| 摘要 |
PROBLEM TO BE SOLVED: To reduce the noise level and also the noise level on the low frequency side to solve the discomfort by arranging a number of blades in the peripheral direction at intervals determined on the basis of a logistic map. SOLUTION: An air filter 6, a heat exchanger 2 and the like are mounted on a ventilating passage 5 connecting an intake port 1a and a blowout port 1b. The blades 12 of a cross flow fan 11 are formed by arranging a plurality of supporting discs 13 along a rotary shaft 14 of the fan 11, and mounting a plurality of blades 12 around the supporting discs 13 while surrounding the rotary shaft. An interval between the blades in adjacent to one another in the peripheral direction is determined on the basis of the chaos theory. Concretely, an angle made by an n-th blade 12 and a (n+1)-th blade 12 on the rotary shaft 14 is determined by determining the chaos sequence as a pseudo-random number corresponding to each blade 12 on the basis of the logistic function, and applying the same in a specific expression, when the total number of blades 12 is B. |
