Design resistance balance of ventilation duct
1、 The ventilation duct in the ventilation system is an interconnected whole, which must follow the resistance balance law of each branch. Once the structural form and pipe size of the air duct system are determined, under the action of a certain fan, the air volume of each section is automatically distributed according to the resistance balance law. If the resistance balance calculation is not carried out in the design calculation, the actual air volume distribution of the system will be inconsistent with the design. Of course, we can also adjust the air valve to distribute the air volume, but in this way, the air pressure of the non adverse loop is redundant. Therefore, it is of practical significance to consider the resistance balance of each loop in the design and calculation.
However, in the process of hydraulic calculation and resistance balance of air duct, many designers only rely on empirical estimation or manual calculation by looking up drawings, which is time-consuming and laborious and can not achieve the ideal effect. The calculation software designed by the author takes excel as the working platform and VBA as the development tool, so as to ensure the execution efficiency of the program.
2、 Basic steps of resistance automatic balance calculation
The execution process of automatic calculation of resistance balance of air duct system basically follows the calculation steps of conventional design, mainly as follows:
① Input and save the logical relationship between nodes and relevant parameters of pipe sections in turn, and then preliminarily select the assumed wind speed of each pipe section according to the technical requirements;
② Automatically calculate the equivalent hydraulic diameter and resistance loss of the pipe section according to the assumed wind speed;
③ The node reverse search method is used to automatically find the path and resistance loss of each loop of the system, and determine the unfavorable loop of the system;
④ Automatic resistance balancing for non adverse loops.
⑤ Check the calculation results.
In the above process, only the workload is small, ① and ⑤ need manual intervention, while other steps are completed automatically by the computer. Thus, it can not only ensure the calculation speed and accuracy, but also make appropriate manual adjustment according to the needs.
The above is the detailed introduction of Jinan ventilation duct. I hope it will be helpful to you If you have any questions, please contact us We will provide you with professional service http://cqlej.com