Direction-adjustable air inlet and outlet type jet fan

Abstract

The invention relates to a direction-adjustable air inlet and outlet type jet fan which comprises a shell body, an airflow inlet end, an airflow outlet end and a motor. The shell body is fixed at the inner portion of the top wall of a tunnel through a hanging bracket. The motor is arranged in the shell body. A moving impeller is arranged on a motor shaft. A silencer I and a silencer II are symmetrically and respectively arranged at the front end and the rear end of the shell body. A diversion cone I is arranged at the lower portion of the silencer I. A diversion cone II corresponding to the diversion cone I is arranged at the lower portion of the silencer II. The front end of the silencer I is connected with a guide duct I. The rear end of the silencer II is connected with a guide duct II. The direction-adjustable air inlet and outlet type jet fan has the advantages of being simple in structure, few in airflow losses and low in noise.

Description

technical field [0001] The invention relates to a jet fan, in particular to a variable-direction air inlet and outlet type jet fan. Background technique [0002] Jet fans have been widely used in various road / railway tunnels and other underground tunnel spaces. In actual use, jet fans (including pipe mufflers at both ends) are parallel to the ground, and the fans are installed with ground-fixed Type and top wall hanging type. For the jet fan installed on the top of the tunnel, the center height of the fan installation (that is, the height from the center of the fan to the top of the tunnel) will have a great influence on the actual thrust of the fan. Here, a fan installation coefficient K is introduced. If If the center height of the fan is too low, part of the airflow at the fan outlet will be lost due to friction with the tunnel wall. The detailed coefficient K value is shown in the attached figure 1 shown. [0003] At present, in the process of actual engineering use, ...

AI Technical Summary

Problems solved by technology

From attached figure 2 It can be seen from the figure that when the ordinary linear jet fan is in use, a vortex area of ​​a certain size is likely to be generated outside the effective airflow area of ​​the inlet and outlet, resulting in an additional loss of the airflow of the fan (about 20%). Additional noise (about 2.5dB) will be generated, making the efficiency of the fan in actual use far lower than the test results in the standard laboratory

In the end, the air volume and thrust required by the jet cannot be satisfied, and the noise is likely to exceed the standard

Therefore, such fans generally have the phenomenon of high energy consumption, high noise and low efficiency.

[0004] Although there is currently a company in the world that has launched a banana-shaped jet fan (Banana Jet) as early as a few years ago, the banana-shaped jet fan is directly inclined downward with the tunnel axis through the complex special-shaped pipe muffler before and after the fan body. 1. The outlet changes the direction of the air flow, but at the same time it destroys the flow field before and after the impeller, because the standard fan must have a straight section ≥ 1.5 times the diameter of the length in order to ensure the good airflow layout conditions of the inlet and outlet flow fields of the fan. Otherwise, there will be secondary vortex inside the fan, and the air inlet and outlet efficiency will deteriorate sharply.

Moreover, due to the heavy weight of the muffler itself, and because the muffler is usually a cantilever installation structure, the force of this downward-sloping structure is very complicated, and the connection between the muffler and the fan body must be designed to be very complicated and heavy. In order to ensure a certain degree of safety, therefore, regardless of the use of the inlet and outlet airflow to change direction, compared with the ordinary linear jet fan, the structural safety and internal flow field rationality of the fan with this structure are insufficient, so in the actual project not used much

[0005] At the same time, some people in China have designed a follow-up jet fan that can swing freely in the direction of airflow. Solved, but the machine is too complicated, and the limit is also a problem when the fan is running, so its reliability and safety are not enough

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