Fiber Cloth Duct Design Guide

Fabric cloth air ducts can be designed to achieve air delivery effects that traditional air delivery systems cannot achieve through the microscopic holes that open on the surface of the duct wall. The design methods/steps of the fabric cloth air ducts are generally divided into two parts.

Ⅰ. The program design of the fabric cloth air ducts

Fabric cloth air ducts in the program design stage are mainly for drawing design, and the design process can be divided into four steps.

1. Determine the range and control range according to the profile

It is generally in accordance with the principle of average placement to take the middle line of two adjacent fabric cloth air ducts as the boundary. According to the actual engineering situation, the range is divided according to the air volume of the duct and the layout of the plane, so as to achieve uniform distribution of air volume. The height of the comfort zone (the height of the air supply) is selected according to the needs of the application site (refer to the design specifications), and the general comfort air conditioning is selected as 1.5 to 1.7 meters.

2. Determine the direction of the opening

According to the well-divided area, draw the direction of the nozzle jet, and select the number of rows of holes required. Because of the existence of diffraction of the jet, the direction of the jet can not be directed to the boundary line, but to leave 1.5 to 3 meters of diffraction distance. Based on the position of the jet direction line on the already drawn bell scale, the nozzle orientation can be obtained.

3. Determine the air volume distribution

With the determination of the direction of each single tube opening, the number of rows and control range, you can determine the proportion of air volume shot from the nozzle according to the proportion of the area to be covered by each row of nozzles, and marked on the drawing.

4. Determine the infiltration airflow and open-hole airflow according to air volume distribution

According to the actual situation of the site and the special requirements of the application site, Durkee system chooses the fiber with suitable infiltration rate, so as to get the appropriate infiltration flow rate, and then calculate the open-hole flow rate according to the total air volume.

Ⅱ. The design part of the fabric cloth air ducts

The previous scheme design only determines the distribution and orientation of air volume from a macroscopic point of view. But it requires special calculations to achieve it and to determine the size of openings and the number of rows.

And it is in this step that the real technology of that core is done. In fact, the size of the opening is determined by the orifice pressure difference and the outlet air velocity, which in turn is determined by the range, angle, unending air velocity and resistance. The resistance depends on the flow velocity, cross-sectional area and temperature difference, which is a multivariate system of equations. To connect this system of equations, a coefficient value must be available, which varies according to the temperature gradient and velocity gradient, and this determines that such a set of calculation software requires a large database of experimental data to support. The richer the database, the closer the results obtained are to the ideal values. The design software consisting of this database can be used to obtain the number of openings, sizes and rows we need.

This is the reason why fabric cloth air ducts can be designed with micro-perforations on the surface of the duct wall to achieve air supply effects that are not possible with conventional air supply systems.