Temperature Distribution Profile Research Articles

A Short Introduction of Blade Cooling Mechanisms in Old Gas Turbines with the Aim of Proper Distribution of Temperature Profile

Presently, old gas turbines are used in the industry of some developing countries without high tech, which face many problems in the field of thermal efficiency and output power. Typically, turbines operate in the temperature range of 1200 to 1500 degrees Celsius. Many studies have been done to increase the efficiency of such systems. The results show that this increase in temperature at the inlet of the gas turbine has negative consequences, such as increasing the thermal load of the turbine blades and thus reducing the lifetime of the blades. On the other hand, a damaged blade can cause serious damage to other blades as well as the main shaft and other parts in various ways and sometimes lead to complete failure of the turbine. Therefore, it is reasonable to consider cost reduction considerations, including maintenance. Hence, due to the limitation of thermal stresses for the continuous operation of gas turbine blades, the distribution of heat transferred to them must be controlled. In this regard, the presence of blade cooling mechanisms is necessary for its safe operation, because the operating temperature of the gas turbine is much higher than the allowable temperature of the blades. In addition to cooling the blades, cooling the shell and inlet nozzle of gas turbines is also extremely important. But since the blades are exposed to high-level stress and tension for a long time, their cooling is more important and sensitive. For this reason, in the present article, the authors tried to provide a short introduction to the efficient mechanisms in cooling the blades related to the old systems, whose effect is noticeable on increasing the lifetime of the blades.

Role of suction/injection on electromagnetohydrodynamics natural convection flow in a porous microchannel with electroosmotic effect

This paper examined the role of suction/injection on time-dependent electromagnetohydrodynamics (EMHD) natural (free) convection flow in a vertical microchannel with electroosmotic effect. With the aid of Laplace transformation method, the governing energy and momentum equations are converted from partial differential equation (PDE) into ordinary differential equation (ODE) to obtain fluid temperature and velocity in Laplace domain. The semi-analytical solutions of the velocity profile and temperature distribution have been derived using the Riemann sum approximation. After which a MATLAB program was written to study the effects of Prandlt number Pr, Hartmann number Ha, electric field strength on x and z directions (Ex and Sz) and Grashof number Gr in fluid velocity, temperature, skin-friction and mass flow rate in terms of line graphs. Result shows the role of suction/injection parameter alters the temperature distribution and velocity profile, so also how effective the governing parameters contribute to the flow formation. .

Magneto-convective hybrid nanofluid slip flow over a moving inclined thin needle in a Darcy-Forchheimer porous medium with viscous dissipation

PurposeThe purpose of this study is to provide that porous media and viscous dissipation are crucial considerations when working with hybrid nanofluids in various applications.Recent years have witnessed significant progress in optimizing these fluids for enhanced heat transfer within porous (Darcy–Forchheimer) structures, offering promising solutions for various industries seeking improved thermalmanagement and energy efficiency.Design/methodology/approachThe first step is to transform the original partial differential equations into a system of first-order ordinary differential equations (ODEs). The fourth-order Runge–Kutta method is chosen for its accuracy in solving ODEs. The present study investigates the free convective boundary layer flow of hybrid nanofluids over a moving thin inclined needle with the slip flow brought about by inclined Lorentz force and Darcy–Forchheimer porous matrix, viscous dissipation.FindingsIt is found that slip conditions (velocity and Thermal) exist for a range of the natural convection boundary layer flow. In the hybrid nanofluid flow, which consists of Al2O3 and Fe3O4 are nanoparticles, H2O − C2H6O2 (50:50) are considered as the base fluid. The consequence of the governing parameter on the momentum and temperature profile distribution is graphically depicted. The range of the variables is 1 ≤ M ≤ 4, 1 ≤ d ≤ 2.5, 1 ≤ δ ≤ 4, 1 ≤ Fr ≤ 7, 1 ≤ Kr ≤ 7 and 0.5≤λ ≤ 3.5. The Nusselt number and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in Table 4. These analyses elucidate that upsurges in the value of the Fr noticeably diminish the momentum and temperature. It is investigated to see if the contemporary results are in outstanding promise with the outcomes reported in earlier works.Practical implicationsThe results can be very helpful to improve the energy efficiency of thermal systems.Social implicationsThe hybrid nanofluids in heat transfer have the potential to improve the energy efficiency and performance of a wide range of systems.Originality/valueThis study proposes that in the combined effects of hybrid nanofluid properties, the inclined Lorentz force, the Darcy–Forchheimer model for porous media and viscous dissipation on the boundary layer flow of a conducting fluid over a moving thin inclined needle. Assessing the potential practical applications of the hybrid nanofluids in inclined needles, this could involve areas such as biomedical engineering, drug delivery systems or microfluidic devices. In future should explore the benefits and limitations of using hybrid nanofluids in these applications.

Laser-Induced Temperature Changes on the Outer Surface of Titanium Dental Implants: An In Vitro Study.

To measure the surface temperature distribution after using a CO2 laser to heat titanium dental implants via different power settings, application intervals, and irradiation times. A total of 10 tissue-level titanium implants (Screw-Line Promote Plus, Camlog; 4.3 × 11 mm) were placed (EpoFix, Struers) and irradiated with a CO2 laser (Denta 2, Lutronic) with a wavelength of 10.6 μm at power levels of 4 watts (Group 1), 6 watts (Group 2), 8 watts (Group 3), and 10 watts (Group 4). A continuous beam mode (setting I) and noncontinuous beam modes with 5-second (setting II) and 10-second (setting III) pause intervals were used. For each setting, a total irradiation time of 50 seconds was used and repeated 10 times. The temperature was measured using external thermocouple (Testo) in contact with the implant surface at the implant shoulder, middle, and apex. A linear regression model was used to analyze the data (P = .05). Setting I demonstrated the most rapid increase in implant surface temperature in all three test sites as well as the greatest total temperature at 50 seconds of irradiation time. The greater the pause interval (settings II and III) during the 50 seconds of irradiation, the lower the rate of temperature increase as well as the total temperature in all three test sites and with all power levels. The average temperature difference between the apex and shoulder site was significant for setting III for all groups, but not for any groups in settings I and II. Heating the internal aspect of an implant with a CO2 laser produces different temperature distribution profiles depending on the laser power level and the application interval. Laser-beam irradiation leads to a temperature gradient, which is greatest at the implant apex and smallest at the implant shoulder.

Mixed convection of shear-thinning hybrid nanofluid flow across a radiative unsteady cone with suction and slip effect

The present study examines the intricate dynamics of flow velocities, temperature distribution, and concentration profiles within Casson hybrid nanofluids as they traverse an unsteady vertical rotating cone, accounting for suction velocity and slip effects. The investigation dissects shear stress rates and thermal and mass transfer rates, leveraging the computational power of MATLAB's bvp4c method to tackle the problem's high non-linearity. The research extends to explore the interplay of magnetic parameters, radiation parameters, thermophoresis, Brownian motion, and chemical reactions in the context of Casson hybrid nanofluid flow over an unsteady vertical rotating cone. The incorporation of velocity slip effects and suction velocity emerges as a pivotal catalyst, elevating the rates of heat and mass transfer. Notably, the findings reveal a substantial enhancement in tangential and azimuthal skin friction by 52 % and 34 %, respectively, when transitioning from Casson nanofluid to Casson hybrid nanofluid. Most strikingly, the rate of heat transfer experiences a remarkable surge of 125 % when Casson hybrid nanofluid supplants Casson nanofluid. This research opens up exciting possibilities for improving heat and mass transfer in various industrial applications, making it a compelling contribution to the field of fluid dynamics and nanofluid research.

Analytical assessment of heat transfer due to Williamson hybrid nanofluid (MoS2 + ZnO) with engine oil base material due to stretched sheet

The efficiency of fuel consumptions and improved performances is real challenge in the vehicle engines. Recent advances in thermal engineering suggested various tools to improve the capacitance of engine oil for which the interaction of nanoparticles is more dynamical. The aim of current research is to enhance the thermal aspects of engine oil with suspension of Williamson hybrid nanofluid. The hybrid nanofluid is the suspension of molybdenum disulfide MoS2 and zinc oxide ZnO. In order to increase the heating capability of system, external heat source and viscous dissipation features are contributed. The flow analysis is based on moving surface contains porous medium. After modelling the problem, the analytical outcomes of attributed with variational iteration method (VIM). The computational simulations are performed with help of Lagrange Multiplier technique. The impact of numerous physical parameters on skin fraction, Nusselt numbers, temperature distribution and velocity profile is exhibited.

Prediction model for properties of hot-rolled steel strip: An ICME approach

The Integrated Computational Materials Engineering (ICME) approach is implemented to develop an integrated model for the processing of steel at a hot strip mill. The effect of temperature, deformation, and subsequent cooling rate on microstructure and its associated properties of the steel are mapped using analytical, numerical as well as machine learning approaches, all applied in tandem. The modeling approaches include a rigid visco-plastic approach for the flow formulation, finite volume method to calculate temperature distribution profile, artificial neural network (ANN) modeling for predicting CCT diagram, and Mecking–Kock model along with stress mixing law for the structure–property correlation. The composite model for mapping the final microstructure and microstructure-dependent properties of the steel, which depends on the composition, and various parameters of the hot strip mill is validated through a comparison of predicted values with the published results. The work shows that the hybridization of constitutive equations with the data-driven approach in ICME can successfully model a complex system like the hot strip mill.

Numerical modeling of the carbonization of polyimide fibers in a cylindrical furnace

Carbon fiber is widely used as a reinforcing material in polymer composite such as carbon fiber reinforced plastic (CFRP) due to its high specific strength, elastic modulus and lightweight. The majority of the industrial carbon fiber is produced from synthetic precursor polymer such as polyacrylonitrile (PAN), pitch and polyimide. While relatively many studies have been published for the carbonization of PAN, little studies have been found on the heat transfer during carbonization of polyimide precursors. In this study, we numerically analyzed the carbonization process of a polyimide (PI) precursor for carbon fibers in a lab-scale cylindrical furnace. Gas flow, temperature distribution and concentration profiles including the off-gases from the precursor fibers were included in the analyses. First, we established mathematical models for the off-gases behavior from the precursor fibers. The models were incorporated into computational fluid dynamics in order to find behavior of the mixture gas of the working nitrogen gas and the off-gases. And then, numerical simulation results using the model were obtained and compared to the experimental results to verify the model. Finally, we evaluated the application scalability of the established numerical model through changes in wall temperature and precursor fiber moving speed. The results showed that the model can be used to study the PI carbonization process in the industrial size carbonization furnace.

Numerical simulation of effect of hybrid nanofluid on heat transfer and flow of the Newtonian pulsatile blood through 3D occluded artery: Silver and gold nanoparticles

The study of blood flow in obstructed arteries is a significant focus in computational fluid dynamics, particularly in the field of biomedicine. The primary objective of this research is to investigate the impact of pulsating blood velocity on heat transfer within biological systems, with a specific focus on blood flow in obstructed arteries. To achieve this goal, a comprehensive 3D model representing a straight, constricted blood vessel has been developed. This model incorporates periodic, unsteady, Newtonian blood flow along with the presence of gold and silver nanoparticles. Leveraging the Finite Element Method (FEM), the Navier-Stokes and energy equations have been rigorously solved. Through the investigation, it is aim to shed light on how alterations in the pulsation rate and the volume fraction of nanoparticles influence both temperature distribution and velocity profiles within the system. The present study findings unequivocally highlight that the behavior of pulsatile nanofluid flow significantly impacts the velocity field and heat transfer performance. However, it is imperative to note that the extent of this influence varies depending on the specific volume fractions involved. Specifically, higher volume fractions of nanofluids correlate with elevated velocities at the center of the vessel and decreased velocities near the vessel walls. This pattern also extends to the temperature distribution and heat flux within the vessel, further underscoring the paramount importance of pulsatile flow dynamics in biomedicine and computational fluid dynamics research. Besides, results revealed that the presence of occlusion significantly affects the heat transfer and fluid flow.

Multi-physics coupling analysis of test heat pipe reactor KRUSTY based on MOOSE framework

The heat pipe reactor utilizes heat pipes for passive heat transfer, eliminating the need for any moving parts. This feature significantly enhances its safety characteristics. Given the intricate nature of the heat pipe reactor system, a comprehensive multi-physics coupling simulation is necessary to study its safety features. In this study, a high-fidelity multi-physics coupling analysis incorporating a neutronic-thermal–mechanical-heat pipe coupling model is conducted. The work is based on the multi-physics coupling framework MOOSE, which integrates the Monte Carlo code OpenMC for neutronic analysis and built-in modules for 3-dimensional thermal–mechanical analysis. Furthermore, a heat pipe simulation method called the Thermal Resistance Grid Method is implemented within the MOOSE framework and employed in the multi-physics coupling analysis. To facilitate transient analysis, the Point Kinetics method is also integrated into the MOOSE framework to account for the time-varying power factor during reactor transients. The various modules and physical fields are coupled together using either loose or tight coupling strategies. These coupling strategies are applied to assess a test heat pipe reactor known as KRUSTY. Steady-state simulations are conducted for both normal operation and single heat pipe failure conditions, enabling the calculation of fission power distribution, temperature distribution, stress and strain profiles, as well as power and temperature redistribution following a heat pipe failure. Moreover, a load-following transient of KRUSTY is simulated, demonstrating its capability for load following without reactivity control. The aforementioned calculations validate the feasibility of the coupling framework utilized in this study and highlight its ability to accurately capture local phenomena within the reactor core.

Impact on Casson Nanofluid Flow Across an Inclined, Slanted Surface by Radiation, Energy and Mass Transfer

Casson nanofluid flow across a porous, slanted surface is investigated. In addition to the impact of a heat source, thermal energy, and a chemical reaction also are considered. Applying similarity transformations, the controlling nonlinear PDEs are converted to ODEs. To resolve the ordinary differential equations (ODEs), we used the universal numerical differential equation solver Wolfram Language function NDSolve. The distributions under heat source are affected by chemical processes and other variables are explored. While liquid velocity reduced due to inclination and the Casson factor, mass and energy transit rates rose. The findings are represented graphically and are consistent with past research. The findings would provide valuable insights into the flow patterns, temperature distribution, and concentration profiles within the system. This information can be crucial for designing and optimizing heat transfer systems, energy-efficient processes, and catalytic reactors involving Casson nanofluids and porous media.

EFEK LAJU PEMANASAN (HEATING RATE) TERHADAP DISTRIBUSI TEMPERATUR DAN KINERJA MODUL THERMOELECTRIC GENERATOR SP1848 SA

Thermoelectric Generator (TEG) is an energy conversion technology that converts heat energy into electrical. There are several factors that affect the performance of TEG, one of which is the heat source. This research will investigate the use of waste heat by varying the heating rate on the performance of TEG in generating electricity and the temperature distribution profile through experimental studies on a laboratory scale. The heating plate is used to heat the hot surface of the TEG. There are three variations of the heating rate used, namely: Low (0.355°C/min), Middle (0.933 °C/min) and High (1.558 °C/min). Temperature measurements were carried out on the hot surface (Th), the cold surface (Tc) of the TEG module, and the ambient temperature (Ta) using Arduino temperature data logger. Meanwhile, to measure the electrical output in the form of voltage (V) generated by the TEG module, using the Arduino voltage data logger. The results show when the heating rate used is high (high heating rate) then the average electrical output of the TEG module produces a voltage of 5.34V. The heating rate on the hot surface of the TEG module will affect the difference in surface temperature and the performance of the TEG module in generating electricity.

Magnetohydrodynamic micropolar slip flow due to an exponentially stretching sheet with chemical reaction and nonuniform heat generation

AbstractThe main focus of the current study is to examine the impact of melting heat transfer and chemical reaction on magnetohydrodynamic micropolar fluid flow over a sheet that is exponentially stretching and immersed in a porous medium. A nonuniform heat source is placed within this flow system. Other impacts like slip phenomena and thermal radiation are also taken into consideration. The governing partial differential equations are converted to a system of ordinary differential equations (ODEs) via similarity transformation and we also get the corresponding necessary boundary conditions. These nonlinear ODEs are resolved with the help of shooting technique and an Runge‐Kutta fourth order (RK‐4) iterative strategy. Also, we solve this problem using the Bvp4c approach for validating the results of the RK‐4 method. Both outcomes are consistent with previously published data. With the help of tables and graphs, we examine the influence of multiple physical parameters on velocity, thermal, microrotation, concentration, Nusselt number, Sherwood number, coefficient of skin friction, and wall couple stress. We see that the temperature distribution and velocity profiles decrease when the melting parameter increases. The temperature profile boosts when the heat source parameter is increased.

Amplitude and oscillating assessment of thermal and magnetic boundary layer flow across circular heated cylinder with heat source/sink

The effects of heat source/sink and magnetohydrodynamics on the oscillatory and periodic quantities of heat transfer and current density characteristics of viscous fluid along the magnetized and heated circular cylinder has been investigated. The governing mathematical model in terms of partial differential equations is converted into dimensionless form. The dimensionless model is again converted into steady, real and imaginary part for oscillating results. The steady, real and imaginary part is transformed into primitive form for smooth algorithm with the help of Primitive Variable Formulation (PVF). The primitive equations are reduced into system of algebraic equations by using Finite Difference Method (FDM). The heat source/sink parameter δ, the magnetic force number ξ, the buoyancy parameter λ, magneto-Prandtl factor γ, and remaining secured factors are utilized to determine computational findings of unknown quantities. Graphs are displayed for velocity, temperature distribution and magnetic profile for all pertinent parameters by FORTRAN and Teplot 360 software. The main novelty of current work is to evaluate oscillatory and periodic quantities of heat transfer and current density by using the steady solutions. It was found that prominent results in temperature distribution are deduced at each angle with the heat source effects. It was expected physically because the heat source is used as a sporting agent to compute heat transfer performance in electrically conducting fluid. The significant amplitude of oscillation in heat transfer and current density is evaluated around every position of circular cylinder. The numerical results of skin friction are compared with existing literature with excellent agreement.

A study under the impact of Soret and Dufour effects on MHD stagnation point flow and heat transfer towards a stretching sheet

This paper signifies the consequence of the thermal diffusion (Soret) and diffusion-Thermo (Dufour) effect on MHD stagnation point flow and transportation of thermal energy near a stretching plate. However, the inclusion of thermal radiation, heat generation/absorption, and chemical reaction enriches the profiles significantly. By using similarity transformation, the set of leading equations is altered into a set of dimensionless ordinary differential equations. After that, the aim is to convert boundary layer equations into dimensionless ones so that the set of converting equations is computed by using bvp4c solver on MATLAB software. The governing nonlinear equations were resolved with Runge–Kutta fourth-order technique numerically. The significance of radiation, magnetic field, suction, Schmidt number, velocity ratio parameter, heat absorption coefficient, permeability, thermo-diffusion number, diffusion-thermo number on momentum gradient, energy gradient and concentration gradient distribution is analyzed. The parameters, diffusion-thermo number Du and thermo-diffusion number Sr have opposite behaviors on both temperature and concentration fields. Here, also, it is observed that the heat sink parameter has a noticeable influence on the fluid temperature distribution profile.

Analysis of assisting and opposing flows of the Eyring-Powell fluid on the wall jet nanoparticles with significant impacts of irregular heat source/sink

Nanofluids are employed in a variety of human endeavors, such as engineering tools in chemical and power engineering, electronics, medicine, and other areas. Thus, this article investigates the wall jet flow (WJF) and heat transfer (HT) by incorporating the Eyring-Powell nanofluid with a significant consequence of erratic heat source/sink and buoyancy. The leading equations are converted by similarity variables and then obtained numerical solutions by the bvp4c technique. The influences of physical influential parameters on the dimensionless velocity and dimensionless temperature distribution profiles are discussed to predict the behavior of the fluid flow and heat transfer. Also, the heat transfer and friction factor were elaborated with the aid of tables for dimensionless emerging parameters. Moreover, the current results are compared with published results in a limiting case to show the accuracy of the present method. Finally, the current study informs us that the relevant parameters have had a considerable impact on the profiles of the boundary layer.

Comparison of the corrugated steel web composite box-girder and traditional girders regarding temperature field under solar radiation

The corrugated web composite box-girder (CWCB) is a novel structural form and has been widely adopted in bridge engineering due to its excellent mechanical properties and construction convenience. However, researches on the temperature field in CWCB is very limited, which may augment the risk of concrete cracking and steel web bucking and deteriorate the durability of bridge structures. This paper thereby experimentally investigates the time-varying and spatial temperature distribution features of CWCB based on a long-term temperature monitoring system. The experimental results indicate that the temperature field in CWCB is non-uniformly distributed and the vertical and horizontal temperature differences can reach up to 13.4 ℃ and 19.1 ℃, respectively. Meanwhile, the observed temperature distribution profile of the experimental CWCB is varying with seasons owing to the different exposure to solar radiation. Then, a refined numerical thermal simulation approach is developed and its reliability and accuracy have been validated by the experimental temperature data of three types of box-girders, i.e., CWCB, ordinary composite box-girder (OCB), and conventional concrete box-girder (CCB). Based on the validated numerical approach, the temperature fields of three full-sized box-girders are therewith compared and the results demonstrate that the temperature field in CWCB is much more complicated than the traditional box-girders. Besides, the obtained cross-sectional temperature differences of CWCB are significantly larger than that of the traditional box-girders. Finally, two temperature profiles have been proposed to characterize the thermal actions in CWCB, which are composed of parabolas and polylines. The outcome of this study can provide a useful tool for analyzing the temperature field and calculating the design thermal load of CWCB.

Computational framework of cobalt ferrite and silver-based hybrid nanofluid over a rotating disk and cone: a comparative study

The dominant characteristics of hybrid nanofluids, including rapid heat transfer rates, superior electrical and thermal conductivity, and low cost, have effectively piqued the interest of global researchers. The current study will look at the impacts of a silver and cobalt ferrite-based hybrid nanofluid with MHD between a revolving disk and cone. The collection of partial differentiable equations is converted into a set of ODEs via similarity transformations. We used the Homotopy analysis approach from the BVPh 2.0 package to solve the ordinary differential equations. The volume proportion of nanoparticles increases and the temperature distribution profile also increased. It is more efficient for metallurgical, medicinal, and electrical applications. Furthermore, the antibacterial capabilities of silver nanoparticles might be used to restrict the growth of bacteria. A circulating disc with a stationary cone has been identified to provide the optimal cooling of the cone disc device while maintaining the outer edge temperature constant. This study's findings might be useful in materials science and engineering. The usage of hybrid nanofluid in heat transfer and heat pumps, coolants in manufacturing and production, producing cooling, refrigerators, solar thermal collectors, and heating, air conditioning, and climate control applications are only a few examples.

NOX EMISSION ON RECIPROCAL FILTRATION COMBUSTION OF BIOGAS: A CASE STUDY

Filtration combustion is an effective technique for dealing with low-calorific value fuels, such as derivative fuels from biomass, and simultaneously reducing pollutant emissions. In this study, combustion of biogas (22% of CO2) was investigated theoretically and experimentally by utilizing a reciprocal flow porous burner with heat exchangers inserted in the porous medium. Combustion of lean biogas-air mixtures is stabilized in a naturally transient process, in which a lean equivalence ratio range (0.1 ≤ Φ ≤ 0.9) and gas flow velocities of 0.2 and 0.3 m/s were employed, periodically switching gas flow direction. Reciprocal flow combustion has been compared with unidirectional combustion, using technical methane as reference gas. In this context, predicted temperature profiles inside the burner, as well as experimental results, have shown that the reciprocating system plays an important role in the combustion process, significantly improving flammability limits, efficiency, and emissions. As result, trapezoidal temperature distribution profiles have been obtained with peaks between 1200 and 1600 K, reaching high efficiency up to 90% and ultra-low emission of nitrogen oxides (≤ 2ppm).

MHD Stagnation-Point Flow and Heat Transfer in a Micropolar Fluid over an Exponentially Vertical Sheet

This paper examines the magneto hydrodynamic (MHD), stagnation-point flow and heat transfer caused by an exponentially stretching/shrinking vertical sheet and the presence of mixed convection (buoyancy effect) in a micropolar fluid. A set of variables is employed to transform the system of partial differential equations (PDEs) to ordinary differential equations (ODEs). The ODEs are then numerically solved in MATLAB software using BVP4c. There are a lot of agreements when compared to previous findings. The impacts of different parameters, such as micropolar, magnetic, mixed convection, radiation, temperature, and stretching/shrinking parameters are displayed graphically. It is found that contradictory phenomena between Micropolar and mixed convection for fluid velocity, angular velocity and temperature distribution profiles. The velocity profile at the vertical plate increases due to the increasing buoyancy, magnetic and radiation parameters. The particle rotation occurs in two phenomena for buoyancy and magnetic parameters and it is reversible for micropolar. The temperature of the fluid decreases with buoyancy and magnetic parameters.