Convection Phenomena Research Articles

Bejan’s heatline and mulitphysics analysis of double diffusive free convection in a doubly stratified non-Darcian porous enclosure with heat generation

The current article illustrates the characteristics of the MHD free convective transport phenomenon in the thermal and mass stratified fluid-saturated Darcy-Forchheimer porous square cavity under the action of the cross-diffusion (Soret and Dufour effects) heat generation and chemical reaction effects. To acquire the spatial distribution of thermal fluxes along with directional propagation in chemically reactive and heat generative non-Darcy fluid flow, a newly developed heatline model for multi-force effect following the heat function theory is proposed in this study. In addition to the thermal profile visualization tools, the solutal free convective fluid flow fields are visually demonstrated by the massline contours curves using a novel mass-function model analogous to the heat function methodology. On the other hand, for the numerical solution of the non-dimensional form of the partial differential equations governing the study, the finite element method is applied. Moreover, the non-Darcy fluid flow attributes subjected to the multiple forces are graphically portrayed by the streamlines, isotherms, iso-concentrations, cumulative Nusselt/Sherwood number plots, heatlines, and masslines for the related dimensionless parameter. Here, these visuals delineate the contra-rotating fluid flow transition under both the thermal and concentration stratification forces. Especially, forceful retardation in both the thermal and concentration flux’s movements is noticed when magnetic forces are intensified. An upward geometrical shift of the higher concentration region is seen with increasing chemical reaction parameter.

Lightning Prediction Using Electric Field Measurements Associated with Convective Events at a Tropical Location

Nowcasting of lightning occurrences is essential in tropical locations as lightening causes severe damage to life and property. This study attempts to nowcast lightning events during convective phenomena using an electric field monitor (EFM) at a tropical urban location, Kolkata (22.65°N, 88.45°E). Before the onset of heavy lightning occurrences, definite changes in the atmospheric electric field (EF) are observed, which in turn are associated with high cloud liquid water content (LWC) and low cloud base height (CBH). A model has been proposed to nowcast lightning strikes within about 17.5 km radius of the present location based on the EF standard deviation (EFSD) values. The proposed technique is tested with the lightning data provided by a collocated lightning detector, which yields a prediction efficiency of ~ 0.91 (~ 0.86), a false alarm rate of ~ 0.23 (~ 0.18), and a critical success index of ~ 0.71 (~ 0.72) with an optimal range of other performance parameters during the monsoon (pre-monsoon) periods, thereby generating an alarm 45 min before lightning events.

Thermal Effects in the End-Winding Region of Electrical Machines

The main heat transfer mechanism in the end-winding region of electrical machines is convection. In order to increase the air motion, the rotor is equipped with a series of blades. Their geometry is reflected in the fanning factor, i.e., the ratio between the rotor peripheral speed and air velocity. An accurate calculation procedure for the fanning factor has not yet been given. Knowing its value is crucial for the determination of air velocity and heat transfer coefficient (HTC), as the latter describes the end-winding heat removal capability. In this study, the convective heat transfer phenomena between the end winding and air inside the end-winding region were analyzed, with the heat generated only in the end winding, mimicked with a custom designed coil, and air moved by the blades. The analysis was performed by experimental testing and computational fluid dynamics (CFD) modeling. Measurements data were used to build a reliable CFD model. Further on, CFD results were used to derive a generalized analytical equation for calculation of the end-winding HTC, related to blade geometry and rotor rotational speed. The developed analytical model significantly improves the quality of real-time lumped circuit thermal modeling of electrical machines and, thus, enriches this field of science.

Theoretical Analysis of a Nonequilibrium Transport Model of Two-Dimensional Nonisothermal Reactive Chromatography Accounting for Bi-Langmuir Isotherm.

The current study investigates a nonequilibrium and nonlinear two-dimensional lumped kinetic transport model of nonisothermal reactive liquid chromatography, considering the Bi-Langmuir adsorption isotherm, heterogeneous reaction rates, radial and axial concentration variations, and the adsorption and reaction enthalpies. The mathematical models of packed bed chromatographic processes are expressed by a highly nonlinear system of coupled partial differential algebraic equations connecting the phenomena of convection, diffusion, and reaction, for mass and energy balance, the differential algebraic equations for mass balance in the solid phase, and the algebraical expressions for the adsorption isotherms and for the reaction rates. The nonlinearity of the reaction term and the adsorption isotherm preclude the derivation of an analytical solution for the model equations. For this reason, a semidiscrete, high-resolution, finite-volume technique is extended and employed in this study to obtain the numerical solution. Several consistency checks are performed to evaluate the model predictions and analyze the precision of the proposed numerical scheme. A number of heterogeneously catalyzed stoichiometric reactions are numerically simulated to examine reactor performance under the influence of temperature and Bi-Langmuir adsorption dynamics, the level of coupling between mass and energy fronts, and to study the effects of various critical parameters. The numerical results obtained are beneficial for optimal predictive control and process optimization during production and the development of methods for systematic design and fault detection of nonisothermal liquid chromatographic reactors, and hence constitute the first step to provide deeper insight into the overall evaluation of integrated reaction and separation processes.

Mathematical modeling of drying characteristics for cylindrical Thompson seedless grapes under natural convection

AbstractThe objective of this paper is to develop a universal diffusion model of drying kinetics that can be applied to a variety of shrinkable products such as fruits and vegetables. The main objective is to examine the physical changes that occur during convective air‐drying process of Thompson seedless type cylindrical grapes. These include changes in the physical properties of the product, such as the moisture content, the temperature of the product, and the size of the product. The authors develop a two‐dimensional transient diffusion model and MATLAB that takes into account convection, radiation, and evaporation phenomena under a variety of operating conditions for simulating grape drying and shrinkage. The differential equations are solved for moisture transfer within a cylinder using the finite difference method. A lab‐scale experimental test setup has also been developed and tests are performed. The results obtained from the mathematical model are compared with experimental results and found to be in agreement with a maximum error of 14%. The model is also validated with the results reported in the literature. Meteorological data are used to determine the time‐dependent radiation flux density (I(t)) on a particular day. For each of the investigated conditions, the effective moisture diffusivity (Deff) is determined using Fick's diffusion equation. Volume reduction of a product due to drying process was assumed to be equivalent to moisture removal. A coefficient of effective diffusivity was calculated using drying data collected at constant cabin air temperatures between 50 and 70°C. The maximum radius and length of the grape were reduced by 40.33% and 42.40%, respectively, when the size of the grape was considered to be 6.5 mm radius and 25 mm length. The results of the present mathematical model may be useful for accurately predicting the temperature, moisture content, and size change of the product.Practical ApplicationDrying food to preserve it is an energy‐intensive process. Solar drying is one of the oldest methods used to preserve agricultural produce. Solar thermal energy has tremendous potential for commercial and industrial drying applications with air temperatures as high as 80°C. Solar drying is prevalent in India because farmers have easy access to solar drying systems. Through the installation of such a system, agricultural products can be dried in agricultural regions. This work provides farmers with added value for their particular products. Solar dryers system ensure significant fossil fuel energy savings. Solar dryers must meet rigorous requirements for dependability and continuous operation. This research contributes to the design, optimization, and control of food drying processes. For each drying time, the extent of moisture distribution, product temperature, and product size are determined. For dryers operating under a variety of operating conditions, this aids in system performance forecasting. In addition, the effect of interior cabin temperature variation is investigated, which aids in identifying drying characteristics.

Fractionalizing, coupling and methods for the coupled system of two-dimensional heat diffusion models

<abstract><p>The present manuscript gives an overview of how two-dimensional heat diffusion models underwent a fractional transformation, system coupling as well as solution treatment. The governing diffusion models, which are endowed with Caputo's fractional-order derivatives in time $ t $, are suitably coupled using the (1) convection phenomenon, (2) interfacial coupling by considering the mechanism of a double-layered bar, and the (3) nonlinear coupling due to temperature-dependent thermal diffusivities. Semi-analytical and analytical methods are considered for the solution treatment. Moreover, we seek a computational environment to graphically illustrate the systems' response to different fractional orders in each case through the determined diffusional fields. Besides, we supply certain concluding notes at the end.</p></abstract>

A COMPARATIVE HEAT TRANSFER STUDY OF WATER AND LIQUID GALLIUM IN A SQUARE ENCLOSURE UNDER NATURAL CONVECTION

A comprehensive comparison of fluid flow and heat transfer characteristics inside a square enclosure with water or liquid gallium as fluids under natural convection has been studied numerically in the laminar flow regime. The left and right walls of the square cavity are treated as hot and cold isothermal walls, respectively, while the other walls are kept adiabatic. A 2D problem is considered, and the buoyancy term in the momentum equation is represented by the Boussinesq approximation. The governing equations are solved using finite difference methods. The convective terms are evaluated by using sixth-order compact schemes. Results are shown in the form of isotherms, streamlines, temperature profiles, average Nusselt number, average heat transfer coefficient values, and average skin friction values for various Grashof numbers (Gr) ranging from 10<sup>3</sup> to 10<sup>6</sup>. The present solver is validated against numerical and experimental work published in the literature. From the study, it is observed that the flow and heat transfer characteristics of conventional fluids like water differ significantly from low Prandtl number fluids like liquid gallium. Results show that the diffusion mechanism is dominant compared to convection in liquid gallium as a fluid for Gr ≤ 10<sup>4</sup> but the convection phenomenon is dominant in water as a fluid for all Grashof numbers. The comparison shows that at a Grashof number of 10<sup>3</sup> liquid gallium has 25.61 times greater heat transfer than water. Finally, a correlation for the average Nusselt number is developed with liquid gallium as fluid for a Grashof number ranging from 10<sup>3</sup> to 10<sup>6</sup>.

THERMO-FLUIDIC CONVECTIVE FLOW STUDY OF HYBRID NANOFLUID IN AN INVERTED T-SHAPED POROUS ENCLOSURE UNDER UNIFORMLY ACTING MAGNETIC FIELD

This research work attempted to analyze the impact of a magnetic field having various inclination angles on the hydrothermal convective flow and heat transport phenomena in an inverted T-shaped porous enclosure saturated with water-based hybrid nanofluid. Firstly, a comparative study for accessing the significance and applicability of the hybrid nanofluid over simple fluid (water) is accomplished at various Rayleigh numbers. Furthermore, the generalized Darcy-Forchheimer-Brinkmann model having magnetic forces is numerically simulated through the penalty finite element approach. The complete study covers the parametric studies in the presence and absence of magnetic field for parameters, including the broad-ranging values of Hartmann number (Ha), inclination angles of magnetic field (ζ), Rayleigh number (Ra), porosity (∈), and Darcy number (Da). Moreover, results obtained from the parametric studies are graphically demonstrated through the isotherms, streamlines, and the variation of mean Nusselt number plots (Nu<sub>m</sub>). The results variation suggests that the heat transfer rate is getting more robust with Da, Ra, and ∈, though the appearance of the magnetic field restricts the fluid flows and heat transport. Additionally, the increasing angle supports the heat transfer process till ζ = 30 up to some extent, and further, it deteriorates till ζ = 90. Thus, a proper inclination and the magnitude of the magnetic field may be a better choice to control the flow regime and the thermal transport phenomena inside the porous domain.

Strong effect of fluid rheology on electrokinetic instability and subsequent mixing phenomena in a microfluidic T-junction

When two fluids of different electrical conductivities are transported under the influence of an electric field, the electrokinetic instability (EKI) phenomenon often triggers in a microfluidic device once the electric field strength and conductivity gradient exceed some critical values. This study presents a detailed numerical investigation of how the rheological behavior of a fluid obeyed by the non-Newtonian power-law constitutive relation could influence this EKI phenomenon in a microfluidic T-junction. We find that as the fluid rheological behavior changes from shear-thickening (n >1) to shear-thinning (n <1), the EKI phenomenon is significantly influenced under the same conditions. In particular, the intensity of this EKI phenomenon is found to be significantly higher in shear-thinning fluids than in Newtonian and shear-thickening fluids. Also, the critical value of the applied electric field strength for the inception of this EKI phenomenon gradually increases as the fluid rheological behavior progressively moves from shear-thinning to shear-thickening. The corresponding mixing phenomenon, often achieved using this EKI phenomenon, is also notably higher in shear-thinning fluids compared to Newtonian and shear-thickening fluids. A detailed analysis of both the flow dynamics and mixing phenomena inside the microdevice is presented and discussed in this study. To perform so, we also employ the data-driven dynamic mode decomposition technique, considered one of the widely used reduced-order models to analyze a dynamical system. This analysis facilitates a better understanding of the EKI-induced chaotic convection and mixing phenomena inside the microdevice. We observe that the spatial expanse and intensity of the coherent flow structures differ significantly as the power-law index changes, thereby providing valuable insight into certain aspects of the underlying flow dynamics that, otherwise, are not apparent from other analyses.

Improvement of natural convection simulation based on energy conservation dissipative particle dynamics

Energy conservation dissipative particle dynamics (eDPD) is a mesoscale numerical simulation method of studying the heat transport process. In previous studies, when the Boussinesq assumption was introduced into the eDPD system to study the natural convection, the system was generally considered to be incompressible, and the effect of the thermal expansion of the eDPD system itself on the simulation results was often neglected, which would cause errors in the simulation. In the present study, the thermal expansion characteristic of the eDPD system is first investigated, and the thermal expansion coefficient <i>β</i> of the eDPD system is obtained by eDPD simulation. Then, based on the thermal expansion characteristic of the eDPD system itself, the natural convection is simulated with different values of Rayleigh number <i>Ra</i> and different geometries, specifically, square cavity, concentric rings, and eccentric rings, and reasonable temperature and velocity fields are obtained, and they are in agreement with the simulated results by the finite volume method (FVM). The error between the eDPD simulation, in which the natural convection is driven by thermal expansion of the eDPD system itself, and FVM simulated result is considerably smaller than the errors observed in previous studies where Boussinesq assumption was directly adopted to simulate natural convection phenomena while neglecting the thermal expansion effect of eDPD system. It is shown that the effect of the eDPD system’s own thermal expansion characteristic needs to be considered when introducing the Boussinesq assumption in the eDPD system, and further, the calculation of the <i>Ra</i> number is modified in this paper.

Experimental quantification of heat haze errors in stereo-DIC displacements: Application to thermoplastics thermoforming temperature range

Stereo digital image correlation (Stereo-DIC) is recurrent in photo-mechanics to measure kinematic fields which can be of high interest for instrumenting open-mould forming processes. Nevertheless, in the presence of pre-heating operations, as observed in the context of thermoforming processes, natural convective heat flows risk emerging and causing optical distortions in the recorded images. Consequently, this alters the precision of the measured full-fields of displacements. To address these challenges, this study proposes an experimental approach with two distinctive features. Firstly, it focuses on regenerating the heat haze effect at a laboratory scale within a partially opened vertical enclosure and without utilizing any filtering air flows. Secondly, the study quantifies the spatial and temporal variations of errors through statistical analyses of the differences between measurements obtained from quasi-static speckle translations and known imposed displacements. Experimental results indicate that the main cause of displacement errors is related to the 3D nature of the hot air turbulence caused by the natural convection phenomenon. This observation is supported by the detection of feather-shaped heat flows causing optical out-of-plane surface deviations. Furthermore, the study validates the possibility of obtaining time-dependent corrective functions for bias errors, which characterize the performance of the calibrated Stereo-DIC system in the presence of heat haze. Despite the limitation of extensive measurements required by the proposed approach, this study contributes to addressing the heat haze effect and constitutes a step towards extending the use of stereo-DIC for in-situ instrumentation of short-duration thermomechanical tests in the presence of heat haze.

Non-intrusive diagnostics of differentially-heated two-component immiscible fluid layer with phase change

Experiments on buoyancy-driven convective phenomena in a differentially-heated two component immiscible fluid layer with phase change phenomena have been reported. The real-time mapping of the transients associated with the process has been affected in a complete non-intrusive manner using rainbow schlieren deflectometry. Experiments have been performed for varying heat flux levels supplied to the lower horizontal surface of the cavity and for different heights of the secondary fluid layer. The two-component immiscible fluid mixture comprises of water as the (lighter) primary fluid layer and dichloromethane (DCM) as the (heavier) secondary fluid component. The supplied heat flux levels are sufficient enough to induce phase change in the secondary fluid layer through nucleate pool boiling. In addition to the real-time mapping of the buoyancy-induced convection in both the fluid layers, the process of vapor bubble inception, their growth and departure from the lower heated wall of the cavity have been recorded in the form of time-lapsed schlieren images. Conditions under which the continued interaction of the vapor phase of DCM with the interface leads to interface deformation and its final breakage have been investigated. Based on the force balance analysis, the critical volume of the DCM vapor phase required for interface breakage has been determined. Dependence of parameters such as neck breakage height, time required for interface breakage etc. on the supplied heat flux level and height of the secondary fluid has been investigated. The experimental observations revealed the importance of vapor bubbles-induced fluid agitation in the otherwise stagnant primary fluid layer, disruption of the thermal boundary layer in a completely passive manner as the upward rising vapor volume condenses at the top horizontal surface of the differentially-heated cavity and their implications in possible heat transfer enhancement.

CFD MODELING OF THE OPTIMIZATION OF A VENTILATION SYSTEM IN ASQUARE ENCLOSURE WITH TWO INLETS

In this article, we have numerically studied the phenomenon of laminar mixed convection in a ventilated square cavity. The vertical walls of the cavity are subjected to a temperature gradient while the horizontal walls are constrained as adiabatic. We used the finite volume method to discretize the system of non-dimensional equations and a purely implicit scheme for the temporal discretization. The results were presented in the form of hydrodynamic and thermal fields for different values ​​of the Richardson number with the number of Reynolds constant. We found that the increase of the Richardson number with a fixed Reynolds number Re=100 allows us to visualize the evolution of the system and to appreciate the efficiency of the bottom ventilation.

Similarity Investigation of Thermosolutal Mixed Convection in a Saturated Porous Medium

This contribution investigates the thermosolutal convection phenomenon around a thin wall, vertically immersed in a fluid saturating a porous medium of non-uniform permeability, taking into account the thermal conditions of the wall which is exposed to a fluid suction/injection. The conservation equations with boundary conditions have been transformed by the similarity method into a set of nonlinear differential equations. The resulting equations are numerically resolved using a fifth-order Runge-Kutta scheme coupled with the shooting technique. A graphical and physical interpretation of the found results as a function of the control parameters was performed. It is noticed that the heat transfer rate and the mass transfer rate at wall, are intensified for free convection and for significant permeability.

Precipitation frequency in Med-CORDEX and EURO-CORDEX ensembles from 0.44° to convection-permitting resolution: impact of model resolution and convection representation

Recent studies using convection-permitting (CP) climate simulations have demonstrated a step-change in the representation of heavy rainfall and rainfall characteristics (frequency-intensity) compared to coarser resolution Global and Regional climate models. The goal of this study is to better understand what explains the weaker frequency of precipitation in the CP ensemble by assessing the triggering process of precipitation in the different ensembles of regional climate simulations available over Europe. We focus on the statistical relationship between tropospheric temperature, humidity and precipitation to understand how the frequency of precipitation over Europe and the Mediterranean is impacted by model resolution and the representation of convection (parameterized vs. explicit). We employ a multi-model data-set with three different resolutions (0.44°, 0.11° and 0.0275°) produced in the context of the MED-CORDEX, EURO-CORDEX and the CORDEX Flagship Pilot Study "Convective Phenomena over Europe and the Mediterranean" (FPSCONV). The multi-variate approach is applied to all model ensembles, and to several surface stations where the integrated water vapor (IWV) is derived from Global Positioning System (GPS) measurements. The results show that all model ensembles capture the temperature dependence of the critical value of IWV (IWVcv), above which an increase in precipitation frequency occurs, but the differences between the models in terms of the value of IWVcv, and the probability of its being exceeded, can be large at higher temperatures. The lower frequency of precipitation in convection-permitting simulations is not only explained by higher temperatures but also by a higher IWVcv necessary to trigger precipitation at similar temperatures, and a lower probability to exceed this critical value. The spread between models in simulating IWVcv and the probability of exceeding IWVcv is reduced over land in the ensemble of models with explicit convection, especially at high temperatures, when the convective fraction of total precipitation becomes more important and the influence of the representation of entrainment in models thus becomes more important. Over lowlands, both model resolution and convection representation affect precipitation triggering while over mountainous areas, resolution has the highest impact due to orography-induced triggering processes. Over the sea, since lifting is produced by large-scale convergence, the probability to exceed IWVcv does not depend on temperature, and the model resolution does not have a clear impact on the results.

The added value of km-scale simulations to describe temperature over complex orography: the CORDEX FPS-Convection multi-model ensemble runs over the Alps

The increase in computational resources has enabled the emergence of multi-model ensembles of convection-permitting regional climate model (CPRCM) simulations at very high horizontal resolutions. An example is the CORDEX Flagship Pilot Study on “Convective phenomena at high resolution over Europe and the Mediterranean”, a set of kilometre-scale simulations over an extended Alpine domain. This first-of-its-kind multi-model ensemble, forced by the ERA-Interim reanalysis, can be considered a benchmark dataset. This study uses a recently proposed metric to determine the added value of all the available Flagship Pilot Study hindcast kilometre-scale simulations for maximum and minimum temperature. The analysis is performed using state-of-the-art gridded and station observations as ground truth. This approach directly assesses the added value between the high-resolution CPRCMs against their driving global simulations and coarser resolution RCM counterparts. Overall, models display some modest gains, but also considerable shortcomings are exhibited. In part, these deficiencies can be attributed to the assimilation of temperature observations into ERA-Interim. Although the gains for the use of kilometre-scale resolution for temperature are limited, the improvement of the spatial representation of local atmospheric circulations and land–atmosphere interactions can ultimately lead to gains, particularly in coastal areas.

Entropy generation study due to MHD double-diffusive convection in the rectangular cavity with built-in rectangular blockage

In the present work, the influence of the aspect ratio of the rectangular cavity (length > width) and the built-in rectangular blockage (length > width) on the local and global entropy generation (EG) characteristics due to double-diffusive convection and external magnetic field have been explored. Particularly, the effect of the pertinent parameters, such as the aspect ratio of the cavity and blockage Lewis number Rayleigh number Hartmann number and buoyancy ratios on the EG characteristics have been explored. The working fluid is considered to be a liquid metal-sodium–potassium alloy (Pr = 0.054). Lattice Boltzmann method numerical scheme is employed to solve the double-diffusive natural convection phenomenon. The increase in Ra induces an enhancement in the localized EG terms, whereas the augmentation in Ha diminishes the local total EG (S Total) for a given Ra. The dominance of thermal and species transport irreversibility in the cavity was noticed for Conversely, for AR = 4, the significance of flow friction irreversibility within the cavity was observed (). The results of the work are also summarized in terms of simpler empirical correlations of and ST , which might be useful for possible engineering design purposes.

A Hybrid, Runtime Coupled Incompressible CFD-CAA Method for Analysis of Thermoacoustic Instabilities

Abstract Thermoacoustic instabilities in gas turbine engines are of increasing interest for design of future low-emission technology combustors. Numerical methods used to predict thermoacoustic instabilities often employ either fully compressible resource-intense computational fluid dynamics (CFD) simulations, or two-step approaches where source terms extracted from CFD simulations are supplied to subsequent computational aeroacoustics (CAA) simulations. This work demonstrates an analysis of self-excited thermoacoustic instabilities using a hybrid method based on runtime coupling of incompressible CFD and CAA simulations. A prior implementation for the computation of combustion noise through one-way coupling of CFD and CAA solvers has been extended to a two-way coupling that allows acoustics to influence the flow field. The resulting hybrid method couples acoustic and convective physical phenomena by using mean flow field quantities and the thermoacoustic energy source term obtained from the solution of the Navier–Stokes equations in the low Mach number limit as an input for the acoustic perturbation equations (APEs). The fluctuating acoustic quantities pressure and velocity obtained from the solution of the APE are in turn included in the solution of the low Mach number Navier–Stokes equations, influencing the convective dynamics of the flow field. The suitability of the present implementation to capture thermoacoustic feedback is demonstrated through analysis of the well-known self-excited instability observed in a Rijke tube. The results are presented and discussed in comparison with a fully compressible reference solution.

Analyzed of Convection Heat Transfer in Cabin Car Equipped With Air Conditioner (AC) Using A Simple Method Assisted by Microsoft Excel

Visualization of heat flow often uses complex and challenging programs such as Matlab and Ansys Fluent with expensive licenses, and the operation is also difficult. This study aims to demonstrate the phenomenon of convection heat transfer in a simple way. The phenomenon of convection is fairly difficult, and the heat transfer process can cause misconceptions in students. An appropriate and easy-to-use method is needed in preparing for classroom learning. This study was conducted to review the air condition in the car cabin, which is influenced by airflow from the air conditioner, and visualize it. This visualization can be used to explain the phenomenon of heat transfer by convection to students, especially while cooling the car's air conditioner. This research was conducted using a car model with three rows of seats where the air conditioner is only on the front cabin dashboard. On the dashboard, the AC flows are located on the left, right, and center. The calculation is carried out by applying the Black Principle, where other particles around it influence the particle temperature. Microsoft Excel is used to perform mathematical operations and visualize the results in graphs. It successfully delivers a 2D image showing heat distribution in the car cabin space. Visualization of this convection phenomenon can provide an overview of the convection flow phenomenon. So, this method is very easy to operate and apply by teachers in preparing lessons on the phenomenon of temperature convection.

Non-Newtonian MHD double diffusive natural convection flow and heat transfer in a crown enclosure

Double diffusion natural convection phenomenon has gained significant attention in different fields of life for example geology, oceanography, metallurgy and astrophysics. The present disquisition is to investigate the mathematical analysis of fluid flow in a waver cavity in the presence of heated circular center of the cavity. The mass and heat transfer on MHD Casson fluid flow are the main focus of current study. The circular center of cavity is kept fixed and heated while the right and left walls of the wavy cavity are cold. The Lorentz force is also taken into consideration. The mathematical problem is governed in form of coupled partial differential equations and is solved by using well know finite element method. Flow distribution analysis is discussed in form of streamlines, isotherms and isoconcentration contour patterns. The obtained results are also represented in the form of kinetic energy, local heat, and mass fluxes. It is noted that under the increasing effect of the Casson parameter rate of heat transfer increase while the rate of mass transfer decrease.