Effect of Magnetic Field on the Flow and Heat Transfer in a Casson Thin Film on an Unsteady Stretching Surface in the Presence of Viscous and Internal Heating

The aim of this investigation is to analyze the effectiveness of Lorentz force, viscous dissipation and internal heating on the heat and flow characteristics of a non-Newtonian Casson fluid thin film resting on a stretching surface under the influence of a magnetic field. Employing suitable similarity variables and shooting technique and integrating scheme numerical solutions for velocity and temperature are obtained. The results of this analysis are compared with the published work and are found to be in good agreement. The thickness of the thin film is evaluated and is observed that Lorentz force and the non-Newtonian nature of the fluid have a thinning influence on the film. Velocity and temperature distributions in the thin film are discussed for various flow parameters.

Numerical Investigation of Micropolar Casson Fluid over a Stretching Sheet with Internal Heating

This theoretical study investigates the microrotation effects on mixed convection flow induced by a stretching sheet. Casson fluid model along with microrotation is considered to model the governing flow problem. The system is assumed to undergo internal heating phenomenon. The governing physical problem is transformed into system of nonlinear ordinary differential equations using scaling group of transformations. These equations are solved numerically using Runge Kutta Fehlberg scheme coupled with shooting technique. Influence of sundry parameters for the case of strong and weak concentration of microelements on velocity, temperature, skin friction and local heat flux at the surface are computed and discussed. Lower skin friction and heat flux is observed for the case of weak concentration(n = 0.5)compared to strong concentration of microelements(n = 0.0) near the wall.

Earth: Review Article

Every year on 22 April, we have celebrated Earth Day and the beautiful planet we call home. Earth Day, established in 1970, has been used to highlight our planet’s environmental challenges and raise awareness of the importance of protecting our world for future generations [1]. To provide the protection of our planet, we should explain Earth’s environmental challenges to the best of our knowledge in frames of contemporary Geophysics. This paper gives a short overview of the developed Hypersphere World-Universe Model (WUM) and pay particular attention to the principal role of Dark Matter (DM) in the Earth’s life. In this manuscript, we discuss different aspects of the Earth: a condition of Young Earth before the Beginning of life on It;Internal Structure;“The 660-km Boundary” that we named Geomagma;Random Variations of Earth’s Rotational Speed on a daily basis;Origin of Moon;Expanding Earth;Internal Heating;Faint Young Sun paradox;Geocorona and Planetary Coronas;High-Energy Atmospheric Physics. WUM proposed principally different ways to solve the problems of Internal Heating, Origin of the Moon, and Faint Young Sun paradox based on DM core of the Earth. The Model revealed the fact that the Sun Activity causes the Geomagma Activity and, as a consequence, Random Variations of Earth’s Rotational Speed by the varying Sun’s magnetic field.

Thermodynamic Performance Analysis of Geothermal Power Plant Based on Organic Rankine Cycle (ORC) Using Mixture of Pure Working Fluids

The selection of working fluid significantly impacts the geothermal ORC’s Efficiency.Using a mixture as a working fluid is a strategy to improve the output of geothermal ORC.In the current study,modelling and thermodynamic analysis of ORC,using geothermal as a heat source,is carried out at fixed operating conditions.The model is simulated in the Engineering Equation Solver(EES).An environment-friendly mixture of fluids,i.e.,R245fa/R600a,with a suitable mole fraction,is used as the operating fluid.The mixture provided the most convenient results compared to the pure working fluid under fixed operating conditions.The impact of varying the evaporator pressure on the performance parameters,including energy efficiency,exergy efficiency and net power output is investigated.The system provided the optimal performance once the evaporator pressure reached the maximum value.The efficiencies:Energy and Exergy,and Net Power output of the system are 16.62%,64.08%and 2199 kW for the basic cycle and 20.72%,67.76%and 2326 kW respectively for the regenerative cycle.

Effects of Heat Clearing and Stasis Resolving Method on PTS,Inflammatory Factors and T-lymphocyte Subsets in Peripheral Blood of URM Patients with Suppressed Internal Heat

[Objectives]To explore the effects of heat clearing and stasis resolving method on prethrombotic state,inflammatory factors and T-lymphocyte subsets in peripheral blood of unexplained recurrent miscarriage(URM)patients with suppressed internal heat.[Methods]Thirty cases of URM patients with suppressed internal heat and 30 normal women were collected,and characteristics of changes in peripheral serum D-dimer(D-D),fibrin degradation product(FDP),fibrinogen(FIB),IL-6,IL-10 and TNF-α,CD,CD,CD,CD,CDlevels were detected.URM patients were treated with traditional Chinese medicine for clearing heat and resolving blood stasis for 3 menstrual cycles,and the changes of indicators before and after treatment were observed.[Results]Compared with normal women,the peripheral serum levels of D-D,IL-6,TNF-αand CDin URM patients with suppressed internal heat were increased(P<0.05),while the IL-10 lymphocyte level was significantly decreased(P<0.05);compared with that before treatment,the contents of D-D,IL-6,TNF-αand CDdecreased after 3 menstrual cycles(P<0.05),while the contents of IL-10 and CDT lymphocytes increased significantly(P<0.05).[Conclusions]The heat clearing heat and stasis resolving method can effectively improve the prethrombotic state of URM,and the action mechanism may be related to the regulation of immune and peripheral blood inflammatory factors.

Classical Linear Stability Analysis of Energy Based Internally Heated Distributions on Bénard Porous Convection in a Micropolar Fluid Layer

The theoretical and numerical analysis is carried out on the effect of three types of configurations of Rayleigh-Bénard (RB) convection driven by the boundary combinations of Rigid-Rigid (R-R), Rigid-Free (R-F) and Free-Free (F-F). The RB convection models are distinguished by the three different temperature boundary conditions like: 1) RB1: lower and upper at fixed-temperature, 2) RB2: lower and upper with fixed-heat flux, or perfectly insulating and 3) RB3: bottom surface is fixed-temperature and top surface is fixed-heat flux. A Galerkin-type is based on the weighted residual method (WRM) which has been used to obtain the eigenvalue for gravity thermal Rayleigh number. It is noted that the porous medium of Darcy parameter and spin diffusion (couple stress) parameter N3 is to hasten coupling parameter N1 and micropolar heat conduction parameter N5 is to delay the onset of convection. Further, increase in the value of N1, N5, and as well as decrease in N3 is to diminish the size of convection cells.

A Study on the Effects of Internal Heat Generation on the Thermal Performance of Solid and Porous Fins using Differential Transformation Method

In this study,the impacts of internal heat generation on heat transfer enhancement of porous fin is theoretical investigated using differential transform method.The parametric studies reveal that porosity enhances the fin heat dissipating capacity but the internal heat generation decreases the heat enhancement capacity of extended surface.Also,it is established that when the internal heat parameter increases to some certain values,some negative effects are recorded where the fin stores heat rather than dissipating it.This scenario defeats the prime purpose of the cooling fin.Additionally,it is established in the present study that the limiting value of porosity parameter for thermal stability for the passive device increases as internal heat parameter increases.This shows that although the internal heat parameter can help assist higher range and value of thermal stability of the fin,it produces negative effect which greatly defeats the ultimate purpose of the fin.The results in the work will help in fin design for industrial applications where internal heat generation is involved.

Boosting methylcyclohexane dehydrogenation over Pt-based structured catalysts by internal electric heating

Methylcyclohexane(MCH)serves as an ideal hydrogen carrier in hydrogen storage and transportation process.In the continuous production of hydrogen from MCH dehydrogenation,the rational design of energy-efficient catalytic way with good performance remains an enormous challenge.Herein,an internal electric heating(IEH)assisted mode was designed and proposed by the directly electrical-driven catalyst using the resistive heating effect.The Pt/Al2O_(3)on Fe foam(Pt/Al2O_(3)/FF)with unique threedimensional network structure was constructed.The catalysts were studied in a comprehensive way including X-ray diffraction(XRD),scanning electron microscopy(SEM)-mapping,in situ extended X-ray absorption fine structure(EXAFS),and in situ COFourier transform infrared(FTIR)measurements.It was found that the hydrogen evolution rate in IEH mode can reach up to above 2060 mmol·gPt^(−1)·min^(−1),which is 2–5 times higher than that of reported Pt based catalysts under similar reaction conditions in conventional heating(CH)mode.In combination with measurements from high-resolution infrared thermometer,the equations of heat transfer rate,and reaction heat analysis results,the Pt/Al2O_(3)/FF not only has high mass and heat transfer ability to promote catalytic performance,but also behaves as the heating component with a low thermal resistance and heat capacity offering a fast temperature response in IEH mode.In addition,the chemical adsorption and activation of MCH molecules can be efficiently facilitated by IEH mode,proved by the operando MCH-FTIR results.Therefore,the as-developed IEH mode can efficiently reduce the heat and mass transfer limitations and prominently boost the dehydrogenation performance,which has a broad application potential in hydrogen storage and other catalytic reaction processes.

Wave Propagation in a Magneto-Micropolar Thermoelastic Medium with Two Temperatures for Three-Phase-Lag Model

The present paper is concerned with the wave propagation in a micropolar thermoelastic solid with distinct two temperatures under the effect of the magnetic field in the presence of the gravity field and an internal heat source.The formulation of the problem is applied in the context of the three-phase-lag model and Green-Naghdi theory without dissipation.The medium is a homogeneous isotropic thermoelastic in the half-space.The exact expressions of the considered variables are obtained by using normal mode analysis.Comparisons are made with the results in the two theories in the absence and presence of the magnetic field as well as the two-temperature parameter.A comparison is also made in the two theories for different values of an internal heat source.

Effects of stretching/shrinking on the thermal performance of a fully wetted convective-radiative longitudinal fin of exponential profile

The present investigation focuses on the thermal performance of a fully wet stretching/shrinking longitudinal fin of exponential profile coated with a mechanism like a conveyer belt.The modeled equation is non-dimensionalized and solved by applying the Runge-Kutta-Fehlberg(RKF)method.The effects of parameters such as the wet parameter,the fin shape parameter,and the stretching/shrinking parameter on the heat transfer and thermal characteristics of the fin are graphically analyzed and discussed.It is inferred that the negative effects of motion and internal heat generation on the fin heat transfer rate can be lessened by setting a shrinking mechanism on the fin surface.The current examination is inclined towards practical applications and is beneficial to the design of fins.

Performance Assessment of Heat Exchangers for Process Heat Integration

Pinch Analysis is an attractive solution for reduction of thermal energy costs in thermo-chemical industries.In this approach,maximum internally recoverable heat is determined and a heat exchange network is designed to meet the recovery targets.The thermal performance of a heat exchanger over its lifetime is however a concern to industries.Thermal performance of a heat exchanger is affected by many factors which include the physical prop-erties of the shell and tube materials,and the chemical properties of the heat transferfluid.In this study,thermal performance of shell and tube heat exchangers designed to meet heat recovery targets in a Pinch Analysis study is simulated.The aim of this paper is to present predictions of thermal performances of shell and tube heat exchan-gers with different heat transferfluids and geometries as they undergo fouling degradation.Engineering approaches based on thermodynamic analysis,heat balance and Kern Design equations,as well as what-if simu-lation modeling are used in this work.Shell and tube heat exchangers were designed to meet internal heat recov-ery targets for three process plants,A,B and C.These targets were published in a separate paper.The effects of degradation of the tubes-due to incremental growth of fouling resistance-on thermal performance of the exchan-ger were simulated using Visual Basic Analysis(VBA).Overall,it was found that growth in fouling reduces ther-mal efficiency of shell and tube heat exchangers with an exponential relationship.An increase of 100%of fouling resistance leads to an average reduction of 0.37%heat transfer.Higher values of logarithmic mean temperature difference(LMTD)and higher ratios of external diameter to internal diameter of the exchanger tubes amplify the effect of fouling growth on thermal performance of the exchangers.The results of this work can be applied in pinch analysis,during design of heat exchangers to meet the internal heat recovery targets,especially in predicting how fouling growth can affect these targets.This can also be useful in helping operators of shell and tube heat exchangers to determine cleaning intervals of the exchangers to avoid heat transfer loss.

The Effect of Internal Heat Acupuncture on the Tolerance Time of Plantar Hot Plate and Pain Threshold of Gastrocnemius Muscle in Rats with Chronic Myofascial Pain Syndrome

Objective:To investigate the effect of internal heat acupuncture on the tolerance time of plantar hot plate and the pain threshold of gastrocnemius in rats with chronic myofascial pain syndrome(MPS).Methods:A total of 80 adult Wistar rats were randomly selected to establish chronic MPS rat models,and randomly divided into four groups:control group,acupuncture group,internal heat acupuncture group A,and internal heat acupuncture group B,with 20 rats in each group.The rats in the control group were not given any treatment,and the rats in the acupuncture group were only given acupuncture treatment.The rats in group A were treated with internal heat acupuncture(needle heating up to 42℃),and the rats in group B were treated with internal heat acupuncture(needle heating up to 44℃).The tolerance time of plantar hot plate,the pain threshold of gastrocnemius muscle and the level of tumor necrosis factor-α(TNF-α)were observed and compared before modeling,1 d before treatment,and 1,7 and 14 d after treatment.Results:There were significant differences in hot plate tolerance time,time and interaction among the four groups(P<0.05),as well as in gastrocnemius tenderness threshold,time and interaction among the four groups(P<0.05),and there were also significant differences in TNF-αlevel among the three groups(P>0.05).There were significant differences in the number of electric shocks,time and interaction among the four groups(P<0.05).Conclusion:In contrast to conventional acupuncture treatment,internal heat acupuncture demonstrates greater efficacy in extending the tolerance duration of hot plate exposure and enhancing the pain threshold of the gastrocnemius muscle in rats afflicted with myofascial pain syndrome.Additionally,it accelerates the amelioration of inflammatory markers and motor function.However,it is important to note that the therapeutic impact of internal heat acupuncture may be influenced by its temperature,with 44℃being the most effective in this research.

Thermodynamic analysis for a third grade fluid through a vertical channel with internal heat generation

This paper makes the thermodynamic analysis in forced convective flow of a third grade fluid through a vertical channel. Due to the reactive nature of the fluid, the effect of internal heat generation is considered and assumed to be a linear function of temperature. The coupled nonlinear dimensionless ordinary differential equations governing the fluid flow are solved by using the Adomian decomposition method（ADM）. The effects of various physical parameters such as third grade material parameter, buoyancy parameter and heat generation parameter on the thermal structure of flow are presented and discussed.

Effect of asymmetrical wall heat flux and wall temperature ratio on mixed convection in a vertical micro-porous-channel with internal heat generation

Mixed convective heat transfer in a vertical parallel plate micro-porous channel with internal heat generation and viscous dissipation,varying wall heat flux ratio and wall tem­perature ratio at the boundaries is investigated using the Darcy-Brinkman model under local thermal non-equilibrium assumption.Numerical solution for both fluid and solid temperature distributions are obtained by applying the finite element method.The effect of pertinent param­eters such as Brinkman number,Rayleigh number,Darcy number,inter-phase heat transfer co­efficient,porosity scaled thermal conductivity ratio and solid internal heat generation are discussed.The results indicate that the Nusselt number increases with the increase in the solid internal heat generation as well as Rayleigh number in both wall heat flux ratio and wall tem­perature ratio boundary conditions.It is observed that with the quantitative increase in viscous dissipation parameter Br,Nusselt number Nu increases in the presence of internal heat gener­ation and it decreases in the absence of internal heat generation,for a specific range of values of wall heat flux ratio and wall temperature ratio.Beyond this range Nu increases with the increase in Dr regardless of internal heat generation.For the cases,constant wall temperature and wall heat flux ratios,good correlation is observed in the results obtained with that of available in the literature.

Thermo-Mechanically Coupled Thermo-Elasto-Visco-Plastic Modeling of Thermo-Induced Shape Memory Polyurethane at Finite Deformation

A series of monotonic tensile experiments of thermo-induced shape memory polyurethane （TSMPU） at different loading rates were carried out to investigate the interaction between the internal heat production and the mechanical deformation. It is shown that the tem- perature variation on the surfaces of the specimens due to the internal heat production affects the mechanical properties of TSMPU remarkably. Then, based on irreversible thermodynamics, the Helmholtz free energy was decomposed into three parts, i.e., the instantaneous elastic free energy, visco-plastic free energy and heat free energy. The total deformation gradient was decomposed into the mechanical and thermal parts, and the mechanical deformation gradient was further divided into the elastic and visco-plastic components. The Hencky＇s logarithmic strain was used in the current configuration. The heat equilibrium equation of internal heat production and heat exchange was derived in accordance with the first and second thermodynamics laws. The temperature of specimens was contributed by the internal heat production and the ambient temperature simultaneously, and a thermo-mechanically coupled thermo-elasto-visco-plastie model was established. The effect of temperature variation of specimens on the mechanical properties of the material was considered in this work. Finally, the capability of the proposed model was validated by comparing the simulated results with the corresponding experimental data of TSMPU.

Numerical solution of micropolar fluid flow via stretchable surface with chemical reaction and melting heat transfer using Keller-Box method

The main theme of this research is to find the numerical results of stagnation point flow of micropolar fluid over a porous stretchable surface due to the physical effects of internal heat generation/absorption,melting heat transfer and chemical reaction via Keller-Box method(KBM).The graphs and tables are depicted and explained for various embedded parameters.The range of melting heat transfer parameter is 0≤M≤3,the range of chemical reaction parameter is 0≤K_(r)≤1 whereas the values of space-temperature dependent heat source/sink parameters lies in-0:4≤Q≤0:4 and-2≤Q*≤2.The upshots of the current problem illustrate that at fluid-solid interface,rate of HMT(heat and mass transfer)declined on escalating the values of stretching parameter.Moreover,as the values of internal heat source/sink parameter increases,heat transfer rate declines at fluid-solid interface.

Natural convective flow of a magneto-micropolar fluid along a vertical plate

This paper presents a numerical study of natural convective flow of an electrically conducting viscous micropolar fluid past a vertical plate. Internal heat generation (IHG) versus without IHG in the medium are discussed in the context of corresponding similarity solutions. Results are presented in terms of velocity, angular velocity, temperature, skin friction in tabular forms, local wall-coupled stress, and Nusselt number. Computations have been accomplished by parametrizing the micropolar, micro-rotation, magnetic field, suction parameters, and the Prandtl number. Several critical issues are addressed at the end of the paper with reference to a previous study by El-Hakiem. The study is relevant to high-temperature electromagnetic materials fabrication systems.

Influence of magneto-thermo radiation on heat transfer of a thin nanofluid film with non-uniform heat source/sink

The objective of the present work is to analyze the flow,heat and mass transfer characteristics in a thin nanofluid film over a heated stretched sheet in the presence of a non-uniform heat source/sink and thermal radiation.Similarity variables are used to transform the partial differential equations into a system of ordinary differential equations.The resulting system of nonlinear ordinary differential equations is then solved numerically by using the Runge-Kutta-Fehlberg integration scheme with a shooting technique.The effects of the unsteadiness parameter,the thermal radiation,the non-uniform heat source/sink parameter on flow and heat transfer fields are analyzed.It is found that an increase in the unsteadiness parameter is to increase the velocity and temperature gradient profiles.However,an increase in the thermal radiation parameter affects the nanoparticle temperature gradient of the nanofluid film but the reversed is true with the concentration gradient.