摘要: An experi ment was conducted to measure the breakup lengths of water jets with a high-speed video camera for Weber numbers from0 to about 1.1×103.The initial jet diameters are changed from0.3 mmto 1. 0 mm.The results indicate that at lowjet velocity the breakup lengths of the jets are increased linearly from 0 to a maxi mumvalue.At the Weber number about 20 the breakup length of the jet reaches its maxi mum value for different initial jet diameter.Acomputation based onthe dispersion equationis conducted to study the relationship between the growth rate of the jet surface wave and the maxi mumbreakup length.The computations showthat the maxi mumgrowth rate for the axisymmetric surface wave has a turning point at Weber number about 20, and that agrees well with the experi ments.
摘要: An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick, stacking line andinlet angle using a 3Dapproach, with a significant efficiencyi mprovement at the design point.The off-design behavior of this new compressor is also checked afterwards, which shows that the whole performance of the inlet stage is improved over a wide range of mass flow.The losses are reduced, proving the good performance of the opti mum.The whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.