Gas atoms or molecules act almost independently of each other in comparison to liquids or solids, particles of which have greater correlation. The effects of different combinations of air velocities and temperatures on growing and A relationship between the animal reactions and a chill factor (a direct. weanling pigs to various air velocities and temperatures. The chambers are designed The assessment of thermal environment in relation to pig production.
Its capacity was kJ h The evaporator was made of copper pipes and outside surface covered with aluminium plates. An axial ventilator was located on the back of the evaporator to distribute the cooled air into the cold store.
An electrical heater was used to defrost. The capacity of evaporator was kJ h The fan speed was rpm. The ventilator has four vanes. Schematic view of the experimental cold store dimensions in mm Sensors: Velocity measurement device was vane type. Measurement limits of the air velocity sensors ranged between 0 and 20 m s Cold store was empty during the experiments. Cooling system was worked.
A special framework was made of iron to replace sensors on it.
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Four temperature sensors were used to determine ambient temperature. A vane type air velocity measurement device was used in this research.
Measurement points in cold store First of all, cold air velocities were measured for determined point in the cold store. Measurements were realized in top, medium and bottom level of the cold store Fig. Mean, maximum, minimum, standard deviation and coefficient of variation were calculated for these data. The results were used to produce spatial distribution maps of air velocity. Surfer Graphic Program was used to create maps. Measured data arranged in a file to use by Surfer Program.
Grid data files were created by using original data files.
Then these grid data files were used to create contour maps by using Surfer Graphic Programme. For example mean of air velocity was changed between 0.
Effect of Air Velocity on Temperature in Experimental Cold Store
General CV was In addition, there were also differences for the same levels of the cold store. Coefficient of variation was Changing of the air velocity was small for the medium level of the cold store but velocities of the cold air was also small.
Distribution of the air velocity in the experimental cold store is shown in Fig. The evaporator was mounted on the ceiling of the cold store. In front of the evaporator, velocity of the air was higher than that left and right areas of the evaporator for the top level in the cold store. Air velocities in the cold store Fig.
Distribution of air velocity in the experimental cold store Table 1: Descriptive statistics of air velocity distribution Table 2: There is no big difference between middle and bottom level of the cold store.
The results of the air velocity were not good for these levels because of the evaporator. These explanations can also be seen on the spatial distribution maps Fig.Lesson 5.2.2 - Temperature, Air Pressure, and Humidity
Ambient temperature distribution in the experimental cold store Coefficient of variations of top, middle and bottom level at the cold store were Coefficient of variation for all data was Smallest temperature in this experiment was measured around the evaporator. Temperatures of the other areas were higher than these values. Air circulation produced by evaporator was caused for these results Fig.
Reason of bad spatial distribution of air velocity is evaporator fan.
Basics of Air Velocity, Pressure and Flow
Evaporator fan is not enough to circulate air inside cold store and to create homogenize air distribution. Evaporator was selected for this experimental cold store according to the calculations. Additional fan or fans may be used to improve distribution of the air velocity for this cold store. Bad air distribution affects spatial distribution of the ambient temperature. Ambient temperature differences may be arranged by good air distribution.
Bad distribution area for air velocity can be determined by using these maps. If it is required, ventilation of the air can be directed to the bad distribution area or added new ventilation units to correct bad distributions of these factors in a cold store. Pressure Measurement Application Note: Basics of Air Velocity, Pressure and Flow Air velocity can be measured by sensing the pressure produced by the movement of the air.
This application note will describe the basic relationships between air velocity and the pressure generated by air flow. Anyone who has put their hand out the window of a moving car has experienced the force applied by moving air.
The figure below shows how this might look. The tube that is placed into the air stream is called a pitot tube after Henri Pitot, the French engineer of the early 18th century who invented it. As the velocity of the air increases the pressure also increases inside the pitot tube with respect to the ambient atmosphere.
Note that the pitot must be pointed directly into the flow — if the tube is mounted at some angle to the direction of flow, the transducer will not sense the full pressure developed by the air velocity. The pressure developed by the air velocity is called the velocity head, and it is affected by the density of the air. The density of the air, in turn, is a function of the local atmospheric pressure and the temperature.
The equations that relate all these factors are: Note that to determine the air velocity the density must first be known. This is the second equation and relates ambient atmospheric pressure and temperature to density.