Fluid Temperature Distribution Research Articles

Thermo diffusion impacts on the flow of second grade fluid with application of (ABC), (CF) and (CPC) subject to exponential heating

The aim of this article is to investigate the exact solution by using a new approach for the thermal transport phenomena of second grade fluid flow under the impact of MHD along with exponential heating as well as Darcy’s law. The phenomenon has been expressed in terms of partial differential equations, then transformed the governing equations in non-dimentional form. For the sake of better rheology of second grade fluid, developed a fractional model by applying the new definition of Constant Proportional-Caputo hybrid derivative (CPC), Atangana Baleanu in Caputo sense (ABC) and Caputo Fabrizio (CF) fractional derivative operators that describe the generalized memory effects. For seeking exact solutions in terms of Mittag-Leffler and G-functions for velocity, temperature and concentration equations, Laplace integral transformation technique is applied. For physical significance of various system parameters on fluid velocity, concentration and temperature distributions are demonstrated through various graphs by using graphical software. Furthermore, for being validated the acquired solutions, accomplished a comparative analysis with some published work. It is also analyzed that for exponential heating and non-uniform velocity conditions, the CPC fractional operator is the finest fractional model to describe the memory effect of velocity, energy and concentration profile. Moreover, the graphical representations of the analytical solutions illustrated the main results of the present work. Also, in the literature, it is observed that to derived analytical results from fractional fluid models developed by the various fractional operators, is difficult and this article contributing to answer the open problem of obtaining analytical solutions the fractionalized fluid models.

Dynamic thermal analysis and creep-fatigue lifetime assessment of solar tower external receivers

This paper proposes a methodology for the dynamic thermal analysis of solar tower external receivers and for the assessment of their lifetime. A dynamic thermal model is implemented in Modelica to assess the temperature distributions of receiver tubes and heat transfer fluid (HTF), considering real weather data with a 10-minute time resolution and PI controllers based mass flow rate control. Three representative days are simulated, and the resulting tubes temperature distributions are used to assess the elastic stresses distributions during the investigated days. Subsequently, the creep-fatigue lifetime of each receiver panel is evaluated accounting for material plasticity and creep-induced stress relaxation. The developed methodology is applied to compare three materials for solar receivers: Inconel 740H, Haynes 230, and Incoloy 800H.Results show that fatigue can be negligible with respect to creep for all investigated materials and the shortest lifetime is obtained for 800H, followed by H230, and 740H. The approximation of a receiver operation for 365 clear-sky days per year leads to errors around 30 % on the lifetime. For 740H and 800H, the damage accumulation during cloudy days with high DNI peaks is greater than during clear-sky days due to the remarkable creep damage originated during temperature spikes which follow clouds passages. H230 instead, accumulates more creep damage during clear-sky operation. This emphasizes the potential of the developed methodology to compare different HTF mass flow rate control strategies as well as receiver geometries and materials, HTFs, and heliostats aiming strategies, accounting for the trade-off between energy yield and receiver lifetime.

Transient three-dimensional magnetohydrodynamic flow of heat and mass transfer of a Casson nanofluid past a stretching sheet with non-uniform heat source/sink, thermal radiation and chemical reaction

This study considered the effect of chemical reaction on transient magnetohydrodynamic flow of heat and mass transfer of a Casson nanofluid past a stretching sheet with non-uniform Heat Source/Sink. The highly nonlinear partial differential equations governing the fluid flow alongside its boundary conditions are formulated and suitable similarity variables are introduced to transform the nonlinear partial differential equations into a set of coupled ordinary differential equations. The results revealed that as the Casson fluid parameter increases, the yield stress reduces thereby reducing the velocity, temperature, and concentration profiles. Magnetic parameter, chemical reaction parameter, stretching ratio parameter and unsteadiness parameter can be used to adjust the fluid velocity, temperature and concentration distributions. The effects of local skin friction coefficients, local Nusselt and Sherwood numbers are also shown and considered using tables. The results revealed that the unsteadiness parameter, Casson fluid parameter and magnetic parameter reduces the momentum boundary layer thickness along x and y direction. The work provides physical insight into the thermo-fluidic flow phenomena of Casson nanofluid under the impacts of magnetic field, internal heat generation and chemical reaction.

Unsteady oblique stagnation-point flow and heat transfer of fractional Maxwell fluid with convective derivative under modified pressure field

Unsteady oblique stagnation-point flow and heat transfer of fractional Maxwell fluid with convective derivative towards an oscillating tensile plate are discussed in this paper. The fractional operator is introduced to material derivative for the first time to obtain a newly defined constitutive equation of Maxwell fluid. The Fourier's law is modified accordingly. The pressure gradient is innovatively obtained by solving the differential equation, which bases on the momentum equation away from the plate. Furthermore, the numerical solutions are acquired by virtue of the finite difference method combined with L1-algorithm. It turns out to be convergent through constructing numerical example. The influence of related parameters on the velocity and temperature are performed graphically in detail. Results show that the fluid velocity and temperature distributions tend to periodic oscillation near the plate. Both the velocity and the temperature reduce with the augment of fractional derivative parameters, which indicates the velocity and the temperature boundary layer become thinner. The smaller velocity relaxation time parameter leads to enhanced velocity, meaning that the pressure promotes the fluid velocity. It is evident that all the temperature curves have a tendency to increase first and then decrease with the diverse parameters due to the thermal relaxation characteristic.

3D-numerical predictions of flow structure and heat transfer behavior in heat exchanger tubes inserted with different patterns of double-V baffles

3D-simulation of convective heat transfer and laminar flows at an isothermal wall of a circular tube heat exchanger (CTHE) inserted with different configurations of double-V baffles (DVB) are presented. The insertion of DVB is done with the objective to produce vortex flows and impinging flows to perturb the thermal boundary layer (TBL) over the isothermal wall, thus increasing convective heat transfer coefficient and efficiency. Various DVB parameters which contribute to the best thermal efficiency are considered. Effects of six DVB shapes (Type A-F), DVB height (b/D = 0.05–0.30) and flow directions (+x, -x) on air stream and thermal mechanisms with Reynolds number within 100–2000 (calculated with the inlet condition) are compared. Simulation results of flow structure (streamline structures in transverse planes) and heat transfer characteristics (fluid temperature distributions and local Nusselt number (Nux) contours) are reported. Insights into the flow pattern and heat transfer are key to improve heating and cooling system performance. The improvement of the CTHE inserted with the DVB is presented in terms of the Nusselt number (Nu) and the thermal enhancement factor (TEF), while the pressure loss is presented by the friction factor (f). Simulation results show that the DVB creates vortex and impinging flow over the surface of the circular tubes in the CTHE of all investigated tests. The best TEF and the best Nusselt number ratio are 3.55 and 22.42, respectively.

Investigation of Fluid Flow in Biodiesel Reactor with 4 Different Types of Agitator using Computational Fluid Dynamics Simulation

Biodiesel is formed by transesterification reaction of vegetable or animal fatty acid with alcohol. Agitation of fluid in the biodiesel reactor is required for occurring of the transesterification reaction. This research aims to study the flow behaviour in reactor with different type of agitator using computational fluid dynamics simulation and determine the optimum type of agitator in biodiesel production. Flow behaviour which was studied includes temperature and fraction distribution, turbulence intensity, and vorticity of fluid. The study was conducted in transient and steady state simulation with agitation types of helical screw, turbine, propeller, and anchor. The material that was modelled consist of cooking oil and methanol with mole ratio of 1:6. The mixing process used 500 rpm agitation speed and 60-65 oC mixing temperature. Furthermore, to determine the optimum agitator, the analytical hierarchy process method was carried out. The simulation results were analysed then obtained the score of each agitator, which were 0.314 (anchor), 0.350 (helical screw), 0.249 (propeller) and 0.087 (turbine). Based on the result, the optimum agitator was the helical screw type.

Two-Phase Flow of Eyring–Powell Fluid with Temperature Dependent Viscosity over a Vertical Stretching Sheet

In this work, the mixed convection flow of non-Newtonian Eyring–Powell fluid with the effects of temperature dependent viscosity (TDV) were studied together with the interaction of dust particles under the influence of Newtonian Heating (NH) boundary condition, which assume to move over a vertical stretching sheet. Alternatively, the dusty fluid model was categorized as a two-phase flow that consists of phases of fluid and dust. Through the use of similarity transformations, governing equations of fluid and dust phases are reduced into ordinary differential equations (ODE), then solved by efficient numerical Keller–box method. Numerical solution and asymptotic results for limiting cases will be presented to investigate how the flow develops at the leading edge and its end behaviour. Comparison with the published outputs in literature evidence verified the precision of the present results. Graphical diagrams presenting velocity and temperature profiles (fluid and dust) were conversed for different influential parameters. The effects of skin friction and heat transfer rate were also evaluated. The discovery indicates that the presence of the dust particles have an effect on the fluid motion, which led to a deceleration in the fluid transference. The present flow model can match to the single phase fluid cases if the fluid particle interaction parameter is ignored. The fluid velocity and temperature distributions are always higher than dust particles, besides, the opposite trend between both phases is noticed with β. Meanwhile, both phases share the similar trend in conjunction with the rest factors. Almost all of the temperature profiles are not showing a significant change, since the viscosity of fluid is high, which can be perceived in the figures. Furthermore, the present study extends some theoretical knowledge of two-phase flow.

Mixed convection flow of an electrically conducting viscoelastic fluid past a vertical nonlinearly stretching sheet

The study of hydromagnetic mixed convection flow of viscoelastic fluid caused by a vertical stretched surface is presented in this paper. According to this theory, the stretching velocity varies as a power function of the displacement from the slot. The conservation of energy equation includes thermal radiation and viscous dissipation to support the mechanical operations of the heat transfer mechanism. Through the use of an adequate and sufficient similarity transformation for a nonlinearly stretching sheet, the boundary layer equations governing the flow issue are converted into a set of ordinary differential equations. The Keller box technique is then used to numerically solve the altered equations. To comprehend the physical circumstances of stretching sheets for variations of the governing parameters, numerical simulations are made. The influence and characteristic behaviours of physical parameters were portrayed graphically for the velocity field and temperature distributions. The research shows that the impact of the applied magnetic parameter is to improve the distribution of the viscoelastic fluid temperature and reduce the temperature gradient at the border. Temperature distribution and the associated thermal layer are shown to have improved because of radiative and viscous dissipation characteristics. Radiation causes additional heat to be produced in liquid, raising the fluid's temperature. It was also found that higher velocities are noticed in viscoelastic fluid as compared with Newtonian fluid (i.e., when K = 0).

Numerical analysis of hybrid nanofluid natural convection in a wavy walled porous enclosure: Local thermal non-equilibrium model

A numerical study of the Buoyancy-driven flow in a porous enclosure, having a bottom heated wavy wall, filled with Cu-Al2O3/water hybrid nanofluid is performed using the local thermal non-equilibrium model. The non-dimensional governing equations of fluid flow and heat transfer are solved using the Galerkin finite element method. The state variables change in the porous enclosure is represented using the Darcy-Brinkman model. The impacts of various effective parameters which include nanoparticle volume fraction (0 ≤ Φ ≤ 0.04), Darcy number (10−5 ≤ Da ≤ 10−2), modified conductivity ratio (0.1 ≤ γ ≤ 1000), the number of undulations (1≤ N ≤ 5) and the amplitude of waviness (0.05 ≤ A ≤ 2). The results showed that the Darcy number is the first controlling parameter on the fluid flow and temperature distributions followed by A, N and γ. Additionally, the heat transfer rate is increased by increasing the thermal conductivity of the nanoparticles reaching its maximum value at Φ = 0.04. Furthermore, by comparing the temperature fields of the fluid phase and solid matrix, it is clear that the effects of the local thermal non-equilibrium are significant at a low modified thermal conductivity ratio and high Darcy number.

Influence of Shape Factor and Non-Linear Stretching of the Bullet-Shaped Object on the Mixed Convection Boundary Layer Flow and Heat Transfer with Viscous Dissipation and Internal Heat Generation

The two-dimensional incompressible axisymmetric mixed convection magnetohydrodynamic fluid flow and energy transfer over a bullet-shaped object with a non-linear stretching surface have been investigated. The main goal of this problem is to discuss the effect of the shape and size of the bullet-shaped object on the fluid velocity and temperature distributions. The present analysis has been performed in about two cases ε=0.0 and 2.0. Therefore, fluid velocity and temperature distributions have been investigated in two types of flow geometries such as the thicker surface (s ≥ 2) and the thinner surface (0 < s < 2) of the bullet-shaped object. The equations for momentum and heat transfer have been converted into ODEs by using suitable local similarity transformations. These equations have been performed with a recently developed spectral quasi-linearization method (SQLM). This method helps to identify the accuracy, validity, and convergence of the present solution. The novelty of the present work has been applying the recently developed numerical method to solve these highly nonlinear differential equations. The investigation shows that in the case of a thicker bullet-shaped object (s ≥ 2) the velocity and temperature profiles do not converse the far-field boundary condition asymptotically but cross the axis with an upright angle and the boundary layer structure has no definite shape whereas in the case of a thinner bullet-shaped object (0 < s < 2) the velocity profile converge the ambient condition asymptotically and the boundary layer structure has a definite shape. The innovation of this current work lies in the unification of relevant physical parameters into the governing equations and trying to explain how the flow properties are affected by these parameters.

Structural Design and Lubrication Properties under Different Eccentricity of Magnetic Fluid Bearings

As a lubricant, the viscosity of the magnetic fluid changes with the external magnetic field, which improves the bearing capacity of the oil film and hence the lubrication effect, and has a promising application in bearings. Based on the Roelands viscosity theory, the Shliomis model is used to derive the viscous temperature, viscous pressure, and magnetic viscosity characteristics of magnetic fluids under the influence of an applied magnetic field, and further proposes a structural model of magnetic fluid lubricated bearings to investigate the pressure, temperature and magnetic intensity distribution of magnetic fluids under different eccentricity conditions. The results show that the viscosity of the magnetic fluid decreases exponentially with increasing temperature, rises linearly with increasing pressure, and increases and stabilizes with increasing magnetic induction strength. Because the minimum film thickness point is the dividing point between the convergent wedge and the dispersed wedge, the pressure distribution of the lubricant film separates high pressure from low pressure at the minimum film thickness, and the differential pressure increases with the increase in eccentricity. The temperature distribution of the high-temperature zone is mainly distributed in the middle of the film, and the minimum film thickness zone and the maximum temperature increases with the increase in eccentricity. The magnetic intensity distribution of the strong magnetic field is mainly concentrated in the minimum film thickness zone, and the magnetic induction intensity increases with the increase in eccentricity. The results of this study have certain research significance for solving the problem of the poor lubrication effect of bearing lubricant due to high temperature.

No-vacuum Mono-Tube Compound Parabolic Collector Receiver for Linear Fresnel Concentrator: Numerical and Experimental Approach for Dynamic Behavior Assessment

The present paper aims to develop a novel simplified transient model to investigate the dynamic behavior of a no-vacuum mono-tube receiver equipped with a compound parabolic collector. Considering the intermittency of solar radiation, predicting receiver thermal behavior is critical for linear Fresnel concentrator design and operation. From this standpoint, this research focuses on determining whether or not the steady-state assumption influences the receiver’s performance. Unlike the current models accounting for all the receiver components, the proposed model considers the absorber tube as the primary node and focuses on the heat transfer fluid temperature distribution. The remaining components form an equivalent thermal resistance through which heat loss occurs. The global heat losses are then characterized using an experimental receiver prototype with tube diameter of 70 mm, an aperture of 500 mm, and a secondary reflector. The overall receiver heat loss coefficient was determined at different absorber temperatures ranging between 60 and around 265 °C. The heat loss coefficients measured varied from 4.7 to 8.5 W/m2 K. The model computes receiver performance using the measured overall heat loss coefficient based on real solar data. The receiver response at steady and transient states has been conducted and discussed according to several design parameters, including the heat transfer fluid nature and mass flow rate, the receiver length, and the absorber tube thickness. For the same working conditions, synthetic oils fluid allows achieving higher efficiencies whereas molten salts enable reaching higher outlet temperatures. For the metal wall thicknesses ranging between 2 and 3 mm and the fluid outlet temperature varying between 250 and 300 °C, the receiver thermal efficiency during the day remains relatively close to 75 %. The impact of the absorber tube thermal inertia has been investigated by analyzing the dynamic behavior under various close-to-real-world scenarios. Results have shown that the steady-state assumption does not influence if the metal wall tube thickness is lower than 3 mm.

Numerical simulation on fluid flow and temperature prediction of motorcycles based on CFD

The temperature distributions of solid parts in motorcycle is of significance to give an quantitative cooling performance evaluation for assuring the feasible running of motorcycles. Therefore, the present work mainly tend to systematically investigate the flow velocity distributions and temperature distributions of motorcycle by constructing a fluid-solid coupling analysis model via CFD using commercial software STAR-CCM+. Based on computational fluid dynamics method (CFD), fluid-solid coupling analysis model of motorcycle is realized by integration of porous media model, heat exchanger model and fluid-solid co-simulation module and numerical investigations on fluid flow and temperature distribution characteristics at maximum running speed 120 km/h is conducted. The thermal management experiment test considering three pressure measuring points, fifty-eight temperature measuring points and two flowrate measuring points is investigated to know its cooling performance of motorcycle experimentally and provide experimental data for validation of simulation model. Results show that CFD results are in good agreement with experimental results and the maximum relative error is less than 10%. Thermal management test results show that left and right cylinder temperature, oil temperature are 183 °C, 190 °C, 120 °C, respectively. Air temperature of radiator at inlet side are from 29 °C to 35 °C, Air temperature of radiator at outlet side are from 60 °C to 90 °C, water temperature of radiator inlet and radiator outlet are 96 °C and 89 °C, respectively. The air temperature around left thigh and right thigh are 31 °C and 34 °C, respectively. CFD results show that there is no flow dead-zone and high temperature area in engine main components and muffler front cover. The temperature around motorcycle covering and both two thigh is not high due to the radiation of high-temperature components and the outlet temperature of exhaust muffler is also not high, which will not cause enough heat feelings to the riders for being uncomfortable. From the temperature field analysis results, there is no obvious poor temperature distributions for thermal comfort of this motorcycle. The results of this work can provide simulation data support and theoretical reference for the design and development of motorcycle and its crucial components. Through engineering applications of fluid-solid coupling model in a two-cylinder engine and electric generator, it verifies the universality of fluid-solid coupling model and it can be an effective way for the temperature predictions of industrial products.

Performance assessment of an improved gasifier stove using biomass pellets: An experimental and numerical investigation

This article presents an experimental and computational study of a forced draft cookstove having separate primary and secondary air fans, while utilizing pellets as fuel. A two-dimensional axisymmetric computational fluid dynamics model of the developed cookstove has been created in ANSYS Fluent to analyze the fluid flow, temperature distribution and heat loss from the different parts of the cookstove. The simulation results showed that more than one fourth of the total heat produced by the burning of fuel was being lost to the ambient environment through the outermost wall of cookstove. Also, the temperature of the outer wall of the cookstove was found to be higher than the temperature of secondary air being preheated in the annulus chamber. Therefore, the developed model was further modified by using glass wool insulation which resulted in an increment of 5.7% in thermal efficiency, while the emissions of CO and PM2.5 were reduced by 7.1% and 25.9%, respectively. The performance of the developed models have also been compared with other pellet based forced draft models available globally, and the thermal efficiency of the Mimi Moto cookstove was found to be highest followed by FD 2.2 model.

Impact of asymmetric zeta-potential on natural convection flow in a vertical microannulus with electroosmotic and Joule heating effects

Analytical solutions of temperature distributions and flow formation of joint buoyancy and electroosmotic flow in a vertical microtube formed by two concentric microcylinders are presented. The central equations describing flow formations and thermal energy are offered and solved in closed-form in terms of modified Bessel’s function of first and second kinds. These solutions have significant application in predicting and analyzing flow formation and thermal behavior of Newtonian fluids in micropumps and microchips. Based on the exact solutions obtained, the effects of flow parameters are clearly explained with the use of line graphs. Based on the simulation of results using MATLAB, it is found that fluid temperature distributions and fluid velocity in the vertical microannulus could be enhanced by increasing the radius ratio of the concentric microcylinders.

Comparative analysis for radiative flow of Cu–Ag/blood and Cu/blood nanofluid through porous medium

In this study, the (Cu, Ag) hybrid nanomaterials model is implemented in blood flow equations to investigate its effects on the flow patterns. An analysis for thermal transport is also performed through the melting heat transfer phenomenon. The effects of thermal radiation with Ohmic and viscous dissipation are also considered to explore in heat transport mechanism. Such formulations are going to produced PDEs by combining physical phenomenon through a permeable porous surface. Then, the governing equations are handled using the appropriate similarity transformations to obtain the coupled differential equations system, which is then numerically solved through the bvp4c scheme for dual solutions. The effects of various controlling parameters on fluid velocity and temperature distribution, as well as skin friction coefficient and heat transportation rate, are graphically depicted. According to the obtained findings, in comparison to the nanofluid, the velocity and heat transfer of the hybrid nanofluid model have significant impacts. This study reveals that the performance of the hybrid-nanofluid is more significant to that of the regular nanofluid. In limiting cases, the current results are also compared to those of the previous studies.

The Impact of Reduced Gravity on Oscillatory Mixed Convective Heat Transfer around a Non-Conducting Heated Circular Cylinder

The present analysis addresses the impact of reduced gravity and magnetohydrodynamics on oscillating mixed-convective electricallyconducting fluid flow over a thermal, non-conducting horizontal circular cylinder. In reduced gravity, buoyancy forces may induce fluid motion due to a weak gravitational field but in non-gravity forces, fluid motion can be induced by a variety of factors, including surface tension and density variations. The fluid motion is governed by connected nonlinear partial differential equations which are converted into convenient equations by applying a finite-difference scheme with the primitive transformation and a Gaussian elimination technique. The numerical solutions of the connected dimensionalized equations were obtained for various emerging dimensionless parameters, reduced gravity parameter Rg, Prandtl number Pr, and some other fixed parameters. First, the fluid velocity, temperature distribution and magnetic-field profiles were obtained and then these profiles were used to examine the oscillating quantities of skinfriction, oscillating heat transfer and oscillating rate of currentdensity. The FORTRAN software was used for the numerical results and these results were displayed on Tech Plot. The fluid velocity and magnetic profile were increased at the π/2 station as reduced gravity increased but the dimensionless temperature of the fluid attained a maximum magnitude as reduced gravity was decreased. The larger amplitude of the oscillating coefficients of τt and τm was concluded with a prominent variation for each λ in the presence of reduced gravity. Physically, this could be because an increase in the decreased gravity parameter impacts the fluid flow’s driving potential along a thermal, non-conducting horizontalcylinder.

Numerical Study of Knocking Combustion in a Heavy-Duty Engine under Plateau Conditions

Diesel engine combustion becomes very rough and can lead even lead to deflagration under high altitude conditions, which is harmful to component durability. In this study, the effects of altitude on the main combustion characteristics—in-cylinder fluid flow, spray behavior, and pressure and temperature distribution—were analyzed with CFD. A numerical model was built on the CONVERGE platform and validated with the optical spray behavior and pressure trace measured by the test bench. The simulation results indicated that the decreases in compression pressure and temperature at 4.5 km led to an over 4 °CA longer ignition delay than those of 1 and 3 km. The combustion efficiency decreased from 90% to 47% when the combustion changed from normal combustion to knocking combustion due to severe spray impingement. The processes of end-gas ignition, sequential combustion, and pressure oscillation in knocking combustion were revealed by the numerical modeling results. These results indicate that super-knocking combustion exists in both spark-ignition (SI) engines and compression-ignition (CI) engines.

Effect of multiple forces on convective micropolar fluid flow in a permeable channel with stretching walls considering second order slip conditions

This paper is intended to study the impact of velocity and thermal slip boundary conditions of order two on MHD buoyancy driven radiative micro-polar fluid in a channel with permeable stretching walls. The governing equations are transformed and solved numerically. Convergence of the numerical results are tested with grid independence test and obtained results are validated by comparing with existing results. The influence of velocity and thermal slip of order two, suction or injection, vortex viscosity, micro-rotation, magnetic and thermal radiation parameters on fluid velocity, microrotation profiles and temperature distributions are discussed over the graphs and tables. It is worth mentioning that second- order velocity and thermal slips dominate the stretchable walls and influence the flow characteristics (axial velocity, micro-rotation and temperature) more prominently. The micro-rotation profile decreases at and increases at of the channel for the first slip. This study is useful in blood rheology and fibre spinning etc. and these findings are highly useful to enhance the effectiveness of catalytic reactors.

Local Thermal Nonequilibrium (LTNE) Modeling of a Partially Porous Channel With Spatial Variation in Biot Number

Abstract The local thermal nonequilibrium (LTNE) model has been used widely for analyzing heat transfer during internal flow through porous media, including when a channel is only partially filled with a porous medium. In such problems, the Biot number describes the rate of convective heat transfer between solid and fluid phases. While uniform Biot number models are commonly available, recent advances in functionally graded materials necessitate the analysis of spatially varying Biot number in such geometries. This paper presents LTNE-based heat transfer analysis for fully developed flow in a channel partially filled with porous medium and with spatially varying Biot number to describe solid-fluid interactions in the porous medium. Fully uncoupled ordinary differential equations for solid and fluid temperature distributions are derived under three different boundary condition models. Solid and fluid temperature fields are presented for a variety of Biot number distributions, including quadratically and periodically varying functions. An explanation of the nature of temperature distribution predictions for such problems is provided. For special cases, the results presented here are shown to reduce to past work on constant Biot number. This work improves the theoretical understanding of porous media heat transfer and facilitates the use of such theoretical models for functionally graded materials.