摘要
There is an increasing interest in cross flow turbines(also known as Banki turbines) for small and low head applications because of their simple structure as well as low capital and maintenance costs.The present work aims at implementing the direct drive turbine(DDT) of cross flow type for wave power generation.A numerical wave tank was used to simulate the waves and after obtaining the desired wave properties;the augmentation channel plus the front guide nozzle and rear chamber were integrated to the numerical wave tank.The waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank inlet.The inlet which was modeled as a plate wall moved sinusoidally with the general function x = asinω t.The augmentation channel consisted of a front nozzle,rear nozzle and an internal fluid region which represented the turbine housing.The front and rear nozzles were geometrically the same.Three different front guide nozzle configurations were studied:a standard guide nozzle which was originally attached to the augmentation channel and two other front guide nozzles of different geometries.The purpose of this study is to observe how the front guide nozzle shape influences the flow downstream,mainly in the augmenta-tion channel,water power and the first stage energy conversion.The analysis was performed using a commercial CFD code ANSYS-CFX.The results of the flow in the augmentation channel for the three front guide nozzles are presented in this paper.
There is an increasing interest in cross flow turbines(also known as Banki turbines) for small and low head applications because of their simple structure as well as low capital and maintenance costs.The present work aims at implementing the direct drive turbine(DDT) of cross flow type for wave power generation.A numerical wave tank was used to simulate the waves and after obtaining the desired wave properties;the augmentation channel plus the front guide nozzle and rear chamber were integrated to the numerical wave tank.The waves in the numerical wave tank were generated by a piston type wave maker which was located at the wave tank inlet.The inlet which was modeled as a plate wall moved sinusoidally with the general function x = asinω t.The augmentation channel consisted of a front nozzle,rear nozzle and an internal fluid region which represented the turbine housing.The front and rear nozzles were geometrically the same.Three different front guide nozzle configurations were studied:a standard guide nozzle which was originally attached to the augmentation channel and two other front guide nozzles of different geometries.The purpose of this study is to observe how the front guide nozzle shape influences the flow downstream,mainly in the augmenta-tion channel,water power and the first stage energy conversion.The analysis was performed using a commercial CFD code ANSYS-CFX.The results of the flow in the augmentation channel for the three front guide nozzles are presented in this paper.
