Tip clearance

About: Tip clearance is a research topic. Over the lifetime, 2637 publications have been published within this topic receiving 32671 citations.

An 11-stage axial compressor performance simulation considering the change of tip clearance in different operating conditions

Abstract: The multistage axial compressor is one of the critical components of aero-engines and plays a key role in their performance, reliability, and economy. Tip clearance has a significant impact on the performance and stability of multistage axial compressors. Due to blade and disk deformations, tip clearance will vary significantly in different operating conditions. Thus, tip clearance should be accurately estimated when evaluating compressor performance. This paper proposes a new model to predict changes of tip clearance of multistage axial compressors in different operating conditions. A first-principles approach is used to estimate the change of tip clearance caused by thermal and mechanical deformation. The span-wise temperature distribution across each stage of the multistage compressors is considered by the proposed model in this paper. The model was validated by General Electric Company (GE) E3 engine experimental results. Using the model, the performance of an 11-stage axial compressor is simulated. T...

An enhanced Greitzer compressor model with pipeline dynamics included

Abstract: The modeling of a centrifugal compressor system with exhaust piping acoustics is presented in this paper. For a centrifugal compressor test rig with modular inlet and exhaust piping, a mathematical model is derived based on the Greitzer compression system model. In order to include the dynamics of the piping acoustics, a transmission line model is added to the original compressor equations, and different compressor-piping configurations are tested. The simulation of the resulting mathematical models of the compression system are compared to the measured response. Employing active magnetic bearings to perturb the axial impeller tip clearance of the compressor, the compression system is excited over a wide frequency range and the input-output response from the impeller disturbance to the plenum pressure rise is analyzed. A good agreement is observed between the experimental and theoretical Bode plots.

Shroud means for turbine rotor blade tip clearance control

Abstract: A hot gas turbine wheel shroud ring, for hot gas turbine engines, is adapted to be concentrically positioned around the periphery of a row of buckets or blades on the circumference of a turbine wheel to provide a predetermined small sealing and running clearance between the tips of the turbine blades and the ring. The shroud ring is characterized as incorporating certain opposite warping or deflection characteristics from those found in shroud rings under normal high temperature operating conditions.

Recirculation casing treatment by using a vaned passage for a transonic axial-flow compressor

Abstract: The tip leakage flow has an important influence on compressor performance particularly for the case of transonic compressors. Recirculation casing treatment is an effective approach to control the tip clearance flow which results in stability enhancement. Numerical simulations for a high-speed axial-flow compressor rotor with endwall recirculation, applying a state of the art design for the recirculation passageway are presented in the current study. Anti-swirl vanes are placed in the recirculation passageway. The effects of recirculation casing treatment on the compressor overall characteristics, stability, blade loading, and flow field are presented and discussed. Results show a significant range extension with a very small penalty in efficiency. Besides, the recirculated mass flow is only a few per cent of the main flowrate.

Local Mass and Heat Transfer on a Turbine Blade Tip

Abstract: Local mass and heat transfer measurements on a simulated high-pressure turbine blade-tip surface are conducted in a linear cascade with a nonmoving tip endwall, using a naphthalene sublimation technique. The effects of tip clearance (0.86–6.90% of chord) are investigated at various exit Reynolds numbers (4–7 × 105) and turbulence intensities (0.2 and 12.0%).