Investigation of the effect of lateral blade angle on fan characteristics in radial fans

Fans, which are turbomachines that transmit air or gases from their location to the desired location, are classified according to the direction of fluid transmission. Fans, which are widely used in tunnel and car park ventilation, smoke evacuation, power plants, industrial ventilation, HVAC systems and many other areas, are driven by electric motors, so their energy consumption is quite high in proportion to their area of use. For this reason, efficient use of energy can be achieved by making design changes according to the purpose of use. In some usage areas of radial fans, whose main task is to pressurize the fluid, speed increase may be preferred instead of pressure increase. In this case, the fan blades are given a lateral angle. Fans with lateral blade angles, which are used in areas such as road sweeper, source ventilation and boiler flue fans, contribute to the reduction of bearing forces in addition to flow performance. The lack of academic studies on this type was identified in our literature search. In this study, the effect of the lateral blade angle on the radial fan performance was investigated. The study consists of two parts as experimental and computational fluid dynamics (CFD) analyses. First of all, the characteristics of a radial fan without lateral blade angle were obtained by experimental investigation. For this purpose, after setting up the experimental setup in accordance with the AMCA 210 standard, measurements were made in accordance with the standard. These measurements were made once again by canceling the corrective element in the standard, and the experimental phase was completed. In the second stage, the modeling of the experimentally investigated fan was made. The existing fan design was completed with computer aided design. Experimental results were obtained with an error margin of less than 5% by repeating the experimental conditions using computational fluid dynamics. In CFD analysis, k-ω (omega) SST turbulence model and SIMPLE solution method were used. In the last stage, different lateral angles were given to the fan blades and new identical experimental setup solid models were obtained, and the performance of fans with different lateral blade angles was investigated by CFD analysis under the same conditions. In fans with lateral blade angles examined in both directions and at different angles, fan wheels with lateral blade angles at different angles up to -25 degrees could be designed due to design and manufacturability limits. It has been observed that the characteristics of all radial fans with lateral blade angles are more inefficient in terms of pressure than full radial fans. It has been observed that in this type of fans, there is a loss in increasing the pressure of the fluid, but thanks to this loss, the fluid can reach higher speeds. In this study, it has been determined that the most efficient angle in radial fans with lateral blade angle is 20 degrees in the negative (counterclockwise) direction. Key words: Fans, Radial Fan, Blade Angle and Fan Characteristics