Research on Deposition of Micro-Nano Aerosols in Rising Bubble Under Pool Scrubbing Condition

2018 ◽  
Author(s):  
Yanmin Zhou ◽  
Haifeng Gu ◽  
Qiunan Sun ◽  
Zhongning Sun ◽  
Jiqiang Su ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Bubbly Flow ◽  
Aerosol Deposition ◽  
Deposition Efficiency ◽  
Filtration Efficiency ◽  
Liquid Level ◽  
Gas Flow Rate ◽  
Reactor Accident ◽  
Rising Bubble

Aerosols as the main component of radioactive products in migration performance, which is an important factor that a unclear reactor accident present strong diffusion and affects the distributions of source and dose level in reactor containment, and they are therefore expected to be deposited in liquid phase such as in suspension pool and filtered containment venting device. In this paper, the deposition characteristics of micro-nano aerosols in rising bubble under pool scrubbing condition is studied with experiment, the aerosols size in the research range from 20 nm to 600 nm, and the bubble morphology mainly concern homogeneous bubbly flow. The results show that the deposition efficiency and mechanism of aerosol closely relate to gas flow rate, liquid level, particle size and bubbles size and so on. The aerosol deposition near 85nm is proved most difficult because of the convert of deposition mechanisms. In a high liquid level condition, micro-nano aerosol filtration efficiency is enhanced but gradually gradual. Under different gas flow rate, air bubble residence time and the bubble size distributions affect the filtration efficiency of aerosols.

A Taguchi Design Study for Optimisation of Plasma Sprayed Hydroxyapatite Coatings

2013 ◽  
Vol 773-774 ◽  
pp. 590-601
Author(s):  
Md Fahad Hasan ◽  
James Wang ◽  
Christopher C. Berndt
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Flow Rate ◽  
Feed Rate ◽  
Gas Flow ◽  
Deposition Efficiency ◽  
Gas Flow Rate ◽  
Powder Feed Rate ◽  
Hydroxyapatite Coatings ◽  
Plasma Sprayed

Plasma sprayed hydroxyapatite coatings were deposited onto mild steel substrates. A Taguchi L9design of experiment protocol was used to optimise the coating process parameters. The effect of three factors: (i) power and secondary gas flow rate (X1), (ii) powder feed rate and carrier gas flow rate (X2), and (iii) stand-off distance (X3) on the coating responses was studied. The responses of the plasma sprayed hydroxyapatite coatings were evaluated in terms of porosity, deposition efficiency, microhardness, crystallinity, and surface roughness. A regression analysis established relationships between process parameters and responses. Higher power, lower powder feed rate and the middle stand-off distance of 11 cm lead to optimum attributes of low porosity, high deposition efficiency, high microhardness, high crystallinity, and high surface roughness.

Dependence of Gas Bubble Diameter from the Gas Flow Rate in Upward Two-Phase Flow in an Inclined Flat Channel

2014 ◽  
Vol 9 (2) ◽  
pp. 136-144
Author(s):  
Anastasia Gorelikova ◽  
Oleg Kashinsky ◽  
Vyacheslav Randin ◽  
Aleksandr Chinak
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Gas Flow ◽  
Bubbly Flow ◽  
Bubble Diameter ◽  
Flow Rate Ratio ◽  
Flat Channel ◽  
Gas Flow Rate ◽  
Two Phase ◽  
Gas Liquid Flow

Experimental study of heat transfer and wall shear stress in an upward bubbly flow in an inclined flat channel is presented. The measurements were performed in the range of superficial liquid velocities 0.31.1 m/s and different values of volumetric gas flow rate ratio. Measurements of hydrodynamic structure were carried out by electrochemical method using a miniature sensors of friction. The values of average friction and heat transfer coefficient at different orientations of the channel were determined. It is shown that there is a significant dependence of friction and heat transfer on the channel inclination angle in the gas-liquid flow

SCIENTIFIC AND ENGINEERING PRINCIPLES OF EFFICIENT FUEL USE AND ENVIRONMENTALLY FRIENDLY GAS COMBUSTION IN STOVE PLATES. PART 1. MODERN STATE-OF-THE-ART AND DIRECTIONS FOR IMPROVEMENT THE GAS BURNING IN DOMESTIC GAS COOKERS

2017 ◽  
pp. 3-18 ◽  
Author(s):  
B.S. Soroka ◽  
V.V. Horupa
Keyword(s):  
Natural Gas ◽  
Flow Rate ◽  
Gas Flow ◽  
Renewable Energy Sources ◽  
Combustion Process ◽  
Orifice Diameter ◽  
Firing Process ◽  
Gas Flow Rate ◽  
Gas Combustion ◽  
Gas Stoves

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.

On the Influence of Fluctuating Flow Rate Upon the Performance and Behaviour of Isothermal Reacting Systems

1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Fluidized Bed Reactor ◽  
Computational Techniques ◽  
Continuous Stirred Tank Reactor ◽  
Gas Flow Rate ◽  
Solid Reaction ◽  
Continuous Stirred Tank ◽  
And Performance ◽  
Reacting Systems

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.

scholarly journals Investigation on influences of loose gas on gas-solid flows in a circulating fluidized bed (CFB) reactor using full-loop numerical simulation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Separation Efficiency ◽  
Circulation Rate ◽  
Solid Mass ◽  
Gas Flow Rate ◽  
Gas Leakage ◽  
Mass Circulation

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.

Sign in / Sign up

Export Citation Format

Share Document