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1. How to calculate the installation of flow meter diameter reduction
1. Flow rate, viscosity, diameter reduction hole thickness, and section ratio were obtained to obtain the internal flow field variation laws under different simulation conditions, and numerical simulation calculations were also used.
2、 A flowmeter, also known as a flow meter, measures the instantaneous flow rate and cumulative volume of a liquid, and can also quantitatively control the liquid. It has the characteristics of high accuracy, long service life, and easy operation and maintenance.
2. Why is the flow meter on the air conditioning duct smaller than the main duct?
It is a normal design phenomenon for the flow meter on the air conditioning duct to be smaller than the main duct, mainly due to measurement principles, installation specifications, and system requirements, rather than faults. The specific reasons are as follows:
1. Adaptation requirements determined by measurement principles.
Flow rate adaptation: The flowmeter needs to ensure accuracy within a specific flow rate range (usually 1-5m/s). The main pipeline diameter is large and the flow rate is slow (such as the flow rate of the main pipeline of a large flow central air conditioning system may be lower than 1m/s). Reducing the pipe diameter can increase the local flow rate to the optimal measurement range2. Pressure loss control: If the diameter of the flowmeter is the same as that of the main pipeline, the pressure loss of the large diameter flowmeter will increase sharply with the increase of flow rate. Reducing the pipe diameter can distribute the pressure loss reasonably through the reduction section (such as the Bilu Ventur
2. Mandatory Requirements for Installation Specifications 1 Industry standard for reduced diameter installation: According to the "Design Code for Heating, Ventilation and Air Conditioning" (GB50019) and the technical manual of the flowmeter manufacturer, when the flow rate of the main pipeline is lower than the minimum working flow rate of the flowmeter, reduced diameter installation (usually with a reduction ratio of 0.5-0.8) is required to ensure stable measurement signals. 2. Requirements for straight pipe section: There should be sufficient straight pipe sections before and after the flowmeter (generally 10D in the front and 5D in the back, where D is the diameter of the flowmeter). Reduced diameter can reduce the occupation of space in the main pipeline while meeting the requirements of the straight pipe section.
III. Pingzu Huixun Balance of System Cost and Accuracy 1 Cost control: Large diameter flow meters (such as DN200 and above) are priced 3-5 times higher than small diameter flow meters of the same precision. Reducing the diameter installation can reduce equipment costs, and the reduced diameter section is easy to manufacture and has low construction difficulty. 2. Accuracy guarantee: Small diameter flow meters have higher relative accuracy (such as DN50 vortex flow meters with an accuracy of ± 1%, DN200 flow meters with an accuracy of only ± 2%), and the measurement accuracy is more stable after reducing the diameter, especially suitable for variable flow conditions in air conditioning systems.
IV. Common Types of Adaptation Cases 1 Vortex flowmeter: commonly used in air conditioning water systems. When the flow rate of