# A New Influence Mechanism of Clocking Effect in Subsonic Compressor
###### Abstract  
This paper investigates the clocking effect in subsonic compressor element stages and the influence of design parameters on the flow mechanism. We focus on the relationship between the wake-induced separation loss and wake mixing loss and the unsteady mechanism in the wake flow process without considering the transition through several steady and unsteady numerical simulations aimed at a series of subsonic compressor element stages. The simulation results indicate that the performance difference at various indexing positions depends on the relationship between wake mixing loss and wake-induced separation loss for different compressor designs and operating conditions. Furthermore, the pressure transport caused by the negative jet of the stator 0 wake in Rotor 1 creates a local acceleration region called SFAF, and a decrease in its absolute flow angle reduces the stator 1 separation. Sufficient rim work of the rotor at highly loaded operating conditions is the basis for generating an effective SFAF. Furthermore, the fore-loading blade of Rotor 1 significantly reduces suction surface pressure drop, and a small angle between the stagger angles of Stator 0 and Rotor 1 increases the unsteady rotor load caused by the upstream wake to the total rotor load, both of which enhance SFAF. clocking effect; subsonic compressor; wake pressure transport; local acceleration region; unsteady design +
Footnote †: journal: Applied  
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This research was funded by National Science and Technology Major Project, China (J2019-II-0005-0025). Not applicable. All the data produced in this study are contained in the manuscript text. The authors declare no conflict of interest. +++  
* [PERSON] et al. (2002) [PERSON]; [PERSON]; [PERSON]; [PERSON] Clocking Effects in a 1.5 Stage Axial Turbine--Steady and Unsteady Experimental Investigations Supported by Numerical Simulations. _J. Turbomach._**2002**, _124_, 52-60. [CrossRef]
* [PERSON] et al. (2003) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Experimental Investigation of Airfoil Wake Clocking Impacts on Aerodynamic Performance in a Two Stage Turbine Test Rig. In Proceedings of the Volume 6: Turbo Expo 2003, Parts A and B; ASMEDC: Atlanta, GA, USA, 2003; pp. 351-358. * [PERSON] (2015) [PERSON]; [PERSON] Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions. _J. Propuls. Power_**2015**, _31_, 519-526. [CrossRef]
* [PERSON] (2013) [PERSON]; [PERSON] Vane Clocking Effects on Stall Margin in a Multistage Compressor. _J. Propuls. Power_**2013**, _29_, 891-898. [CrossRef]
* [PERSON] (2010) [PERSON]; [PERSON]; [PERSON] An Experimental Study of Vane Clocking Effects on Embedded Compressor Stage Performance. _J. Turbomach._**2010**, _132_, 011018. [CrossRef]
* [PERSON] (2008) [PERSON]; [PERSON]; [PERSON] An Investigation of the Flow Physics of Vane Clocking Using Unsteady Flow Measurements. In Proceedings of the Volume 6: Turbomachinery, Parts A, B, and C; ASMEDC: Berlin, Germany, 2008; pp. 2003-2014. * [PERSON] (2018) [PERSON]; [PERSON] A Comprehensive Investigation of Blade Row Interaction Effects on Stator Loss Utilizing Vane Clocking. _J. Turbomach._**2018**, _140_, 071004. [CrossRef]
* [PERSON] et al. (2011) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] An Experimental Investigation of Stator Clocking Effects in a Two-Stage Low-Speed Axial Compressor. In _Proceedings of the Volume 7: Turbomachinery, Parts A, B, and C_; ASMEDC: Vancouver, BC, Canada, 2011; pp. 1563-1574. * [PERSON] et al. (2012) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON] The Potential of Rotor and Stator Clocking in a 2.5-Stage Low-Speed Axial Compressor. In _Proceedings of the Volume 8: Turbomachinery, Parts A, B, and C_; American Society of Mechanical Engineers: Copenhagen, Denmark, 2012; pp. 2453-2466. * [PERSON] et al. (1998) [PERSON]; [PERSON]; [PERSON] Physics of Airfoil Clocking in a High-Speed Axial Compressor.