Matching calculation method for centrifugal impeller and diffuser under pre-swirl air intake condition

Abstract

The invention discloses a matching calculation method for a centrifugal impeller and a diffuser under a pre-swirl air intake condition. The method comprises the steps of giving air medium characteristic parameters including an adiabatic exponent and a gas constant; giving centrifugal impeller design parameters including a centrifugal impeller inlet pre-swirl angle, a centrifugal impeller inlet wheel cap relative axial airflow angle, a centrifugal impeller inlet wheel cap relative Mach number and a total pressure ratio; calculating normalized diffuser blockage flow; calculating normalized diffuser blockage flow; calculating a ratio of a diffuser blockage throat area to a centrifugal impeller blockage throat area when the centrifugal impeller is completely matched with the diffuser; giving centrifugal impeller inlet total parameters including an inlet total temperature, an inlet total pressure and given designed blockage flow; calculating centrifugal impeller inlet total density and inlet stagnation sound velocity; calculating the diffuser blockage throat area when the centrifugal impeller is completely matched with the diffuser; and calculating a change law of the centrifugal impeller blockage throat area along with a flow position when the centrifugal impeller is completely matched with the diffuser. A centrifugal air compressor manufactured by the method has higher isentropicefficiency and a wider stable working condition range.

Description

Technical field [0001] The invention relates to a design of the flow channel area of ​​a centrifugal compressor. In particular, it relates to a calculation method for matching a centrifugal impeller and a diffuser under pre-swirl air intake. Background technique [0002] Centrifugal compressors are widely used in aero engines, ground gas turbines, automotive and marine turbochargers, petrochemical compressors, and play an irreplaceable role in national defense, civil industry and other fields. The core components of a centrifugal compressor include a centrifugal impeller, a diffuser, etc. The design methods of each individual component are becoming more mature and the design results are satisfactory, but there are few studies on the matching of the centrifugal impeller and the diffuser. Practical experience shows that a single impeller has a higher efficiency and pressure ratio and a wide range of stable operating conditions. Once matched with a diffuser, its efficiency and pres...

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Problems solved by technology

The above research results are only for the specific situation of axial intake, and there is no relevant report on the matching of centrifugal impeller and diffuser under the condition of any pre-swirl intake angle (including axial intake)

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