Heating Of Cylinder Research Articles

Numerical analysis of evaporation process in the heating column of a solar water desalination plant under various geometries, ambient conditions, solar radiations, and time steps

Solar-powered desalination offers a promising and sustainable method for producing potable water. In this study, the heating column of a solar desalination powerplant is numerically investigated under different novel geometric/structure scenarios, various solar/ambient conditions and different seawater salinity through different time steps. The primary objective is to identify the optimal configuration that maximizes water evaporation within the heating cylinder which has not been carried out before. Initially, four distinct heating cylinder configurations are examined under a fixed time step. The most promising configuration is then selected and evaluated under a broader range of ambient conditions and the same time step. The influence of solar radiation throughout the day is also analyzed. Finally, the evaporation process is simulated for the selected geometrical and environmental conditions across different time steps ranging from 60 to 300 s. The findings reveal that incorporating fins alone, a glass cover alone, and a combination of both fins and a glass cover could enhance the volume fraction of vapor by approximately 8 %, 33.3 % and 10.6 %, respectively, compared to the baseline configuration without fins or a glass cover. However, the evaporation rate for the glass cover configuration increased with rising ambient air temperature. Additionally, the highest evaporation is observed at 15:00 p.m., corresponding to the peak solar radiation intensity. Under optimal conditions, the heating cylinder achieved a promising vapor volume fraction of approximately 78.2 % after 300 s. These findings offer valuable insights for optimizing solar desalination system design. By increasing the salinity of the water from 0 to 75 %, the value of steam volume fraction is reduced from 77 % to 60 % for a given time step.

Optimisation Design of Thermal Test System for Metal Fibre Surface Combustion Structure

The metal fibre surface combustion structure has the characteristics of strong thermal matching ability, short response time, and strong shape adaptability. It has more advantages in the thermal test of complex hypersonic vehicle surface inlet, leading edge, etc. In this paper, a method of aerodynamic thermal simulation test based on metal fibre surface combustion is proposed. The aim of the study was to create a uniform target heat flow on the inner wall surface of a cylindrical specimen by matching the gas jet flow rate and the geometry of the combustion surface. The research adopted the optimisation design method based on the surrogate model to establish the numerical calculation model of a metal fibre combustion jet heating cylinder specimen. One hundred sample points were obtained through Latin hypercube sampling, and a database of design parameters and heat flux was established through numerical simulation. The kriging surrogate model and the non-dominated sequencing genetic optimisation algorithm with elite strategy were adopted. A bi-objective optimisation design was carried out with the optimisation objective of the coincidence between the predicted and the target heat flux on the inner wall of the specimen. The results showed that the average relative errors of heat flow density on the specimen surface were 8.8% and 6% through the leave-one-out cross-validation strategy and the validation of six test sample points, respectively. The relative error values in most regions were within 5%, which indicates that the established kriging surrogate model has high prediction accuracy. Under the optimal solution conditions, the numerical calculation results of the heat flow on the inner wall of the specimen were in good agreement with the target heat flow values, with an average relative error of less than 5% and a maximum value of less than 8%. These results show that the optimisation design method based on the kriging surrogate model can effectively match the thermal test parameters of metal fibre combustion structures.

Physics‐informed learning of chemical reactor systems using decoupling–coupling training framework

AbstractIt is known that physics‐informed learning become a new learning philosophy that has been applied in many scientific domains. However, this approach often struggles to achieve optimal performance in addressing the issue of multiphysics coupling. Here, for the first time, we extend this approach to modeling chemical reactor systems. We design a new decoupling–coupling training framework, which consists of decoupling pre‐training and multiphysics coupling training steps. With decoupling pre‐training, the complex physical domain is decomposed into subdomains of fluid flow, heat transfer, and mass transfer combined with reaction kinetics. Each subdomain is represented by a specialized neural network that can provide a coarse but reasonable distribution of network parameters for initializing the sub‐networks for the subsequent multiphysics coupling training. The capabilities of this approach, in comparison with the traditional CFD simulation, are demonstrated through an example of a plate reactor system with a heating cylinder.

Assessment of Insulation against Contact Heat and Radiant Heat of Composites with TiO2-ZrO2-Al and Parylene C Coatings Intended for Protective Gloves Supported by Computational Fluid Dynamics

This article concerns research on the use of two types of coatings (parylene C and TiO2-ZrO2-Al) in multilayer composites with potential use in metallurgical protective gloves to improve their insulation against contact heat and radiation heat. To evaluate the thermal safety of the glove user, the composites were examined under the conditions of exposure to contact heat (using a heating cylinder, according to EN ISO 12127-1) and radiant heat (using a copper plate calorimeter, according to EN ISO 6942). Moreover, heat transfer through composites exposed to the heat of a hot plate was examined using thermography. The experimental studies were supported by heat transfer simulations through 3D models of composites. The contact heat method showed that composites achieved insulation against contact heat for both contact temperatures Tc, but composites with parylene C have a longer tt of 9 s (for Tc = 100 °C) and 7 s (250 °C) compared to composites with TiO2-ZrO2-Al. The radiant heat method showed that composites achieved the fourth (highest) level of RHTI24 under exposure to a radiant heat flux of 20 kW m−2. The modeling results showed that the parylene C coating increases the thermal barrier of the composite by approximately 10%, while the TiO2-ZrO2-Al coating increases it by 2%. The applied research techniques demonstrated the usefulness of using both types of coatings in the design of metallurgical protective gloves based on multilayer composites.

ВЫБОР ОПТИМАЛЬНЫХ ПАРАМЕТРОВ ПРОСТРАНСТВЕННО-ВРЕМЕННОЙ СЕТКИ ПРИ МАТЕМАТИЧЕСКОМ МОДЕЛИРОВАНИИ НАГРЕВА ЗАГОТОВОК В ПРОМЫШЛЕННЫХ ПЕЧАХ

The efficiency of two numerical methods for solving multidimensional problems of the theory of thermal conductivity ‒ the fractional steps method and the Liebman method - is evaluated. The efficiency of these methods is compared for the operating conditions of industrial furnaces by the example of calculating the symmetrical heating of a two-dimensional cylinder and a three-dimensional plate made of materials with different thermophysical properties (corundum, ceramic brick and carbon steel). A two-dimensional axisymmetric temperature field for a cylinder and a three-dimensional temperature field for a workpiece in the form of a parallelepiped were found by the grid method under boundary conditions of the II and III genera. The difference approximation of differential equations and boundary conditions is performed by the control volume method according to an implicit finite difference scheme. The developed algorithms for solving multidimensional problems of internal heat transfer by fractional steps and the Liebman method are implemented in the form of computer programs in the Object Pascal programming environment. When comparing the effectiveness of solving multidimensional problems with these methods, the criterion of the effectiveness of difference schemes (CERS) proposed by V.V. Bukhmirov and T.E. Sozinova was used as an optimization criterion. Nomograms are constructed to select the optimal parameters of the space-time grid and the best numerical method for solving multidimensional problems for a specific process of heating (cooling) a solid body

FEATURES OF FIRE IN ELECTRIC VEHICLES ON HYDROGEN FUEL CELLS

The purpose of the study is to reveal the characteristics of combustion and hazards arising from fires and traffic accidents involving FCEVs, which will create the basis for new approaches to responding to such events, as well as safe working conditions for rescuers. Description of the material. In general, the fire hazards associated with the use of FCEVs can be divided into the hazards associated with accidental hydrogen leakage and electric shock. Hazards associated with hydrogen arise from the depressurization of mains, which leads to the accidental release of hydrogen into the environment. The release of hydrogen can be long-term or instantaneous as a result of an explosion. Let's analyze the hydrogen supply system used in the FCEV. In general, it can be divided into the hydrogen storage subsystem, the supply subsystem to the fuel cell, and the fuel cell subsystem itself. The hydrogen supply subsystem to the fuel cell carries a greater fire hazard than the fuel cell subsystem. When the line is depressurized, the mechanism for covering the supply of hydrogen from the tank is activated, and the leak stops. However, in the event of ignition, the hydrogen contained in the lines will be sufficient to become a source of ignition for other materials of the vehicle. The hydrogen storage system carries the greatest fire hazard. To prevent an explosion due to heating of a hydrogen cylinder, a pressure valve is used, which is triggered by a thermal sensor when the temperature exceeds 90 ºС. Accidental handling of hydrogen can be accompanied by combustion. And with a faulty attitude valve, the worst situation from the point of view of fire danger can occur - an explosion. Usually, the pressure release valve is placed under the bottom of the car perpendicularly down, or at an angle of 45º. With a hole diameter of 4.2 mm and a hydrogen pressure of 70 MPa, the length of the flame torch when hydrogen leaks in the direction perpendicular to the surface of the earth will be 6.4 m when it leaks at an angle of 45º - 8.8 m, and under the condition of unobstructed combustion, i.e. the car overturned - 10.2 m. When the diameter of the opening increases, the length of the flame torch increases. The heat flow, which is formed due to the burning of hydrogen coming out of the car tank, can be 20 kW/m2 or more at a distance of 2-3 meters from the point of emission. With a heat flow of 1.6 kW/m2, during long-term exposure, there are no painful effects. When the heat flow increases to 4-5 kW/m2, a person who has no means of protection will get a 1st degree burn in 20 seconds; under the action of a heat flow of 9.5 kW/m2, a 2nd degree burn is formed after 20 seconds; 12.5-15 kW/m2 of heat radiation causes a 3rd degree burn. The most dangerous event that can happen for safety reasons is an explosion of a hydrogen tank. Scientists Koshkarov and Molkov investigated the dangerous distances due to the explosion of a hydrogen cylinder. Therefore, in the case of an explosion of a hydrogen cylinder with a volume of 100 l at a pressure of 70 MPa, lethal consequences occur at a distance of up to 8 m, and the zone of severe and medium injuries reaches up to 28 m. The safe distance for such a case is more than 100 m. It is obvious that from the increase pressure and volume of the balloon and such distance increases. Keywords: electric vehicle, hydrogen fuel cell, fire hazard of electric vehicles.

Effect of lossy thin-walled cylindrical food containers on microwave heating performance

Cylindrical containers are commonly used in microwave food processing applications. However, due to the shape effect, microwave energy mainly focuses in the center of the sample within the container, leading to a nonuniform temperature gradient between the inner and outer layers of the sample. Employing a lossy container may be an effective method to address this issue because the heat conduction from the container's wall or the microwave's interaction with the container edge can compensate for the lack of heating in the outer layer. Multiphysics modeling is a powerful tool for uncovering the effect of the lossy container on microwave heating performance. However, noncompliance between the fine and coarse mesh elements at the thin-walled boundary of the container will generate a huge number of irregular meshes, which will not only lead to excessive computational costs but also lead to the possibility of calculation error of the boundary flux. To overcome this difficulty, a fast simulation method based on transformation optics is proposed to analyze the effect of lossy containers on microwave food processing performance in this paper. By using the proposed method, the calculation efficiency can be increased by up to 800% with comparable or even better accuracy than the traditional method. Meanwhile, the results show that the lossy container can improve the temperature uniformity around microwaved food but it will slightly reduce the heating efficiency due to energy loss within the container. This paper offers an efficient and fast way to analyze microwave food heating processes with a thin-wall structure. Furthermore, the discussion on the feasibility of using lossy containers to improve the microwave heating uniformity will also contribute to the further application of microwave cylindrical food processing. • Microwave heating models with lossy thin-walled cylindrical containers were realized by transformation optics. • Compared with traditional method, this method can improve the computing efficiency by 8 times with a wall thickness of 1 mm. • The influence of container's material, size and wall thickness on microwave heating is analyzed. • Employing lossy container can weak the phenomenon of thermal focus during microwave heating cylinder food.

Dynamics of nonlinear-shaped solid particles occurrence of hydro-magnetic slip with comparative analysis of radiated ternary, hybrid and nanofluid flow in a rotating internally heating cylinder

Nowadays, the heat thrust liquid electric heater is generally used in profitable applications since it protects upto 2–3 times the energy of ordinary liquid electric heater. The heat pump makes use of a refrigerant for its process. The small-temperature refrigerant engrosses permitted heat from full of atmosphere midair in the evaporator which is crushed by an extremely well-organized electrical compressor to an extraordinary-temperature and high-pressure vapor refrigerant. For entire heat transfer connoisseurs, heat transfer performance in cooling and heating applications has become a top priority. Hence, research towards new heat transfer fluids is extremely intense and challenging. This investigation examines flow and heat transfer analysis in axisymmetric magnetohydrodynamic flow polyethylene glycol (PEG)-based nanofluid, hybrid nanofluid and ternary hybrid nanofluid flow induced by a swirling cylinder. Flow and heat transfer are analyzed and compared for three cases PEG-based copper oxide, magnesium oxide and zirconium oxide ternary nanofluid (PEG[Formula: see text][Formula: see text][Formula: see text]ZrO2[Formula: see text][Formula: see text][Formula: see text]CuO[Formula: see text][Formula: see text][Formula: see text]MgO), PEG-based copper oxide (PEG[Formula: see text][Formula: see text][Formula: see text]CuO) nanoparticles and PEG-based zirconium and magnesium oxide hybrid nanofluid (PEG[Formula: see text][Formula: see text][Formula: see text]ZrO2[Formula: see text][Formula: see text][Formula: see text]MgO). Shooting technique (R–K fourth-order) is employed to work out the flow equations numerically. Simulated results are displayed through graphs. The computational results are validated with the published research work and a modest concurrence is found. The main outcome of this study is found to be as follows: It is interesting to note that [Formula: see text] is lesser in nanofluid case compared with ternary and hybrid nanofluid cases. It is found that [Formula: see text] is more in ternary hybrid nanofluid compared with hybrid and nanofluid cases. Overall, it is observed that heat transfer rate is higher in nanofluid compared with ternary and hybrid nanofluid cases whereas lesser rate of heat transfers in ternary nanofluid case.

Experimental study on thermal and friction characteristics of liquid flow across a heating cylinders under low-frequency ultrasound

• The heat transfer of water flow across a cylinder under a 25 kHz ultrasound was studied. • Visualization by TLCs on shaded surface was achieved using unique image processing. • Heat transfer area on cylindrical surface could be identified by TLCs. • The waves emitted downstream could affect the cylindrical surface at the upstream. • A prediction formula for Nu of the flow across a cylinder under ultrasound was proposed. The heat transfer capability was investigated for water flow across a cylinder under the influence of 25 kHz ultrasound in a rectangular duct with a Reynolds number ( Re ) in the range of 110–2,140. A heating cylinder with constant heat flux was set at the center of the duct. The transducer was mounted on the top wall, and its location was set at -2, -1, 0, +1, and +2 diameters from the cylinder in the streamwise direction. Thermocouples and thermochromic liquid crystals (TLCs) were used to characterize the heat transfer mechanism on the heating surface. In particular, a visualization technique using TLCs was developed to obtain temperature results on a cylindrical surface. The temperature of the heating surface was reduced by the acoustic cavitation process with ultrasonic involvement. The local Nusselt number was increased by 2.37-fold by the waves at a cylindrical angle of 90° and Re value of 110 when the transducer was also located in the middle of the duct. Furthermore, the results indicated that ultrasonic effects could be transported along with the flow when the transducer was located upstream. In addition, when the waves were released downstream, they affected the heat transfer of the cylindrical surface at low Re values. The friction loss in the system was investigated by comparing the pressure drops with and without ultrasound. Depending on the position of the ultrasonic transducer, the pressure drop ratio was in the range 0.88–1.27. Furthermore, the areas most affected by ultrasound were identified using the TLC measurement method, and regions of augmented heat transfer were detected locally on the shaded and unshaded sides of the cylinder. A predictive formula was proposed for the local Nusselt number ratio with and without ultrasound as a function of the Re value, spanwise direction, and cylindrical angle.

Numerical modeling of heat transfer performance and optimization of car radiator using (H2O/Al2O3) nanofluids as coolant

The combustion of fuel in an engine is an exothermic reaction that releases a tremendous amount of heat. Some of this heat is escapes with the exhaust gases while the remaining is absorbed by the engine parts. Excessive heating of the engine cylinder can lead to the premature detonation of the air-fuel mixture in the cylinder, piston scuffing, damage of valves and guides, thermal stress buildup and gasket failure. Most engines utilize a liquid cooling system to transfer the heat from the engine to the surroundings. The radiator is a vital part of an automobile cooling system. Water and other coolants such as ethylene glycol are usually applied to dispel heat from the engine to the environment through the radiator. Nanofluids have a higher thermal conductivity than water and ethylene glycol, and for this reason, it has been receiving attention as a better alternative to the conventional coolants. In this study, the thermal performance of water and aluminum oxide nanofluids were investigated numerically. The radiator understudy was a crossflow radiator. Solidworks 2017 flow simulation software was used to carry out the numerical investigation. The same inlet temperature, flow rate and environmental conditions were used for both the water and nanofluid coolant operating in the radiator. Four different concentrations of the nanofluid were considered in this study, to determine the effect of concentration on the performance of the radiator. At a 1% concentration of Al2O3, the enhancement in the heat transfer rate and heat transfer coefficient (coolant side) are 0.86% and 6.98% respectively. While at 4% concentration, the enhancement in heat transfer rate and heat transfer coefficient is 12.03% and 14.31% compared to water. The results of this study prove that nanofluid is a better heat transfer fluid compared to water and serve as a better alternative for application in car radiators.

Mathematical modeling of systems for automatic control of the material cylinder heating zones for extrusion unit

Mathematical modeling is carried out to determine the optimal temperatures in the zones of the material cylinder for the extrusion unit. The transfer function of the material cylinder is obtained. The optimal tuning coefficients for the proportional-integral-differential adjustment law are calculated. Modeling of the temperature control system with optimal controller parameters in the VisSim environment is performed. A graph of the transient process with a PID controller is built. The obtained data of mathematical modeling and calculation of the optimal coefficients for the PID controller can be used to adjust the temperature on the material cylinder in the production of plastic pipes by extrusion. Keywords automatic control system, extrusion, mathematical modeling, adjuster

Thermal impacts on nondestructive analysis measurements of uranium hexafluoride

A series of nondestructive assay measurements were performed before, during, and after localized heating of an industrial standard 12B cylinder of uranium hexafluoride to replicate dose variations previously observed on commercial 30B cylinders. While cylinders represent a closed system, enrichment measurements may be impacted by altered uranium and daughter product distributions due to sublimation. A series of measurements were performed to examine localized heating impacts on dose rates, ratios of uranium and daughter product distributions, and measured 235U enrichment as calculated by two different approaches. The less complex enrichment meter approaches were found to be more robust and less prone to deviation than isotope ratio approaches such as FRAM, but the impact can be minimized by using observable dose changes to avoid impacted areas.

Pumping gaseous CO2 into a high-pressure, constant-volume storage cylinder: A thermodynamics analysis

A thermodynamic model is developed to predict the pressure, temperature, and density of CO2 when it is compressed into a high-pressure, constant-volume storage cylinder. The model incorporates the effects of the compressibility of the fluid. Heat loss to the surrounding environment and heating of the cylinder walls are also considered. The basic equations are non-dimensionlized. Variations of CO2 pressure, temperature, and density inside the cylinder during the pumping process are investigated using the heat loss to the surrounding, the heat used to heat the cylinder walls, and the compression power as the parameters. The results show that CO2 pressure is not sensitive to the heat loss, but it does depend on the compression power. For the range of the heat loss and the cylinder heating that are found in many practical situations, CO2 temperature inside the cylinder increases to a maximum value of about 7 K above the surrounding temperature, and the pumping can be modeled as a polytropic process, where PVn=constant with the polytropic exponential power n = 0.995.

Analysis of Thermodynamic Parameter Variability in a Chamber of a Furnace for Thermo-Chemical Treatment

This paper presents results of research on unevenness of cylinder heating in a furnace for thermo-chemical treatment. Experimental research was conducted with respect to nitriding. Various heating speeds and settings of the fan operation in the furnace were considered. Boundary conditions were calculated in the form of temperature and the heat transfer coefficient (HTC) on the cylinder boundary in four planes along the cylinder length. Calculations were performed with the use of the inverse problem for non-linear and unsteady heat conduction equations. Boundary conditions from individual planes were compared with the mean value of them all. The variability of the calculated boundary conditions (temperature and HTC) along the cylinder length was investigated based on values of the absolute and relative differences for temperature and HTC. Estimates: mean value, mean value from the absolute value and the maximum values for the absolute and the relative differences of temperature and HTC were also calculated. Estimates were the measurements of the unevenness of cylinder heating in a furnace for thermo-chemical treatment. Based on the results of our research, it was found that an increase of the fan rotational speed from 50% to 100%, with the same heating speed, resulted in a significant leveling of temperature in the analyzed planes. The difference in temperature along the cylinder length was reduced from 6.8 °C to 3.3 °C. The increase of the heating speed from 5 °C/min to 10 °C/min resulted in an increase of the unevenness of the cylinder heating. Values of the absolute differences of temperature in the analyzed planes with reference to the mean temperature changed from an interval from −2.7 °C to 2.3 °C to a range from −4 °C to 5 °C. In processes with a heating speed greater than 5 °C/min, more intensive heating in the end part of the cylinder (close to the cylinder) was achieved than it was in other planes. It was proven by temperature values, which were higher, even, by 5.4 °C, and by HTC values, higher by 11.4 W/m2K, when compared with mean values. Obtained results can form the basis for nitriding process optimization.

Thermal characterization of a heating cylinder under ultrasonic effects

Ultrasonic effects were investigated on the heat transfer characteristics of a vertical cylinder releasing a constant heat flux of 14,150 W/m2 in distilled water. A triple-frequency ultrasonic transducer was installed at the center of the lateral wall of the cubic test section to emit 40, 80, and 120 kHz ultrasonic waves. The thermal characterization was investigated by varying the distance (5, 10, and 15 cm) between the ultrasonic transducer and the heating surface. The surface temperature of the heater, detected using 12 thin-leaf thermocouples, decreased rapidly because of the ultrasonic effect, leading to an increase in the Nusselt number. An infrared camera and a video camera were used for the visualization and investigation of acoustic streaming and acoustic cavitation. The results showed that ultrasound enhanced heat transfer to the maximum level of 82.4% using 40 kHz waves at a distance of 5 cm. At distances of 10 and 15 cm, 120 kHz ultrasonic waves produced the highest heat transfer enhancement levels of 74.2% and 59.7%, respectively. The heat transfer enhancement ratio decreased with increasing incident angle of the wave beam as well as with the distance between the ultrasonic transducer and the heating surface. The key mechanisms leading to the enhancement of heat transfer in the near and far fields were identified and discussed. Finally, an accurate prediction formula was proposed for the overall heat transfer enhancement ratio, depending on the ultrasonic frequency and distance.

Investigation of Microclimate Ventilation of Simulated Garment in Terms of Wind Speed and Air Gap Thickness

During the circulation of air in the garment’s microclimate, the body extra heat dissipates to the environment. This event is an important factor in thermal comfort and ventilation. In this study, a heating cylinder was designed and calibrated to assess the ventilation occurrences in garment as a simulator of the human body. Tubular samples with different sizes were prepared using double jersey weft knitted fabric in order to obtain five levels of air gap thickness, including −1.5, 0, 1, 1.5 and 2 cm. Experiments were carried out in two conditions including without wind and by wind blowing with eight different wind speeds include 0.5, 1, 1.5, 2, 2.5, 3, 5 and 7 m/s. In each condition, the air gap’s temperature was considered as the main parameter for examination of the microclimate ventilation. The obtained outcomes revealed that by increasing the air gap thickness to more than 1 centimetre, the ventilation rate increased significantly. In the absence of wind, the change in the air gap’s temperature was not considerable for all sizes due to the natural convection phenomena that were slow. An increase of wind speed to more than 1 m/s led to a rise in the forced convection heat loss and took less time for the system to reach the equilibrium temperature; hence, higher ventilation rate was achieved. Moreover, by the increment of wind speed, the reduction of microclimate temperature follows a power function and at higher wind speeds remained approximately constant. According to the statistical analysis of results, it was confirmed that the ventilation rate of garment was influenced by wind speed; however, the influence of air gap thickness only in the absence of wind is significant.

Taylor–Couette flows undergoing orthogonal rotation subject to thermal stratification

The present study involves direct numerical simulation of turbulent Taylor–Couette flow undergoing orthogonal rotation (gravity and rotation axis are perpendicular) subject to thermal stratification in the radial direction. The simulations were performed based on the finite-difference approach for a radius ratio (η) = 0.5 and an aspect ratio (Γ) = 2π, with Reynolds number (Re=UθDν) ranging from 1000 to 5000. For this wide gap, the role of spatially varying buoyancy forces (Ri ranging from 0 to 0.3) in flow physics has been explored using flow statistics, flow dynamics, near-wall coherent structures, and quadrant analysis. It is observed that near-wall streaks are concentrated at the outflow boundaries of Taylor vortex cells with uniform axial spacing, which decreases with the increasing Reynolds number. Heating of the outer cylinder results in more intense streaks and coherent structures in the half-circumferential domain due to unstable stratification aiding turbulence, while in the other half-domain, stable stratification mitigates turbulence. Quadrant contribution of ur′ and uθ′ reveals that on heating the outer cylinder, there is an increase in turbulence near both the walls due to the enhanced generation of Reynolds shear stresses (sweep and ejection events).

Three-Dimensional (3D) Visualization and Two-Dimensional (2D) Second Law Analysis of Magnetohydrodynamic (MHD) Free Convection Inside Cubical Enclosure Packed with Hybrid Nanofluid Containing a Circular Heating Cylinder: Effect of Inclined Magnetic Field

In the present work, an irreversibility analysis of three- (3D) and two-dimensional (2D) magnetohydrodynamic (MHD) free convection inside cubical enclosure packed with hybrid water nanofluid (alumina, titanium dioxide and copper) is carried out. The discretization of the momentum and energy equations is done by employment of finite volume approach with SIMPLE algorithm. The effect of inclined magnetic on the heat transfer rate and various entropy types is investigated. All numerical tests are obtained for various Rayleigh numbers 103 ≤ Ra ≤ 106, Hartman numbers 0 ≤ Ha ≤ 45, hybrid nanoparticles percentage 0 ≤ φ % ≤ 5%, and the magnetic field angle 0 ≤ α≤90°. The Bejan number is used in this study to show the entropy type dominant. The first part of this study is about showing a three-dimensional shape of the particles trajectory, isotherms, local Bejan number and different local entropy types; then the second part is limited to a two-dimensional study of all physical quantities. As main results, it is demonstrated that the rate of heat transfer and entropy creation are significantly improved by changing the Rayleigh number, Hartmann number and the magnetic field angle. Moreover, it is also found that the effect of increasing the volume fraction of hybrid nanoparticles can be optimized to get good enhancement of heat transfer rate.

Visualization Analysis of Plastication Process in Vent-type Heating Cylinder

Visualization Analysis of Plastication Process in Vent-type Heating Cylinder

Effects of the heating temperature during the press extraction process on the yield and quality of cosmetic argan oil

The effects of the temperature of the heating ring of the extraction cylinder during the press extraction of argan oil from unroasted kernels on the oil extraction yield and quality were investigated. Oil extraction experiments were carried out with an Ateliers Afyach P55 mechanical screw press that had one press cylinder equipped with a heating ring located on the outlet side. Tested heating ring temperatures were 60, 80, 100, 120, 140, and 160 °C, and a medium screw rotational speed of 5 rpm was applied. The temperature was monitored during the extraction process along the cylinder and at the oil outlet. Results showed a significant effect of the cylinder heating ring temperature on the oil extraction yield; higher yields were obtained in the 80–120 °C range, with the highest values obtained at 80 °C for crude oil and clarified oil (53–55% and 47% wt/wt, respectively). At 60 °C, the oil extraction process was difficult to realize because the cylinder jammed due to the presence of a considerable amount of residue particles in the extracted oil. The measured temperatures at different points along the press cylinder during the extraction process and the temperature of the oil extracted during the process were much lower than the temperature of the heating ring. The extracted oil temperature ranged between 45 and 68 °C. In addition, even though the effects of the temperature on the monitored quality parameters (free acidity, peroxide value, and UV absorbance) were significant, all of the extracted oils were of extra virgin grade. These results imply that heating the ring of the extraction cylinder to approximately 80 °C optimizes the performance of the press and results in a high oil yield without compromising oil quality.