Passive control strategy for flow quality of linear cascade wind tunnel
To improve the flow quality of linear cascade tests with high-loading blade sections and ensure the reliability and accuracy of test data,the evaluation parameters of flow quality of linear cascade were established,and two passive control schemes of intermediate streamlined upper end-wall and its coupling with outlet adjustable tailboards were proposed.The control strategies of the above two schemes on the flow quality of high-loading linear cascade were studied by numerical simulation method verified by experiments.The results showed that both schemes can effectively suppress the deterioration of flow field near the upper end-wall area,thus improving the inflow accuracy,flow periodicity and two-dimensionality of cascade.When the set angle and gap of the upper end-wall and the tailboard angle matched the ideal intermediate streamline of cascade,the two schemes presented the best improvement on the flow quality.The scheme of intermediate streamlined end-wall combined outlet tailboards was superior to the intermediate streamlined end-wall scheme,such that the inlet Mach number deviation of the central three blade passages was less than±0.005,and the incidence angle was less than±0.3°.And the periodicity deviation of inlet and outlet Mach numbers shall not exceed 0.005,and the periodicity deviation of inlet and outlet flow angles shall not exceed 0.3°.The axial velocity density ratio(AVDR)of cascade was 1.1 at the incidence angle of 0°.The two control schemes showed good applicability to the flow quality adjustment of cascade at high incidence angle.
linear cascade testend-wall modificationtailboardsflow qualityaccuracyperiodicity
NETL
NSTL
万方数据
