The main purpose of this study is to investigate numerically the thermal performance of a parabolic trough solar collector’s absorber tube that contains a novel kind of inserts with the objective to improve the heat transfer between the heat transfer fluid and the absorber tube. In the first part of this paper, the diameter and the length of the cylindrical inserts are investigated based on Finite Volume Method and Monte Carlo Ray Tracing method for Reynolds number ranges from 2.36∙10^4 to 7.09∙10^4. In the second part, the eccentricity of the cylindrical inserts is investigated under the same operating conditions. The Therminol ®VP1 is the HTF that used in this investigation intermediate fluid. The numerical simulation indicates that the perturbators enhance the thermal behavior of receiver and reduces the absorber tube’s temperature difference.

The impacts of vertical throughflow, rotation, cross-diffusion, and vertical heterogeneous permeability on the double-diffusive convection in a finite rotating vertical porous cylinder have been studied. The fluid in the cylinder is warmed and salted from beneath, and its top and lower walls are taken to be isothermal, isosolutal and permeable. In the model formulation, the Brinkman model was adopted, coupled with the Boussinesq approximation. The normal mode technique is used to perform linear stability analysis and single term Galerkin technique is employed to solve the eigenvalue problem. Further, the influence of vertical heterogeneity, vertical throughflow, thermal and solute Rayleigh, Taylor, and the Soret and Dufour numbers on the fluid system instability has been investigated. We found, among other results, that vertical heterogeneity may either stabilize or destabilize the fluid system. The Dufour number delays both the stationary and oscillatory convection onsets. The positive Soret number is found to have a stabilizing effect on the stationary convection case, with a destabilizing effect on the oscillatory convection case.

The main focus of the current study is to examine the impact of melting heat transfer and chemical reactions on MHD micropolar fluid flow over a sheet that is exponentially stretching and immersed in a porous medium in which the source of heat is not uniform. Also taken into consideration are slip phenomena and thermal radiation. The governing PDEs are converted to a system of ODEs via similarity transformation and the necessary boundary conditions. These nonlinear ODEs are resolved with the help of shooting techniques and an RK-4 iterative strategy. Also, solved 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 profile, microrotation, concentration profiles, 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 boost when the heat source parameter is increased.

This study's primary objective is to demonstrate how diffusion-thermo and thermal diffusion influence of peristaltic flow processes with slip boundaries when joule heating happens from the interior. Several operational factors and their impacts on the system were analysed, along with the corresponding graphs. As slip parameters rise, the axial pressure gradient fluid flow tends to drop. The pressure rate is demonstrated to drop in the backward and peristaltic pumping regions as the quantity of the second order slide parameter rises, whereas it rises in the co-pump zone. As slip parameters rise, fluid temperature and concentration tend to drop. Changes in the thermal diffusion and thermo diffusion factors cause changes in the fluid's temperature and concentration. The Nusselts number can be increased by increasing the Prandtl number, the thermo-diffusion constraint, the dufour number, and the Schmidt number. However, this will result in fewer Sherwood number.

Slag entrapment from metal-slag interface during continuous casting operation has been a major area of concern for steelmakers globally. The presence of inactive regions in the upper region of the mold poses another challenge. Proper flow behavior of the molten metal coming out of the nozzle in the mold is required to overcome these challenges. Nozzle design greatly affects the flow pattern of the molten steel inside the mold. The present investigation is an attempt to study the flow and solidification behavior in a slab caster mold with the use of a novel designed hexa-furcated nozzle (HFN) using numerical investigation results. The casting speed and submerged entry nozzle (SEN) depth are varied to study the effect of these parameters on minimizing the inactive zones in the mold and the steel/slag interface fluctuations. The results show that the interface fluctuation increases at higher casting speed and lower SEN depth. The RTD analysis is also performed for different cases to investigate the flow behavior. The validation of the fluid flow and RTD curve inside the computational domain is carried out with the use of physical modeling.

This work investigates the effect of Joule heating and viscous dissipation due to electric double layer (EDL) and electroosmotic effect on steady fully developed electromagnetohydrodynamic flow in a porous microchannel. Dimensionless formulations of the Poisson-Boltzmann, momentum, and energy equations are derived for the electric potential, velocity profile and temperature distribution in the microchannel. Exact solutions for the temperature distributions and velocity profile were obtained using the method of undeterminate coefficients. The Debye-Hückel linearization is used to get exact solution for the electric potential. The results showed that Brinkmann number ( Br ) , Joule heating parameter ( J ) , Debye-Hückel parameter ( Κ ) , Hartmann number ( M ) , electric field ( E z ) and suction/injection parameter ( S ) have a substantial impact on flow formation and heat transfer. Using MATLAB software, graphical simulations are provided in order to deliver a greater understanding of the influence of relevant parameters on the results achieved.

The current study focuses on the thermal distribution in the boundary layer of a wedge with a variable surface temperature. The governing equations of MHD flow for variable wall temperature conditions can be converted to ODE by using similarity solutions, and the Hartmann number (Ha) from 1 to 3 can be solved via the colocation method. This method’s results are compared to those of the numerical method, and it is then evaluated and validated. As the angle or Ha increases, the width of the hydrodynamic boundary layer decreases, and the slope of the boundary layer increases, increasing the coefficient of friction on the surface. The results are obtained for variable wall temperature (n), Prandtl number (Pr) and Eckert number (Ec), where they are 0.5≤n≤1.5, 0.5≤Pr≤5, and 0.001≤Ec≤0.002, and at a certain angle. It is observed that when Ha, Pr, and n increase, the thermal boundary layer grows faster than before; thus, thickness decreases and the Nusselt number (Nu) rises; however, as the Ec adds, the Nu decreases on the wall.

During the Stelmor air-cooling process, the temperature distribution has a significant impact on the wire loops’ final mechanical properties. The temperature distribution during air-cooling process is accurately solved by establishing three-dimensional model and numerical simulation. The heat transfer coefficient at the high dense region is much smaller than that of wire loops at the low dense region, and changes periodically over time, according to a Computational Fluid Dynamics (CFD) simulation method. It is also found that the heat transfer coefficient on the cross section of the wire loop is very different, with a difference of 70-100 Wm-2K-1. Finally, the finite difference method is used to calculate the mathematical model of the temperature distribution during the Stelmor air-cooling process. Comparing the results with the measurement data, the simulation results and measurement data match up well.

The quest for augmenting dropwise condensation heat transfer performance has been the driving force behind the exploration of innovative techniques and approaches to fulfil the desired objective. Recent literature in condensation heat transfer unveils that dropwise condensation heat transfer improvements from Slippery Liquid Infused Porous Surfaces (SLIPSs) was central to the study of several researchers because these surfaces have shown excellent droplet mobility due to extremely low adhesion between the condensing liquid and the lubricant infused surface, thereby, promote dropwise condensation. As part of supplementing current research on SLIPSs, for the first time, the present study explores the potential of a semi-solid lubricant impregnated porous surface in enhancing the condensation heat transfer performance of a vertical condenser tube. The results of experiments conducted over a wide range of subcooling (5°C ≤ ΔT ≤ 65°C) in a saturated steam environment signify that Copper tubes with semi-solid lubricant impregnated porous surfaces are potential candidates for enhancing dropwise condensation heat transfer coefficient when compared to an untreated vertical Copper condenser tube. The highest enhancement is found to be 280% at a subcooling of 40°C. Also, the semi-solid lubricant impregnated porous surfaces are proficient in sustaining dropwise condensation for a time period of 72 hours without any degradation in the heat transfer performance. The method devised here for fabricating the semi-solid lubricant impregnated surfaces is simple, less expensive, and less time-consuming compared to the techniques reported earlier for fabricating the SLIPSs. Additionally, in this work an approach based on numerical optimization by a stochastic global optimization technique, namely, Genetic Algorithm, is proposed to retrieve the coefficients and the exponent in the mathematical expression of overall resistance, which in turn is used to compute the tube-side dropwise convection heat transfer coefficient.

The heat transfer in power-law fluids across three corrugated circular cylinders placed in triangular pitch arrangement is studied computationally in a confined channel. Continuity, momentum and energy balance equations were solved using ANSYS FLUENT (Version 18.0). The flow is assumed to be steady, incompressible, 2D and laminar. A square domain of side 300 Dh is selected after detailed domain study. An optimized grid with 98187 cells is used in the study. The convergence criteria of 10 -7 for the continuity, x-momentum and y-momentum balances and 10 -12 for energy equation were used. Constant density and non-Newtonian power-law viscosity modules were used. Diffusive term is discretized using central difference scheme. Convective terms are discretized using Second Order Upwind (SOU) scheme. Pressure-velocity coupling between continuity and momentum equations was implemented using the SIMPLE (Semi-Implicit Method for Pressure Linked Equation) scheme. Streamlines show wake development behind the cylinders, which is much dominant at large ReN and n. Isotherm contours are cramped at higher values of ReN and PrN, implying higher heat transfer. Global parameters like Cd and Nu are computed for the wide ranges of controlling dimensionless parameters, such as power-law index (0.3 ≤ n ≤ 1.5), Reynolds (0.1 ≤ ReN ≤ 40) and Prandtl numbers (0.72 ≤ PrN ≤ 500). The NuLocal plot attains a pitch near corrugation of surface due to abrupt change in velocity and temperature gradients. Nu increases with ReN and/or PrN and decreases with n under otherwise identical situations. Nu is correlated with pertinent parameters, namely, ReN , PrN and n.

This topic has been studied using constant interior and exterior finishing materials (Thermostone, 200 mm thick (A), fired clay bricks, 240 mm thick (B), hollow concrete blocks, 200 mm thick (C), solid concrete blocks, 140 mm thick (D), and limestone, 200 mm thick (E)) due to the availability of many different types of building materials in Iraq and the lack of control over the use of the best. to demonstrate how each of these materials affects a building’s insulation to deliver the appropriate levels of comfort and achieve the greatest possible reduction in the electrical energy needed for air conditioning. A unique chamber was created for performing the actual trials on such walls in their natural environment, which was the climate of the city of Baghdad (zip code 10016,33 ºN latitude, 44 ° E longitude). And a unique room was created for performing real-world tests on those walls, either in their current state of operation or with the addition of thermal insulation (60 mm thick microfiber glass insulation materials). The values for electricity consumption are 199,138,121,101,92 kW/m2 without the insulator, but when the insulator is used, the values become 54,92,63,100,58 kw/m2 for the models Case-C1, Case-E1, Case-B1, Case-D1, and Case-A1. respectively, the percentage of the reduction in electrical energy consumed by the room’s air conditioner ranges from 25–60%, depending on the model compared to the conventional model, and the difference in savings is only 35%. The amount of savings in the electrical energy consumed by the air-conditioning unit used (to provide standard thermal conditions inside the building) will decrease when the insulator is incorporated into the structural components because the savings difference will be equal to 15% only when changing the quality of the wall used (described in the study) compared to the traditional method.

This investigates the fluid flow, as well as the heat and mass transfer phenomena occurring within a vertical channel housing two immiscible fluids. It focuses particularly on slip effects, encompassing no slip, velocity slip, thermal slip, and multiple slips, each being applied with appropriate boundary conditions. The analysis thoroughly examines crucial characteristics such as variations in thermal conductivity and viscosity. By employing a sixth-order Runge-Kutta numerical method implemented via Mathematica, the study achieves precise solutions for complex scenarios. The extensive findings elucidate the intricate interactions among different slip mechanisms and relevant parameters, providing valuable insights for both theoretical comprehension and practical application in engineering contexts. Furthermore, this research offers significant insights into the dynamics of fluid flow, heat, and mass transfer under various slip effects. Noticeable variations in these slip effects are observed and visually represented. Engineering parameters such as Nusselt number, shear stress, and Sherwood number are meticulously calculated and analyzed using bar charts, offering insights into their impact and behavior.

Regulation of the thermal performance of electrical components is a key aspect. Phase-change materials can be incorporated into a fin heat sink (FHS) to enhance thermal management by maintaining a stable temperature. Three types (square, triangular, and circular) of aluminum FHSs of different configurations are investigated numerically in this paper. Studies are conducted with and without PCMs. Paraffin wax, stearic acid, and polyethylene glycol are used as PCMs to find the best combinations for thermal cooling and to determine the impact of using PCMs in the heat sinks. The results obtained show that, by adding PCMs, temperature rise can be delayed, and polyethylene glycol performs better than other PCMs. Moreover, the square fin heat sink increases the thermal regulation period. As the height of the fins increases from 10 mm to 16 mm, thermal efficiency increases. Hence, the findings of this paper would be beneficial for effective thermal management in the electronic industry.

The paper focuses on the simulation and testing of a hybrid solid desiccant vapor compression air conditioning system under different hot-humid climates. The simulation is carried out by a BLUEJ programming framework. Air at the lowest achievable air temperatures from a solid desiccant cooling system is supplied to a standard vapor compression air conditioning system. The cooling capacities of the hybrid system under three modes indicating different supply air conditions to the cabin, are reported in the paper. From the performance study, it is inferred that the hybrid system provides significant energy savings compared to a standard air conditioner, especially in hot-humid ambient conditions. The solid desiccant cooling system thus establishes itself as an effective pre-cooler unit to a standard vapor compression air conditioning system.

The chief objective of the present investigation is to study experimentally the hydraulic and thermal performance of a corrugated tube with copper foam cylindrical inserts (MFCI) containing a new types of inserts with the purpose to improve the procedure of heat transfer, which gives an elevated thermal enhancement factor (PEF) more than that of smooth tube beneath the similar operating circumstances. Also, in this paper, the study of the effect on the number of cylindrical insert was made from metal foam (10 PPI and porosity 0.9) on the Nusselt no. and Nusselt no. ratio as a double heat exchanger furnished with the suggested MFCI with various values of Reynolds numbers ranges from (1600) to (4000) via using water as the test fluid. The investigational outcomes revealed an enhancement in heat transfer as well as thermal performance of the corrugated tube with MFCI which being significantly augmented in comparison to those for smooth tube. Additionally, the average rise into the value of heat transfer is within (74%) and (90%) at the test range, relying upon the number of cylindrical inserts as well as Reynolds no., whereas the max. thermal performance is obtained to be around (2.4) for utilizing the corrugated tube having (4) cylindrical inserts at low Reynolds no. Furthermore, the outcome of the loss of pressure manifested that the corrugated tube’s mean friction factor is within 96% and 97% more than the smooth tube.