scholarly journals Aeration of the premises of the dairy cows keeping in the light weight design in the warm period of the year

2020 ◽  
pp. 45-47
Author(s):  
Darya Viktorovna Abramkina
Keyword(s):  
Dairy Cows ◽  
Flow Rate ◽  
Significant Contribution ◽  
Air Flow ◽  
Warm Period ◽  
Light Weight ◽  
Exchange Flow ◽  
Weight Design ◽  
Flow Through ◽  
Air Exchange

The purpose of the article is to conduct multivariate calculations of aeration in a building at dairy cows keeping in order to identify the most effective way of ensuring normal air exchange in the stall house. According to the results of studies, it was found out that the supply air flow through the external gate makes a significant contribution to the overall air exchange of the stall house. Keywords: aeration; cowshed; ventilation; air exchange; flow rate.

Buoyancy-Driven Exchange Flow Through Small Openings in Horizontal Partitions

1988 ◽  
Vol 110 (4a) ◽  
pp. 885-893 ◽  
Author(s):  
M. Epstein
Keyword(s):  
Flow Rate ◽  
Countercurrent Flow ◽  
Exchange Flow ◽  
Flow Measurements ◽  
Rate Versus ◽  
Single Opening ◽  
Flow Through ◽  
Horizontal Partition ◽  
Flow Configurations ◽  
Universal Correlation

This paper describes an experimental study of the phenomenon of buoyancy-driven exchange (countercurrent) flow through openings in a horizontal partition. A density-driven exchange flow was obtained by using brine above the partition and fresh water below the partition. In the first part of the study, flow measurements were made with a single opening, for opening ratios L/D in the range 0.01 to 10.0, where L and D are the length of the opening (in the direction normal to the partition) and the diameter of the opening, respectively. Four different flow regimes are identified as L/D is increased through this range. As a result of the competition between two of these regimes, the exchange flow rate versus L/D relation exhibits a peak. The exchange flow rate was found, for all practical purposes, to be independent of viscosity, enabling a universal correlation between Froude number (dimensionless exchange flow rate) and L/D. The second part of the study was an experimental investigation of the same phenomenon, but with two openings in the horizontal partition. Two openings were observed to give rise to three different flow configurations involving both one-way and countercurrent flows within the openings.

scholarly journals Evaluation of the possibility of application of slit ventilation of a lightweight cowshed in the warm period of the year

2021 ◽  
pp. 68-70
Author(s):  
Darya Viktorovna Abramkina
Keyword(s):  
Carbon Dioxide ◽  
Air Flow ◽  
Warm Season ◽  
Warm Period ◽  
Opening Angle ◽  
Flow Rates ◽  
Excess Heat ◽  
Air Exchange

The article presents a method for determining the required air exchange for the assimilation of excess heat, moisture release and carbon dioxide input from animals. The results of multivariate calculations of air flow rates at different angles of opening of gravity vent in the warm season are presented. It was found out that when performing slot ventilation with a sash opening angle of less than 5?, it is impossible to effectively remove excess heat in the room.

scholarly journals Side-leakage of face mask

2021 ◽  
Vol 44 (6) ◽  
Author(s):  
B. N. J. Persson
Keyword(s):  
Porous Material ◽  
Air Flow ◽  
External Environment ◽  
Face Mask ◽  
Model Study ◽  
Human Lungs ◽  
The Face ◽  
Flow Through ◽  
Air Exchange

Abstract Face masks are used to trap particles (or fluid drops) in a porous material (filter) in order to avoid or reduce the transfer of particles between the human lungs (or mouth and nose) and the external environment. The air exchange between the lungs and the environment is assumed to occur through the face mask filter. However, if the resistance to air flow through the filter is high some air (and accompanied particles) will leak through the filter-skin interface. In this paper I will present a model study of the side-leakage problem. Graphicabstract

scholarly journals Analysis of the influence of selected factors on natural greenhouse ventilation

2018 ◽  
Vol 49 ◽  
pp. 00036
Author(s):  
Sławomir Grabarczyk
Keyword(s):  
Wind Speed ◽  
Natural Ventilation ◽  
Air Flow ◽  
Leeward Side ◽  
Air Exchange Rate ◽  
Solar Radiation Intensity ◽  
Thermal Screen ◽  
Flow Through ◽  
American Society ◽  
Air Exchange

In greenhouses, in order to maintain proper indoor air temperature, during the period of high values of solar radiation intensity, shading treatments using thermal screens and ventilation are applied. The research was carried out in a mono-span greenhouse in order to determine the effectiveness of natural ventilation. The object of analysis is a greenhouse with a thermal screen installed inside. The tests were carried out during the summer days. The effect of the research was to determine the ventilation air flow through the vents of the greenhouse on the basis of measurements and calculation analyzes. The dependence of the air flow on the windward and leeward side was determined from the wind speed and the temperature difference between the indoor and outdoor air. On the basis of calculations made from observation during shading of the cultivated area and with open ventilators, the coefficients of air exchange per unit floor area of the greenhouse were determined. It was established that at a wind speed exceeding 0.8 m/s, the air exchange rate in the tested greenhouse exceeds the value recommended by the American Society of Agricultural Engineers of 0.04 m3/(s.m2).

scholarly journals Helium-Air Exchange Flow through an Opening with a Partition.

1993 ◽  
Vol 59 (566) ◽  
pp. 3106-3112
Author(s):  
Tae-il Kang ◽  
Koji Okamoto ◽  
Haruki Madarame ◽  
Motoo Fumizawa
Keyword(s):  
Exchange Flow ◽  
Flow Through ◽  
Air Exchange

scholarly journals Fluid mechanical valving of air flow in bird lungs

1988 ◽  
Vol 136 (1) ◽  
pp. 1-12 ◽  
Author(s):  
D. O. Kuethe
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Pressure Difference ◽  
Air Flow ◽  
Low Pressure ◽  
Physical Models ◽  
Unidirectional Flow ◽  
Air Sacs ◽  
Caudal Portion ◽  
Flow Through

The unidirectional flow through the gas-exchanging bronchi of bird lungs is known to be effected by (1) the structure of the major bronchi and (2) a pressure difference between the cranial and caudal air sacs. To study the effects of bronchial structure, simple physical models of bird lungs were constructed. They suggested that, to achieve unidirectional flow, air in the caudal portion of the primary bronchus must be directed towards the orifices of the mediodorsal bronchi. To study the effect of air sac pressures, a controllable pressure difference was produced between the air sac orifices of fixed duck lungs. The cranial orifices had a higher pressure than the caudal ones during inhalation and vice versa during exhalation. There was a set of pressure differences for which the paleopulmo received the same flow rate during inhalation as during exhalation. High pressure differences caused more flow in the paleopulmo during exhalation than during inhalation; low pressure differences had the converse effect.

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