, especially for the retardation time. Regardless of the values of the parameters λ¯1 and λ¯2, a higher volumetric flow rate is observed with an increased electrokinetic width K. Additionally, the volumetric flow rate profile of the Jeffrey fluid exhibits a comparatively smoother trend over time compared to that of the Maxwell fluid. The remarkable similarity between Jeffrey fluid and blood suggests that the results presented in this paper hold immense potential as a crucial reference for studying blood transport within the field of microfluidics.

Theoretical analysis of threshold pressure in tight porous media under stress

The threshold pressure is critical to characterizing multi-phase nonlinear flow through tight porous media under effective stress. Due to the complex and heterogeneous pore structures, the essential controls on the threshold pressure of tight porous media are not determined. In this study, based on the fractal theory, a theoretical model for the threshold pressure of gas–water two-phase flow through tight porous media is proposed. The derived model considers the effective stress, pore structures, gas–water capillary pressure, and boundary layer. The predicted threshold pressure from the developed model is in good agreement with the available experimental results, which validates the model. Moreover, based on the derived model, the effects of relevant parameters (e.g., gas–water surface tension, contact angle, initial porosity, and elastic modulus) on the threshold pressure are studied. Under a given effective stress, threshold pressure decreases as the initial porosity (or elastic modulus) increases. However, threshold pressure increases with the increase in gas–water surface tension (or contact angle). In addition, a positive relationship exists between threshold pressure and water saturation in tight porous media. From a practical standpoint, this model is of great significance in predicting threshold pressure and researching on the gas–water two-phase flow mechanism in tight sandstone gas reservoirs.

Triple diffusive Marangoni convection in a fluid-porous structure: Effects of a vertical magnetic field and temperature profiles

In this study, the triple diffusive Marangoni convection (TDMC) problem when a steady heat source is present in both layers and a vertical uniform magnetic field in a fluid-porous structure is investigated in closed form. The horizontally infinite fluid-porous structure, which is horizontally surrounded by adiabatic boundaries and subjected to basic uniform and non-uniform temperature profiles. For all three temperature profiles (TP), linear, parabolic and inverted parabolic, the eigenvalues, the thermal Marangoni numbers (TMNs) are determined in closed form for lower rigid and upper free boundaries with surface tension, depending on both temperature and concentrations. The effects of relevant parameters on the eigenvalues, hence on TDMC, against depth ratio are attempted for all TPs. It is noticed that, the inverted parabolic TP on TDMC in a composite layer is the most stable of all the three TPs, the linear TP is the most unstable one and the parabolic TP is the moderate one. The relevant physical parameters considered in the study are effective for porous layer dominant fluid-porous structures.

Flight-to-Wind-Tunnel Correlation Study using JAXA’s Flying Test Bed “Hisho”

Predicting aircraft flight performance using ground tests is important for development but difficult, and flight-to-wind-tunnel correlation methods have been developed and improved over many years. This paper examines the flight-to-wind-tunnel correlation of the aerodynamic characteristics of the Japan Aerospace Exploration Agency’s (JAXA) “Hisho” Flying Test Bed by applying typical methods to flight test data. It was found that the minimum drag coefficient of a business jet geometry test model follows the gradient of the Schoenherr equation well for forced turbulent flows. After that, the reference condition for the correlation was set, but discrepancies in the lift and drag coefficients remained between the flight and wind tunnel tests. A preliminary study identified force differences parallel to the axis of the engine nacelle as being caused by spillage drag due to the difference in the capture area ratio (CAR) between the flight and wind tunnel tests. However, the test data were insufficient to reasonably attribute the difference in the normal force component to lift yielded by the engine nacelle. This was due to the fact that the flight test parameters showed an interdependency and the effects of relevant parameters were not fully investigated in wind tunnel tests.

Effect of near -symmetric potentials on nonlinear modes for higher-order generalized Ginzburg–Landau model

In this paper, we study the higher-order generalized Ginzburg–Landau model which contributes to describing the propagation of optical solitons in fibers. By means of the Hirota bilinear method, the analytical solutions are obtained and the effect of relevant parameters is analyzed. Modulated by the near parity-time-symmetric potentials, the nonlinear modes with 5% initial random noise are numerically simulated to possess stable evolution. Furthermore, the evolution of nonlinear modes is displayed through the adiabatical change of some parameters. The investigation of the present work is intended as a contribution to the work for the higher-order generalized Ginzburg–Landau model.

A Significant Role of Activation Energy and Fourier Flux on the Quadratically Radiated Sphere in Low and High Conductivity of Hybrid Nanoparticles

Fluid flow through a sphere has practical applications in numerous areas of technology, for instance, mineralogy, food engineering, and oilfield drilling. The goal of this paper is to look at how quadratic thermal radiation and activation energy affect the dissipative flow of hybrid nanofluids around a sphere with the heat source parameter. bvp4c (a MATLAB in-built function) is used to solve a system of nonlinear ordinary differential equations, which is the transformed version of the system of governing equations. Using multiple linear regression, the effects of relevant parameters on the mass transfer rate, the Nusselt number, and the skin friction coefficient are investigated. The key findings of this study are that increasing the radiation parameter improves the fluid temperature and increasing the activation energy parameter improves the fluid concentration. When the Eckert number and the parameter of the heat source are increased, the convective heat transmission is reduced. It appears that the magnetic field parameter reduces the shear stress near the surface. It is discovered that increasing the volume percentage of nanoparticles increases the skin friction coefficient and increasing the Schmidt number increases the mass transfer rate. Furthermore, the current results are validated against previously published data.

Numerical investigation of buoyancy-induced thermo-fluid characteristics of different types of infrared suppression (IRS) devices

The present work reports numerical investigation of natural convection heat transfer characteristics for three different types of infrared suppression (IRS) devices (i.e., conical, cylindrical, and hybrid) by varying Rayleigh number and diameter ratio in the range of 1010-1012, and 1.025–1.5, respectively. The effect of relevant parameters on average Nusselt number and induced air-flow rate through the IRS device has been elucidated graphically. Numerically computed results indicate that the average Nusselt number from IRS device is higher for cylindrical IRS devices for all Rayleigh number when DR>1.05. The average Nu initially increases with diameter ratio, attains the maximum (1.1 ≤ DR ≤ 1.15), and decreases with a further increase in diameter ratio. The Nu is significantly influenced by the diameter ratio of cylindrical and hybrid IRS devices than the conical IRS devices. It has been found that the dimensionless induced mass-flow rate at a particular diameter ratio decrease with the Rayleigh number and is found to be more for conical IRS device. In addition, correlation for the average Nusselt number as function of relevant input parameters has been proposed. The cooling time estimation based on lumped parameter analysis shows a faster cooling rate for cylindrical IRS devices followed by hybrid and conical IRS devices.

The significance of exponential space-based heat generation and variable thermophysical properties on the dynamics of Casson fluid over a stratified surface with non-uniform thickness

Stratification is characterized as having applications in a variety of energy storage disciplines, including solar thermal energy usage systems. The effect of heat production, magnetic field, and varied fluid characteristics on the flow of Casson fluid across unstratified and stably stratified paraboloid of revolution is investigated in this work. The velocity index is suitable to describe the fluid flow on an upper horizontal surface of a paraboloid of revolution. It is imperative to mention that the upper horizontal surface of a paraboloid of revolution is likened to the pointed surface of an aircraft which is also described as a surface with variable thickness. The governing partial differential equations are transformed into the nonlinear ordinary differential equations using the similarity transformation. The dimensionless nonlinear ordinary differential equations are solved with the help of the Bvp4c numerical algorithm. The effects of relevant parameters are revealed on various profiles and discussed. It is observed that both the temperature and concentration distributions decrease with increase in thermal stratification and solutal stratification parameters when the velocity index parameter

An Analytical Method for the Assessment of Asset Price Changes in Capital Market

The success of any investment depends mainly on the value of asset which propels the entire financial strength of the organization. Therefore, the impacts on the value of asset prices of investors in capital market were analyzed; using four investment equations which were solved analytical by adopting the separable variable and Ito’s lemma respectively. The computational and graphical results of stock variables and the effect of relevant parameters are well discussed

Development of the family doctor service: an evolutionary game theory analysis

Family physicians play a prominent role in the primary health care system of several countries and regions. This study examined family doctors, community residents, and general hospitals, and found that their behaviour and decisions were inevitably affected by multiple economic concerns. To explore the influence of these economic factors, we established a tripartite evolutionary game model. Based on this dynamic game model, we examined the equilibrium of their interactions, effects of relevant parameters, and evolution trends of different scenarios. The main result shows that the participation of general hospitals is crucial to the construction of the family doctor service; that is, to develop the family doctor service, the government should focus on financial compensation for general hospitals rather than for family doctors. We further concluded that the compensation mechanism of contracted services plays a vital role in attracting physicians’ participation; thus, policymakers should consider these in different stages of the promotion of the family doctor service.