Performance Analysis of an Undershot Cross-Flow Water Turbine with Straight Blades

This paper describes the possibility of an improvement of torque performance and hydrodynamic forces on a vertical axis type water turbine, used for marine current generating system. The water turbine analyzed here is based on a Darrieus turbine with vertical blades. We considered possibilities of controlling the angle of attack of blades in order to improve the starting performance and to reduce energy loss during the rotation of the turbine. We used blade-element/ momentum theory in order to investigate the variations appearing in torque performance when the angle of attack were controlled. We also proved the validity of our predictions of hydrodynamic forces on the blade and the turbine, made through CFD calculation, by comparing them with the results of corresponding model tests in a current channel. In the corresponding model test we investigated not only the hydrodynamic forces on the turbine with three fixed blades, but also the inline force and the cross-flow force on the rotating turbine with three blades. Regarding the cyclic pitching of turbine blades, results suggest that significant increase in average turbine torque is possible.

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Performance Analysis and Limiting Parameters of a Cross-flow Membrane-based Liquid-desiccant Air Dehumidifiers

International Journal of Refrigeration ◽

10.1016/j.ijrefrig.2021.09.010 ◽

2021 ◽

Author(s):

Behnam Ahmadi ◽

Masoud Ahmadi ◽

Kashif Nawaz ◽

Ayyoub M. Momen ◽

Sajjad Bigham

Keyword(s):

Performance Analysis ◽

Cross Flow ◽

Liquid Desiccant ◽

Limiting Parameters

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Radial Thrust of Low-Head Cross-Flow Water Turbine.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.61.3012 ◽

1995 ◽

Vol 61 (588) ◽

pp. 3012-3017

Author(s):

Takaya Kitahora ◽

Junichi Kurokawa ◽

Tomitarou Toyokura

Keyword(s):

Cross Flow ◽

Water Turbine ◽

Low Head ◽

Radial Thrust

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3D RANS Modeling of a Cross Flow Water Turbine

Advances in Hydroinformatics ◽

10.1007/978-981-4451-42-0_33 ◽

2013 ◽

pp. 405-418 ◽

Cited By ~ 1

Author(s):

Christian Pellone ◽

Thierry Maitre ◽

Ervin Amet

Keyword(s):

Cross Flow ◽

Water Turbine ◽

Rans Modeling

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Performance Analysis of Multi-Pass Cross-Flow Heat Exchangers

Volume 8B: Heat Transfer and Thermal Engineering ◽

10.1115/imece2018-87049 ◽

2018 ◽

Author(s):

Kiran Lankalapalli ◽

Ahmed ElSawy ◽

Stephen Idem

Keyword(s):

Heat Exchanger ◽

Performance Analysis ◽

Thermal Performance ◽

Heat Exchangers ◽

Cross Flow ◽

Threshold Value ◽

Finned Tube ◽

Flow Heat ◽

Rate Ratios ◽

Side Flow

A steady state sensible performance analysis of multi-pass cross-flow finned-tube heat exchangers is reported. The investigation considers various flow circuiting, such as counter cross-flow, parallel cross-flow, and cross-flow where the tube-side flow is in parallel. A previously developed matrix approach is used to evaluate the heat exchanger performance in each tube pass. The equations required to model the thermal performance of these configurations are presented, and the thermal performance is compared for each type of flow circuiting. Thereafter a parametric study on cross-flow heat exchanger performance is performed by varying physically significant parameters such as number of transfer units (NTU) and capacity rate ratios, and the graphical results for each type of flow circuiting are presented both for both two-pass and three-pass arrangements. A consistent criterion is proposed for each case, wherein increasing the NTU beyond a certain threshold value does not significantly improve heat exchanger thermal performance.

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