Toronto Metropolitan University Open Journals
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Behaviour of Momentum Boundary Layer and Shear Flow on Darcian Mixed Convection Through a Solid Sphere with Power Law Exponent and Internal HeatGeneration
No full textIn the present study, we are concerned with the shear flow of Darcian mixed convection in a solid sphere with power law exponent and internal heat generation. To follow the Darcy law, the fundamental equations leading PDEs of the model into the nonlinear ODEs using similarity transformation which are tackled by MATLAB bvp4c solver. We found a unique solution (assisting/opposing flow). We inspected the repercussions of relevant parameters such as internal heat generation, power law exponent of velocity (m), power law exponent of temperature (n), velocity profiles and skin fraction coefficient via graphs
Synthesis and Dissipative Particle Dynamics Simulation of New Pseudo-Gemini Surfactant with Piperazine Fragment
No full textA new pseudo-gemini type surfactant with piperazine di-cation and stearate anion was synthesized. Surface activity behavior of the obtained surfactant was investigated by tensiometric measurements, and its Gibbs isotherm was generated. Critical micelle concentration (CMC) of the surfactant was determined by electrolytic conductivity method. The obtained surfactant has a minimum surface tension of 32 mN/m and CMC of 0.509 mM. Dissipative Particle Dynamics (DPD) method was applied to simulate micellization behavior. DPD model successfully displayed micelle formation in the water-surfactant system
Performance Investigation of Pottery Based Evaporative Cooling System working on Thermosyphon and its comparison with Pump Recirculation
No full textThe problems with human comfort are being caused by industrialization and global warming. Evaporative cooling is an economical and ecologically friendly solution for low-income developing nations. Researchers are exploring at employing natural materials like clay pipes and cooling pads made of natural fibers to lessen their impact on the environment and support local farmers and craftspeople. The experimental study of the clay pipe water cooler\u27s performance with pump and thermosyphon water recirculation for the airside and waterside is summarized in this article; additional thermosyphon water recirculation for the system was examined. Thermosyphon water recirculation improves coefficient of performance (COP) by reducing the power input needed for a recirculating pump. When compared to pump recirculation, thermosyphon recirculation of water produced a 40% increase in COP. In order to investigate the thermosyphon ability to recirculate water, a setup was created and the temperature was monitored for 180 minutes at various locations. The findings indicate that, during the course of 180 minutes at an air speed of 4 m/s, the temperature dropped 6.8 0C in the lowest section and 3.4 0C at the topmost position. It was observed that water temperature drop increases with increase in air speed. Water recirculation rate using thermosyphon was dependent on Grashof’s number which increases with time
Performance Enhancement of Miniaturized Solar Cell Using Thermocooler-Ternary Hybrid Nanofluid Combination
No full textThe current paper aims to study numerically the potential enhancement of miniaturized photovoltaic cells using a ternary hybrid nanofluid (THNF) and thermoelectric cooler (TEC). The proposed system, a miniaturized photovoltaic thermal device equipped with a thermoelectric cooler, is subjected to temperatures corresponding to the climatic conditions of the southern region of Algeria (case of Ain Saleh and Bechar). The THNF (Cu-Al2O3-MWCNT/Water) is introduced to the device at a constant horizontal velocity and a uniform temperature. The Maxwell equation governs the thermoelectric effect, and the conduction equation controls the heat transfer in the other solid zones. The THNF flow and heat transfer characteristics are described by momentum and energy equations. The finite elements approach is utilized to solve the system of EDPs based on the Galerkin method. The effect of the inlet velocity on cell performance is analyzed. The findings show improved efficiency and power production when reducing the heat transfer fluid (HTF) velocity. It has also been found that the miniaturized solar cell has a better performance than the conventional solar cell, with an improvement rate that can reach 39.7% if it has a THNF and TEC
Protection of the Environment from pollution by Wastewater from Railway Transport Using Natural Sorbents
No full textThe authors of the article considered the problem of protecting the environment from pollution by surface wastewater from railway transport areas. The possibility of using natural ion-exchange materials (opka, diatomite) in the technology of treating contaminated surface wastewater is considered
Water Structure and Its Influence on Cement Stone and Concrete Properties
No full textObtaining concrete with predetermined properties is the most important task of construction material science. Along with the use of chemical additives of different nature of action in concrete technology, the use of activation of their components, including mixing water, to influence the structure of binding materials is of certain interest. The performed researches are devoted to the study of water structure changes after mechanoactivation in a disintegrator unit. Changes in the pH of water, its electrical conductivity, vapor magnetic properties, and disordered water structure were revealed. The effect of activated mixing water on cement stone structure formation and concrete strength was studied. X-ray phase, thermogravimetric analysis and electron microscopy revealed that mechanoactivation of mixing water changes the kinetics of Portland cement hydration: increases the degree of hydration, accelerates the crystallization of calcium hydroxide, increases the homogeneity of new formations. The use of activated water increases the compressive strength of concrete by (8 -13)% depending on the composition.
The results of studies have shown that mechanoactivation contributes to the increase in the activity of water as a chemical and structure-forming component in binder systems
Criterion For Vibro-acoustic Activity of the Main Sources of Cotton Machines
No full textThe article presents the results of theoretical and experimental studies of the criterion of vibroacoustic activity of the main sources of cotton machines, The proposed criterion for the vibroacoustic activity of a noise source at the stage of designing or composing cotton machines allows us to evaluate the main components of the latter as an emitter of acoustic energy and reveals the connection between the sound power of the source and the loss of mechanical power in this source, establishes the vibroacoustic activity of the sources in relation to the operator’s workplace
Numerical Modeling of Processes with Heat Transfer and Fluid Flow in Complex Situations
No full textThis article discusses in detail the analysis of self-similar solutions based on the global Fujita solvability for the case of doubly nonlinear heat conduction processes with different densities and absorption relative to the source. The work considered is considered very relevant at the present time and is devoted to solving global problems of fluid flow and heat transfer by numerical methods based on good quality properties. The problem considered is close to Busilensky’s models of underwater movements, for the solution of which self-similar and approximate self-similar methods were used. When analyzing solutions, we also encountered some asymptotic cases that revealed new effects. The main results are obtained in numerical cases, 10 bibliographies and one figure are presented
Thermal hydrodynamics of two-phase flow of gas-liquid mixture in power plants
No full textFor numerical study of heat exchange during steam-drop flow in heated channels, single-speed single-temperature models are widely used. In this case, the vapor-droplet mixture is considered as some homogeneous liquid with its own speed and temperature. For the operating conditions of the heated channel of power plants, the temperature of the steam can significantly exceed the temperature of the drops. Not taking into account the real features of heat transfer from the wall to the steam and droplets, and heat exchange between phases limits the application of empirical dependencies to the field of experimental data, according to which dependencies were built. Therefore, to calculate heat dissipation during the steam-drop flow, more accurate two-temperature flow models were developed. Most of these activities take into account the heat flow from the wall to the superheated steam and the heat flow from the superheated steam to the liquid droplets. The disadvantage of the described models is the failure to take into account the heat flow taken from the heated surface by droplets when they collide with the surface. As the results of experimental studies show, the direct thermal interaction of droplets with the heating surface can be decisive in calculating the temperature of the heated surface. For an accurate description of the vapor-droplet flow, it is necessary to take into account the direct thermal interactions of the droplets with the heating surface, as well as the difference in vapor and droplet temperatures
The Method of Improving Fuel Efficiency Indicators and Ensuring Environmental Safety of Gas Cylinder Vehicles in Low Temperature Weather Conditions
No full textThe number of vehicles is increasing, and the energy resources needed for them are lacking. Also, the use of petroleum fuels in vehicles causes their negative impact on the environment to increase. The use of energy-efficient technologies and environmentally safe alternative fuels in the operation of vehicles is currently considered to be very important. Also, technological adjustment of vehicles for different climatic conditions is one of the effective solutions to ensure fuel economy and environmental safety. The scientific paper analyzes the methods of minimizing petrol consumption in low-temperature operating conditions of gas cylinder vehicles (GCV) with a universal fuel supply system running on compressed natural gas (CNG) fuel in order to ensure the operational efficiency and environmental safety of vehicles. Recommendations for saving fuel consumption and ensuring environmental safety of GBA in low-temperature operating conditions have also been developed