國立虎尾科技大學 |

Development of advanced blade pitching kinematics for cycloturbines and cyclorotors.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Development of advanced blade pitching kinematics for cycloturbines and cyclorotors./
Author:	Adams, Zachary Howard.
Description:	1 online resource (276 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 78-03(E), Section: B.
Contained By:	Dissertation Abstracts International78-03B(E).
Subject:	Aerospace engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9781369246001

Development of advanced blade pitching kinematics for cycloturbines and cyclorotors.
Adams, Zachary Howard.

Development of advanced blade pitching kinematics for cycloturbines and cyclorotors. - 1 online resource (276 pages)

Source: Dissertation Abstracts International, Volume: 78-03(E), Section: B.

Thesis (Ph.D.)

Includes bibliographical references

Cycloturbines and cyclorotors are established concepts for extracting freesteam fluid energy and producing thrust which promise to exceed the performance of traditional horizontal axis turbines and rotors while maintaining unique operational advantages. However, their potential is not yet realized in widespread applications. A central barrier to their proliferation is the lack of fundamental understanding of the aerodynamic interaction between the turbine and the freestream flow. In particular, blade pitch must be precisely actuated throughout the revolution to achieve the proper blade angle of attack and maximize performance. So far, there is no adequate method for determining or implementing the optimal blade pitching kinematics for cyclorotors or cycloturbines. This dissertation bridges the pitching deficiency by introducing a novel low order model to predict improved pitch kinematics, experimentally demonstrating improved performance, and evaluating flow physics with a high order Navier-Stokes computational code.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369246001Subjects--Topical Terms:

686400
Aerospace engineering.
Index Terms--Genre/Form:

554714
Electronic books.

Development of advanced blade pitching kinematics for cycloturbines and cyclorotors.
LDR:06483ntm a2200433Ki 4500 001 909520
005 20180426100013.5
006 m o u
007 cr mn||||a|a||
008 190606s2016 xx obm 000 0 eng d
020 $a 9781369246001
035 $a (MiAaPQ)AAI10170548
035 $a (MiAaPQ)purdue:20163
035 $a AAI10170548
040 $a MiAaPQ $b eng $c MiAaPQ
099 $a TUL $f hyy $c available through World Wide Web
100 1 $a Adams, Zachary Howard. $3 1180342
245 1 0 $a Development of advanced blade pitching kinematics for cycloturbines and cyclorotors.
264 0 $c 2016
300 $a 1 online resource (276 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertation Abstracts International, Volume: 78-03(E), Section: B.
500 $a Adviser: Jun Chen.
502 $a Thesis (Ph.D.) $c Purdue University $d 2016.
504 $a Includes bibliographical references
520 $a Cycloturbines and cyclorotors are established concepts for extracting freesteam fluid energy and producing thrust which promise to exceed the performance of traditional horizontal axis turbines and rotors while maintaining unique operational advantages. However, their potential is not yet realized in widespread applications. A central barrier to their proliferation is the lack of fundamental understanding of the aerodynamic interaction between the turbine and the freestream flow. In particular, blade pitch must be precisely actuated throughout the revolution to achieve the proper blade angle of attack and maximize performance. So far, there is no adequate method for determining or implementing the optimal blade pitching kinematics for cyclorotors or cycloturbines. This dissertation bridges the pitching deficiency by introducing a novel low order model to predict improved pitch kinematics, experimentally demonstrating improved performance, and evaluating flow physics with a high order Navier-Stokes computational code.
520 $a The foundation for developing advanced blade pitch motions is a low order model named Fluxline Theory. Fluid calculations are performed in a coordinate system fixed to streamlines whose spatial locations are not pre-described in order to capture the flow expansion/contraction and bending through the turbine. A transformation then determines the spatial location of streamlines through the rotor disk and finally blade element method integrations determine the power and forces produced. Validation against three sets of extant cycloturbine experimental data demonstrates improvement over other existing streamtube models.
520 $a Fluxline Theory was extended by removing dependence on a blade element model to better understand how turbine-fluid interaction impacts thrust and power production. This pure momentum variation establishes a cycloturbine performance limit similar to the Betz Limit for horizontal axis wind turbines, as well as the fluid deceleration required to achieve optimum performance. A novel inverse method was developed implementing a new semi-empirical curvilinear flow blade aerodynamic coefficient model to predict optimum cycloturbine blade pitch waveforms from the ideal fluid deceleration.
520 $a These improved blade pitch waveforms were evaluated on a 1.37m diameter by 1.37m span cycloturbine to definitively characterize their improvement over existing blade pitch motions and demonstrate the practicality of a variable blade pitch system. The Fluxline Optimal pitching kinematics outperformed sinusoidal and fixed pitching kinematics. The turbine achieved a mean gross aerodynamic power coefficient of 0.44 (95\% confidence interval: [0.388,0.490]) and 0.52 (95\% confidence interval: [0.426,0.614]) at tip speed ratios (TSRs) of 1.5 and 2.25 respectively which exceeds all other low TSR vertical axis wind turbines. Two-dimensional incompressible Reynolds-averaged Navier-Stokes computational fluid dynamic simulations were used to characterize higher order effects of the blade interaction with the fluid. These simulations suggest Fluxline Optimal pitch kinematics achieve high power coefficients by evenly extracting energy from the flow without blade stall or detached turbine wakes.
520 $a Fluxline Theory was adapted to inform the design of high efficiency cyclorotors by incorporating the concept of rotor angle of attack as well as a power and drag loss model for blade support structure. A blade element version of this theory predicts rotor performance. For hovering, a simplified variation of the theory instructs that cyclorotors will achieve the greatest power loading at low disk loadings with high solidity blades pitched to maximum lift coefficient. Increasing lift coefficients in the upstream portion of the rotor disproportionately increases performance compared to magnifying lift in the downstream portion. This suggests airfoil sections that counter curvilinear flow effects could improve hovering efficiency. Additionally, the simplified hovering theory explains the cyclorotor side force which was observed experimentally, but never adequately explained. In contrast, a separate simplified version of the theory for high speed forward flight points to better rotor performance with a low solidity, high disk loading rotor operated at high advance ratios. High rotor aspect ratios will improve performance in both hover and forward flight.
520 $a A new mechanical blade pitch mechanism was designed to actuate the high efficiency blade pitch motions predicted by Fluxline Theory for both cyclorotors and cycloturbines. The mechanism optimizes blade pitch at all operating conditions via different cross sections of a three dimensionally contoured cam. Varying the position of the cam accounts for changing wind direction and velocity on a cycloturbine, or for pilot-controlled thrust vectoring, forward speed, and aircraft angle of attack as a cyclorotor. A simplified variation of the mechanism, which implemented fully aerodynamically-shrouded blade pitch links, performed flawlessly on the cycloturbine experiment.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Aerospace engineering. $3 686400
650 4 $a Mechanical engineering. $3 557493
650 4 $a Energy. $3 784773
650 4 $a Alternative Energy. $3 845381
655 7 $a Electronic books. $2 local $3 554714
690 $a 0538
690 $a 0548
690 $a 0791
690 $a 0363
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Purdue University. $b Mechanical Engineering. $3 845672
773 0 $t Dissertation Abstracts International $g 78-03B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10170548 $z click for full text (PQDT)