scholarly journals Study of the optimal placement of exhaust ventilation equipment in a poultry house using numerical simulation

2020 ◽  
pp. 89-101
Author(s):  
V. Trokhaniak ◽  
Keyword(s):  
Mass Transfer ◽  
Numerical Modeling ◽  
Heat And Mass Transfer ◽  
Egg Production ◽  
Air Flow ◽  
Ventilation System ◽  
Optimal Placement ◽  
Feed Consumption ◽  
Poultry House ◽  
Exhaust Ventilation

Keeping poultry in damp and cold rooms with poor ventilation system reduces the weight gain of the bird, reduces its egg production and increases the incidence of young animals, as well as excessive feed consumption and exceeding the growing period established by technical regulations. The aim of the study was to determine the effective placement of exhaust ventilation equipment at the height of the end wall of the poultry house to improve the ventilation system, reduce stagnant air zones and improve the microclimate. The numerical modeling of hydrodynamics, heat and mass transfer processes during air ventilation in poultry buildings is carried out. The analysis of the conditions of heat and mass transfer in the poultry house, depending on the placement of fans along the height of the house, and the efficiency of the location of such equipment was determined. The system for maintaining the microclimate in poultry houses was considered in the presence of a system for cooling the outside air with water from an underground well. The ventilation system uses exhaust ventilation equipment with a fan wheel diameter of 1.25 m. In the simulation, the fans were installed at a height of 1.125, 1.5 and 1.875 m from the floor to the center of the fan axis. Simulation was performed for 2D CFD models using ANSYS Fluent software. The results of CFD analysis of the air flow pattern and the thermal state inside the house are presented. As a result of numerous studies, the geometry of the location of the ventilation equipment has been found. It is shown that it is advisable to install ventilation equipment at a height of 1.5 m. At the same time, the size of stagnant zones and the uneven distribution of air velocity near the bird are reduced. Numerical modeling was carried out in order to minimize the size of stagnant zones, equalize the air flow and improve the temperature indicators in the poultry house.

Thermal convection in melting zone of hollow microparticle Al2O3

2021 ◽  
pp. 20-25
Author(s):  
V.V. Shekhovtsov ◽  
◽  
YU.A. Abzaev ◽  
O.G. Volokitin ◽  
A.A. Klopotov ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Numerical Modeling ◽  
Liquid Phase ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Thermal Convection ◽  
Melting Zone ◽  
Melting Front ◽  
Α Al2o3 ◽  
Inner Region

The paper presents the results of numerical modeling of development melting zone hollow spherical microparticle α-Al2O3. The object of the study was part circular sector, which represents the shell of hollow particle, which is formed under action plasma flow. Numerically describe the unsteady convective heat and mass transfer in shell hollow particle, we used the system Navier-Stokes equations in Boussinesq approximation, which describes the weak convection medium. Due to the high coefficient of porosity (P = 0.56) initial agglomerated particle with the α-Al2O3 structure, the inner region at the stage of heating Tp ≥ Tmelt is in the conditions heat exchange with the incoming heat flux, as result of which the temperature center coincided with the temperature particle surface. Result of overheating of the condensed phase, liquid layer of fused grains is formed in the inner and outer regions microparticle. In this case, the melting front is directed towards center shell. Result of numerical modeling, it has been established that convective heat and mass transfer is observed in melting zones (liquid phase), vector field of which covers almost the entire region of the liquid phase. It was found that thermal convection in the external liquid phase is characterized by velocities that are more than 2 times higher than the displacement velocity in the inner region of the particle. It is shown that there is no displacement of the material inside the convection region, thereby inhomogeneous heating occurs in the molten layer of the particle, which significantly affects the speed of movement of the melting front.

Influence of shrinkage during natural rubber sheet drying: Numerical modeling of heat and mass transfer

2019 ◽  
Vol 149 ◽  
pp. 798-806 ◽  
Author(s):  
Clement Ajani ◽  
Stefano Curcio ◽  
Racha Dejchanchaiwong ◽  
Perapong Tekasakul
Keyword(s):  
Mass Transfer ◽  
Numerical Modeling ◽  
Natural Rubber ◽  
Heat And Mass Transfer ◽  
Rubber Sheet

Air Flow Straighteners’ Application to Reduce the Power Consumption of Exhaust Ventilation Schemes

2018 ◽  
Vol 875 ◽  
pp. 137-140 ◽  
Author(s):  
Valery N. Azarov ◽  
Natalia M. Sergina ◽  
I.V. Stefanenko
Keyword(s):  
Power Consumption ◽  
Air Flow ◽  
Ventilation System ◽  
Aerodynamic Resistance ◽  
Experimental Studies ◽  
Swirling Flows ◽  
Dust Collector ◽  
Exhaust Ventilation ◽  
Outlet Pipe ◽  
Ventilation Systems

It was proposed to use air flow screw straightened units in outlet pipe of the dust collectors to reduce the aerodynamic resistance of exhaust ventilation systems. It is allowed to decrease power consumption for their maintenance operation consequently. The article describes the results of experimental studies to evaluate its effectiveness by applying the tangential screw straightened unit within ventilation system. The obtained results showed that the use of this device allows reducing the aerodynamic resistance of the cyclone by 14.6%, and for counter-swirling flows’ dust collector (CSFC) by 17.2-23.6%. It was found that meanings of the aerodynamic resistance depend on value the share proportion of the flow entering into lower CSFC apparatus’ input.

Numerical modeling of heat and mass transfer during coffee roasting process

2011 ◽  
Vol 105 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Angelo Fabbri ◽  
Chiara Cevoli ◽  
Laura Alessandrini ◽  
Santina Romani
Keyword(s):  
Mass Transfer ◽  
Numerical Modeling ◽  
Heat And Mass Transfer ◽  
Roasting Process ◽  
Coffee Roasting

An experiment on transient heat and mass transfer in humid air flow

1982 ◽  
Vol 2 (1) ◽  
pp. 3-11 ◽  
Author(s):  
I.Y. Ahmed ◽  
H. Barrow ◽  
S.L. Dixon
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Air Flow ◽  
Humid Air

A T-RANS/VLES Approach to Indoor Climate Simulations

2002 ◽  
Author(s):  
S. Kenjeresˇ ◽  
K. Hanjalic´ ◽  
S. B. Gunarjo
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Large Scale ◽  
Single Point ◽  
Ventilation System ◽  
Convective Motion ◽  
Wall Friction ◽  
Indoor Climate ◽  
Thermal Buoyancy ◽  
Order Of Magnitude

For accurate prediction of flow, scalar transport and wall heat and mass transfer in complex building space we propose a time-dependent RANS (T-RANS) approach which resolves in time and space the large-scale convective motion and associated deterministic eddy structure. The residual (“subscale”) turbulence is modeled by a single-point closure. The method can be regarded as Very Large Eddy Simulations (VLES) since the deterministic and modeled contribution to the turbulence moments are of the same order of magnitude. The modeled part becomes dominant in the near-wall regions where there are no large eddies and the proper choice of the subscale model is especially important for predicting wall friction and heat transfer. We use an ensemble-averaged 〈k〉 - 〈ε〉 - 〈θ2〉 algebraic stress/flux/concentration closure as the subscale model which can provide information about the stress and heat/species flux anisotropies. The method is especially advantageous for predicting flows driven or affected by thermal buoyancy, for which the conventional eddy-viscosity/diffusivity RANS models and gradient transport hypotheses are known to fail even in simple generic configurations. The approach was validated in a series of buoyancy-driven flows for which experimental, DNS and LES data are available. Examples of full-scale application include computational simulations of real occupied and furnished residential or office space in which the furniture elements and persons are treated as passive blocking elements. The simulation showed that the T-RANS approach can be used as a reliable tool for a variety of applications such as optimization of heating and ventilation system, building space insulation, indoor quality, safety measures related to smoke and fire spreading, as well as for accurate wall heat and mass transfer predictions.

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