Proceedings of the 7th International Symposium on Cavitation
巻, 号, ページ
No. 61
pp. 1-11
出版年月
2009年8月
出版者
和文:
英文:
会議名称
和文:
英文:
The 7th International Symposium on Cavitation
開催地
和文:
英文:
Ann Arbor, Michigan, USA
アブストラクト
Cavitation around a plano-convex hydrofoil has been
observed using a cryogenic cavitation tunnel of a blowdown
type. An approximately 300mm long test section with flow
visualization was set between the 100L upper and lower tanks.
The working fluids were water and liquid nitrogen.
Experiments with emphasis on periodical shedding of cloud
cavitation were performed for three channels, 20, 30 and 60
mm in width, and two hydrofoils, 20 and 60mm in chord length
LC. Inlet velocity uin and cavitation number σ were varied
between 3.8 and 19.5 m/sec, and −1.83 and 19.35, respectively.
Incident angle was fixed at 8º. Observed cavitation patterns are
sorted according to the maximum cavitation length Lmax
compared to LC. Type X is defined as no cavitation, type A as
0<Lmax≤LC, type B as LC<Lmax≤2LC, and type C as Lmax>2LC.
Type B has either the periodical shedding mode or the steady
mode, so type PB is defined as type B with periodical shedding
and type SB as type B under steady condition. Apparently types
A and C are almost steady. Type PB solely occurs in the case
that Lmax is comparable to LC. The cavitation patterns are
mapped in the diagram of the degree of subcooling Pin−Psat
versus the dynamic pressure ρuin2/2 because they are not
organized only by σ =(Pin−Psat )/(ρuin2/2). It is suggested that
the maximum cavitation thickness is controlled by the
similarity laws of hydrofoils for types SB and C.
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