what is the impact of counter-rotating the rotor

Influence of Torque Ratio on Counter Rotating Open Rotor

·In this paper a methodology for complex counter rotating open rotor installations is set up to compute an actual test rig geometry using high performance computing capabilities of ONERA

Velocity interference in the rear rotor of a counter rotating

·A counter rotating wind turbine having two rotors rotating in opposite directions on the same axis is proposed to improve the aerodynamic performance of a wind turbine

A shock loss reduction method for the low pressure rotor of

·This paper proposes the circulation redistribution for the low pressure LP rotor of a highly loaded vaneless counter rotating turbine VCRT to reduce the LP shock losses The method is to decrease the mid span circulation and increase the tip circulation at the exit of the LP rotor with unchanged high pressure HP and LP power output The LP Blade to Blade flow

SL Helicopter Flying Handbook/Aerodynamics Shergood

·The counter clockwise rotating main rotor induces a torque trying to turn the helicopter to the right The tail rotor pushes air through it to the left thus creating a thrust to the right Since this thrust is away from the center of gravity this causes a counter clockwise torque balancing against the torque from the main rotor and a

Combination resonance and primary resonance

·Vibration response of the dual rotor system under synchronous impact Consider the dual rotor inter shaft bearing system with a defect in the inner race whose HP and LP rotors rotate in the same

Study of Rotor Blades Vibration Behavior of Counter Rotating

·Three test campaigns were carried out at CIAM C 3A test facility Turaevo Russia with the aim of investigating aerodynamic and acoustic performances of three counter rotating fan models under the European VITAL project [1 3] The second fan configuration CRTF2a [2] differs from the reference fan configuration CRTF1 by thickened blades profiling

Progress in open rotor propulsors The FAA/GE/NASA open rotor

·Wojno and Janardan Comparison of NASA 9 × 15 Low Speed Wind Tunnel Counter Rotating Open Rotor Data with GE Anechoic Facility Historic Data for Baseline F31A31 Blade Design AIAA 2013 2204 19th AIAA/CEAS Aeroacoustics Conference Berlin Germany May Scholar

Performance of a Mach Scale Coaxial Counter Rotating Rotor

·A Mach scale rotor system m in diameter was built and hover tested in three configurations two bladed single rotor four bladed single rotor and two bladed coaxial counter rotating rotor

Aerodynamic and Aeroacoustic Analysis of Counter Rotating

·The HMB3 solver has been validated for a range of rotor flow cases [47][48][49] Furthermore the authors have previously shown the ability of the HMB3 solver in predicting open rotor flows [8 50

A shock loss reduction method for the low pressure rotor of

·This paper proposes the circulation redistribution for the low pressure LP rotor of a highly loaded vaneless counter rotating turbine VCRT to reduce the LP shock losses The method is to

Insights into the nonlinear behaviors of dual rotor systems

·For example Wang et al [26] found that the frequency components of a nonlinear dual rotor system under co rotation and counter rotation conditions are different Prabith et al [24] found that the counter rotation rotor system enters the quasi periodic regime more quickly than the co rotation case when rub impact occurs

Comparative Study of a Conventional Coaxial Counter Rotating…

·Their descent speed is higher In addition from the comparison of Fig 2b and Fig 2c it follows that the upper rotor blade tip vortices of counter rotating coaxial rotor have a more complex nonlinear shape than in co rotating configuration This indicates a more complex structure of the induced velocity field of counter rotating coaxial rotor

The effect of rotational direction on the wake of

Counter rotating turbine is an axial turbine with nozzle followed by a rotor and another rotor that rotates in the opposite direction of the first one Absence of the second guide vane makes it more beneficial Present work involves computationally studying the performance and flow pattern of CRT with different stagger angles ranging from 8 to 13° in case of rotor 2 Equivalent mass flow

Comparative Study of a Conventional Coaxial Counter

·the comparison of Fig 2b and Fig 2c it follows that the upper rotor blade tip vortices of counter rotating coaxial rotor have a more complex nonlinear shape than in co rotating configuration This indicates a more complex structure of the induced velocity field of counter rotating coaxial rotor wake Figure 3 shows the airflow line patterns

Velocity interference in the rear rotor of a counter

·Velocity interference in the rear rotor of a counter rotating wind turbine Seungmin Leea 1 Eunkuk Sona 2 Soogab Leea b aDepartment of Mechanical and Aerospace Engineering Seoul National University South Korea b Institute of Advanced Aerospace Technology Seoul National University South Korea article info Article history Received 6

The complex unsteady flow exploration of a contra rotating rotor

·The complex unsteady flow exploration of a contra rotating rotor under inlet distortion K Zhang These stall characteristics of counter rotating boost stages are markedly different from the single stall patterns of traditional compressor rotor stator structures highlighting the complexity of the flow field in counter rotating stages

Counter Rotating Open Rotor CROR flow physics and simulation

·More recently Vion et al [26] performed experimental and numerical investigations of a Counter Rotating Open Rotor CROR configuration The second way of Srinivasan and McCroskey twist

PDF Effect of Rotor Spacing and Duct Diffusion Angle on

·The numerical model to predict the aerodynamic performance of the counter rotating ducted fan is developed by adopting the frozen rotor approach for steady state incompressible flow conditions

Dynamic characteristics of co rotating/counter rotating dual rotor

·The counter rotating dual rotor system in aeroengines can reduce the influence of rotors gyroscopic moments on aircrafts cut down the torque of cases and improve the flexibility of airplanes

The stability analysis of a two spool rotor system undergoing rub impact

·The parameters such as rotor stator contact stiffness coefficient of friction and clearance are varied for understanding their effects on the system response and stability Moreover the analysis is performed for two modes of rotor operations namely co rotation and counter rotation and determines their impacts on rotor stator rubbing

This document is a summary of Rotating Machinery

4 ·However if the rotating part is long in relative to its diameter and the unbalanced portion are at opposite ends or in different planes The balancing must be done so as to counter act the centrifugal force of these heavy parts when they are rotating rapidly This process is known as a running balance or dynamic balancing

Investigation on tip clearance control for the high pressure rotor

·In order to develop a tip clearance control system for an uncooled vaneless counter rotating turbine tip clearance variation of its high pressure rotor blade at off design conditions is analyzed

Progress in open rotor propulsors The FAA/GE/NASA open rotor

·Wojno and Janardan Comparison of NASA 9 × 15 Low Speed Wind Tunnel Counter Rotating Open Rotor Data with GE Anechoic Facility Historic Data for Baseline F31A31 Blade Design AIAA 2013 2204 19th AIAA/CEAS Aeroacoustics Conference Berlin Germany May Scholar

The effect of rotational direction on the wake of

Counter rotating turbine is an axial turbine with nozzle followed by a rotor and another rotor that rotates in the opposite direction of the first one Absence of the second guide vane makes it more beneficial Present work involves computationally studying the performance and flow pattern of CRT with different stagger angles ranging from 8 to 13° in case of rotor 2 Equivalent mass flow