Abstract:
The objective of this research is to design a blower for use in a mechanical ventilator. First, chose the blower's performance target, namely pressure and flowrate, by researching the requirements of patients, ASTM F 1100-90 standard, and performance of blowers used in ventilator on the market. The blower's performance target was determined to be a static pressure difference of 9,600 Pa and a flowrate of 0.00247 m3/s at 120,000 rpm. The Cordier diagram was then used to determine the diameter of the rotor and the type of turbomachine. It was known that the blower was designed as a centrifugal blower. Following that, the blower geometry was generated and simulated to predict its performance by using the computational fluid dynamic (CFD) program ANSYS FLUENT. Many factors influencing correct solutions are verified by checking results convergence, mesh independent study, and comparing other simulation settings, including compressible flow, and sliding mesh condition. The simulation setting was then validated using a WS7040 blower to predict its performance compared with actual testing and manufacturer data. When comparing simulation results to manufacturing performance data, there is an 8 percent error and an 18 percent error when comparing simulation results to experiment performance data. The simulation was utilized to predict the blower performance after it had been verified and validated. The simulation result showed the blower can generate 10,517 Pa static pressure difference and 0.00247 m3/s flowrate at 120,000 rpm rotational speed. Other flowrates were tested for generating a performance curve of the blower and using Fan's laws to predict performance at different speeds. Finally, the performance curves were compared to the requirements of the patients and the standard, demonstrating that the blower can meet all requirements.