Linear Cascade Test Rig

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The test facility is a 12 meters long wind tunnel used for the testing of turbo machinery blades. The blades are fixed in a linear cascade at the outlet. This makes it possible to study their performance and to make detailed measurements. A probe may be placed in the front and at the back of the blades to examine the pressures and the angles of the airflow. In this way a picture of how the air stream is moving between the blades can be obtained and the performance curves and loss can be calculated.

The test facility is divided into five sections: Inlet, fan assembly, diffuser, settling chamber and test section. The fan assembly is made of two contra rotating fans. They are placed between two attenuators in order to reduce the noise. Electrical three-face motors move the fans. Adjusting the frequency of a converter controls the speed of the fans.

The settling chamber holds three metal grids and a honeycomb section. This section is supposed to establish a higher pressure in order to make the flow more uniform and reduce vortices. At the end of the settling chamber is a contraction. It is aimed to reduce the influence of the wall friction, in due to have an approximately ideal flow.

The test section is where the blade cascade is placed. It is possible to rotate this section in order to change the incidence angle of the flow to the blades. Two probe carriers are mounted respectively in the front and at the back of the cascade. They can move the probe horizontally and vertically in the outlet with electrical motors.