The Optimized Design Of Cross-flow Fans Based On The CFD Analysis

With the advance of standard of living and the renovate of consume concept, the technical indexes, like noise, flow rate, and efficiency for cross flow fans which are installed inside family house, receive great attention in the design. The design of cross flow fans mainly depends on experimental data, and the cost of design is expensive, because the existence of the eccentric vortex inside the fan results in the inapplicability of similarity method which is widely used in field of fan design. In this paper the inner flow field of cross flow fans is simulated by a commercial CFD software, and the aeroacoustic noise is forecasted by the Ffowcs Williams-Hawkings equation, the character parameters of cross flow fans affecting the performance are researched, the aim is to optimize the design of cross flow fans based on the flow mate and noise. Alternatively, designing the fan model with computational fluid dynamic method can provides computational results in guiding the design and helps us to economically achieve the optimum design. The particular works contain three aspects:First, based on the configuration character of cross flow fans model, a parameterized modeling program was developed. By the parameterized modeling program, many kinds of cross flow fans and grid could be generated quickly, which helps to avoid repeating work and helps to decline the time and money for design.Second, three-dimensional models of cross flow fans are simulated by the commercial CFD software---Fluent. Based on the deeply analyzed and discussed results, the inner flow characters of cross flow fans are found. The aeroacoustic noise is forecasted by the Ffowcs Williams-Hawkings equation, and the discrete tonal noise spectra of the uniform and random pitch fans are analyzed. The aim is to validate the rationality of this method.Finally, according to methods mentioned above, the change of character parameters affecting performance are investigated, such as volute throat clearance, external angle, internal angle, diameter ratio and rotational speed. And based on the flow mate and aeroacoustic noise, the original configuration parameters are optimized.