The effects of blade angles on the performance of regenerative blowers Essay

II. Introduction
Regenerative blowers are used generally in many extensive ranges of utilization. These include pneumatic conveying, sewage aeration, aquaculture aeration, vacuum packaging, vacuum lifting, packaging equipment, printing presses, spas, dryers, dust and smoke removal, industrial vacuum system, chip removal for engraving equipment, and soil vapor extraction. Regenerative blowers are considered an optimal solution as a suitably blower that will give long term service for complimentary operation if the system requires large amount of airflow and low pressure. It is very used in our today's industry even though the efficiency of regenerative blowers is not that great, approximately less than 50 percent. The effects of blade angles on the performance of regenerative blower has been previously studied theoretically, numerically, and experimentally by previous researchers but out of all of them, none has thought about anything related to twisted blades. One researcher, Yukio Yamita, has studied the regenerative pump performance using only three vane angles which are 60o, 90o, and 120o combined with six impeller diameters ranging from 90 mm to 180 mm. It has been determined that the impact of the impeller diameter on the work diversify with van angle. Another researcher, Badami, reviewed the weight of vane inclination on the work of regenerative pump, where 11 angles ranging from 45 degrees up to 135 degrees were studied theoretically and experimentally.
These studies did not consider experimentally the impact of inlet blades angle on the performance of regenerative blowers. This study highly depends on experimental study of the effect of changing the inlet flow angle for the blade profile that varies from the hub to the tip to the impeller on the performance of regenerative blower.
Theoretically and numerically, a lot of researchers has already research on various effect of different blade angles and blade shape on the effectiveness of regenerative blower and pump by using computational fluid dynamics analysis. Two researchers, Meakhail and Park, used computational fluid dynamics to show that the flow go in the impeller from the blade side which is about sixty five percent of the said area and departing from the blade tip and blade side which is about the remaining thirty five percent of the blade side area. The analysis can be seen on the figure below.
Figure 1
The two researcher based their mathematical model on this observation which will handles one inlet angle and two exit angles for the impeller blades of regenerative pump. They also modified this model to be more suitable when using regenerative blower to be investigated experimentally and numerically by the software CFX-ANSYS 16.1.
In conclusion, a regenerative blower system in this study is constructed in such a way that the four impellers with different inlet flow angles which are 90 degrees, 115 degrees, 125 degrees, and 135 degrees will be manufactured just like what is shown in figure below.
The author of this study is successful on validating the theoretical and numerical investigation with the experimental results of the impact of inlet blade angle on the work of regenerative blower.