The design of the cooling fan
the design of the cooling fan first measured the air volume and air pressure, the relationship between measuring the characteristics of air flow is very difficult, there are two ways of method used to measure the static pressure and air volume, one for the wind tunnel test, another way for the box. Air volume and static pressure feature specification is double box method is used to measure, the variable air exhaust system using double box method to adjust the air density, moment to open the nozzle will cause instantaneous changes of the static pressure and air volume, and then reads each hydrostatic pressure reading on the meter.
in the operation of the standard atmosphere and fixed voltage and frequency under the condition of static pressure in air volume for the performance of function. Static efficiency of a cooling fan is equal to the volume of air volume multiplied by the static pressure divided by the input of electricity. A cooling fan is including motor, fan and casing outside, so its efficiency including motor of motor efficiency, as well as blade and casing outside air flow efficiency.
all the system impedance/cooling fan system characteristic curve of air flow, air flow in the flow path can meet system internal parts, the impedance will limit the free flow of air. The change of pressure is measured by static pressure, expressed in inches of water column. Each tank platoon in order to confirm the wattage, cooling system design or manufacturer must have not only effective cooling fan fan characteristic curve to determine the maximum air volume, and must know wind resistance curve of the system. System of internal parts can cause the loss of air pressure. The loss due to the air volume change, known as the system impedance.
in addition, the cooling fan system operating point are characteristic of the fan characteristic curve and the intersection point, called the system operating point, the working point is the optimal operation point of the cooling fan. In working point, the cooling fan is the change of the slope to a minimum, and the system characteristic curve of the lowest rate. Note that at this time of the cooling fan static efficiency ( Airflow by air pressure present electricity) For the optimization.
the design step of cooling fan will be here to share, in addition, we also pay attention to keep the air in the design of flow is not blocked, as far as possible into the outlet tuyere and unblocked, cooling fan of guide vertical airflow through the system, to ensure that the air flow is smooth and enhance cooling efficiency.