Numerical Modeling of Disperse Materials Process in a Continuous-Flow Plasma Reactor

The paper presents a numerical simulation of the propagation of the direct-flow temperature plasma reactor, which is solved by the compressible Navier–Stokes equations, numerical algorithm based on SIMPLE algorithm that are approximated by finite volume method. In the numerical solution of the equation system can be divided into four stages. The first stage the transfer of momentum carried out only by convection and diffusion. The intermediate velocity field is solved by the solution of the differential velocity gradient equation, the Green-Gauss Cell Based scheme is used. The second stage for the pressure field, PRESTO numerical scheme is applied. In the third step it is assumed that the transfer is carried out only by the pressure gradient. The fourth step of the equation is solved for the temperature transport equation as well as the momentum equations by the Green-Gauss Cell Based scheme is used. The algorithm is parallelized on high-performance systems. With this numerical algorithm numerical results of temperature distribution in a continuous-flow plasma reactor was obtained. Numerical modeling allows us to give a more precise description of the processes that have been identified or studied theoretically by laboratory methods, and can reveal new physical phenomena processes that are not yet available, seen in experimental studies. Simulation results show that the constructed numerical model provides the necessary accuracy and stability, which should accurately describe the process during the time interval

Convective heat transfer for Peristaltic flow of SWCNT inside a sinusoidal elliptic duct

A mathematical model is presented to analyse the flow characteristics and heat transfer aspects of a heated Newtonian viscous fluid with single wall carbon nanotubes inside a vertical duct having elliptic cross section and sinusoidally fluctuating walls. Exact mathematical computations are performed to get temperature, velocity and pressure gradient expressions. A polynomial solution technique is utilized to obtain these mathematical solutions. Finally, these computational results are presented graphically and different characteristics of peristaltic flow phenomenon are examined in detail through these graphs. The velocity declines as the volume fraction of carbon nanotubes increases in the base fluid. Since the velocity of fluid is dependent on its temperature in this study case and temperature decreases with increasing volumetric fraction of carbon nanotubes. Thus velocity also declines for increasing volumetric fraction of nanoparticles

Computational Fluid Dynamics Analysis of Flow Patterns, Pressure Drop, and Heat Transfer Coefficient in Staggered and Inline Shell-Tube Heat Exchangers

In this numerical study, the heat transfer performance of shell-and-tube heat exchangers (STHXs) has been compared for two different tube arrangements. STHX having 21 and 24 tubes arranged in the inline and staggered grid has been considered for heat transfer analysis. Shell-and-tube heat exchanger with staggered grid arrangement has been observed to provide lesser thermal stratification as compared to the inline arrangement. Further, the study of variation in the mass flow rate of shell-side fluid having constant tube-side flow rate has been conducted for staggered grid structure STHX. The mass flow rate for the shell side has been varied from 0.1 kg/s to 0.5 kg/s, respectively, keeping the tube-side mass flow rate as constant at 0.25 kg/s. The influence of bulk mass-influx transfer rate on heat transfer efficiency, effectiveness, and pressure drop of shell-tube heat exchangers has been analyzed. CFD results were compared with analytical solutions, and it shows a good agreement between them. It has been observed that pressure drop is minimum for the flow rate of 0.1 kg/s, and outlet temperatures at the shell side and tube side have been predicted to be 40.94°C and 63.63°C, respectively

Analysis of NMR Spectra of Submicro-Containers with Biocide DCOIT

Nowadays, the search for and development of new forms of materials with biocides is an actual problem of the modern science of nanosized materials due to the problem of microbiological contamination, which can be solved by using nanocontainers carrying biocides. Depending on the morphology of the nanocontainers and the filled active agents, it is possible to create coatings with specially designed self-healing functionality or multifunctional properties. The purpose of this work was to produce submicro-containers (SMCs) with a shell of SiO₂ nanoparticles and a core of polymerized 3-(trimethoxysilyl) propyl methacrylate filled with 5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) in an oil in water (O/W) emulsion. The chemical nature of the individual components of the system and nano-capsules were investigated using NMR spectroscopy. The size and zeta potential of the SMCs were measured by a dynamic light scattering method (d = 170–180 nm, polydispersity index PDI = 0.125 and zeta-potential = 55 mV), the morphology of their outer surface was determined using SEM. The results of NMR analysis showed that during the addition of the biocide into the SMCs, its chemical structure is retained, as is its activity. Minor changes in the chemical shifts of the ¹H NMR spectra of the SMCs with DCOIT, as well as of the biocide itself, confirm the inclusion of DCOIT inside the SMCs

Energy, Exergy Analysis, and Optimizations of Collector Cover Thickness of a Solar Still in El Oued Climate, Algeria

Researches in many laboratories on solar still desalination are concerned with increasing efficiency using only solar energy. One of the techniques is the difference in the thickness of the glass cover of the distiller. In order to see the influence of this parameter on efficiency, three similar stills with three different glass coverings were investigated. The flow of heat goes through the cover, and higher glass temperature leads to solar still productivity becoming lower. This paper presents an optimization of glass thickness (Gt) of a conventional solar still (CSS) in El Oued climate, Algeria. Based on the experimental results, the distilled water production rate, energy, and energy efficiency of the CSS have been discussed. The results showed that the suitable Gt of the CSS was 3 mm. The distilled water of around 3.15, 2.02, and 1.13 kg was produced by the CSS at energy efficiency of 30.71, 19.02, and 11.44% with the Gt of 3, 5, and 6 mm, respectively. The daily average exergy efficiency of 2.46, 1.38, and 0.84% was calculated for the CSS at Gt of 3, 5, and 6 mm, respectively

Effect of Reflecting Material on CPC to Improve the Performance of Hybrid Groundwater Solar Desalination System

Water-energy nexus is a crucial and challenging concern that addressing it is noteworthy for the future of human beings. In addition, freshwater production is a highly energy-intensive procedure. Therefore, developing a suitable solution for this problem is of importance. In the present scenario, solar energy is one of the suitable options for desalination because solar energy is available at a low cost, is clean for the environment, and is widely available. Generally, solar collectors such as flat plate collectors (FPC) and evacuated tube collectors were experimented for desalination applications. This work presents an experimental investigation of a single-stage hybrid (ETC-CPC) groundwater solar desalination system. A compound parabolic concentrator (CPC) is placed below the evacuated tube collector (ETC) for collecting solar radiations to transfer heat to evacuated tubes which improves performance in the case of different weather conditions of Pune city in India. Experimental results show that the hybrid solar groundwater desalination system, by maintaining the optimum distance of 20 mm between ETC and CPC with Mylar as the reflecting material, could offer a drinking water production rate of up to 3.4 l/(m2h)/day. However, the proposed single-stage hybrid (ETC+CPC) groundwater solar desalination system with aluminum foil as a reflecting material could generate 1.9 liters of soft water per day. Further, the use of Mylar as a reflecting material could generate 3.5 liters of soft water per day

Briquetting of Dry Sugarcane Leaves by Using Press Mud, Cow Dung, and Buffalo Dung as Binders

The world’s population is increasing rapidly. This means that energy consumption and demand for energy are also increasing at the same rate. It is estimated that energy will need to be provided to 9 to 10 billion people by 2040. India is a leading consumer of energy in the world. In particular, it consumes a large amount of oil and natural gas to fulfil its energy demand. Due to uncertainty in the supply of oil and natural gas and their prices as well as environmental pollution, there is a need to shift towards other energy sources. Biomass is one of the first energy sources with specific properties and abundant availability. Today, 10% to 14% of the world’s energy supply is provided by biomass sources. Using agricultural waste (biomass) to make briquettes to generate power can be an alternative solution to the problems related to their disposal and pollution. The present work investigates the optimum ratio of dry sugarcane leaves to binders and optimum load and selects the best binder (cow dung, buffalo dung, and press mud) for making high-quality briquettes. The physical parameters and proximate analysis of the dry sugarcane leaf briquettes with the cow dung, buffalo dung, and press mud binders are investigated. The dry sugarcane leaf briquettes with the cow dung binder have the highest gross calorific value, net calorific value, split tensile strength, tumbling resistance, shatter resistance, and energy density ratio (16262.31 kJ/kg, 15362.1 kJ/kg, 7.164 kN/m2, 87.84%, 12.75%, and 0.9296, respectively). The estimated results show that cow dung is a better binder for making high-quality dry sugarcane leaf briquettes than the buffalo dung and press mud binders