The Performance Characteristics of The Low Head Cross Flow Turbine Using Nozzle Roof Curvature Radius Centered on Shaft Axis

Abstract

The experimental study was intended to investigate the performance characteristics of three cross flow turbine models using nozzle roof curvature radius centered on shaft axis designed on the same flow rate, runner diameter and rotational speed with each model having different runner width as well as its nozzle entry arc. The nozzle and runner width were designed as the fuction of the nozzle entry arc, the shorter pair of runner-nozzle, the larger nozzle entry arc and vise versa. The nozzle entry arcs used in this experimental study were 75 o , 90 o and 120 o. In addition, the three models had equal cross sectional area of nozzle entry. The three turbine nozzles were designed to have roof curvature radius centered on shaft axis. The nozzle roof curvature were expected to be able to deliver water in better direction as well as its flow condition as the water entered the tubine runner. The experimental test rig consisted of three turbine models, pump, piping systems, magnetic flow meter, and tachometer. The Flow rates, that entered the turbine, supplied by the pump, were measured by the magnetic flow meter. The power generated on the turbine shaft was determined by measuring the torsion forces detected by using a spring balance and turbine speeds were detected by a hand held tachometer. The turbine performance characteristics were shown by the relation of efficiency versus flow rate, head, and specific speed; as well as the relation of efficiency versus velocity ratio and speed ratio. The velocity ratio was the ratio of runner pheripheral velocity to water jet velocity that entered the runner; the speed ratio was the ratio of runner speed to water jet speed entering the runner. The results of the study indicated that best efficiency points increased as the nozzle entry arc decreased or on the other hand best effisiency points decreased as the nozzle entry arc increased. The results showed that the cross flow turbine using 75 and 90 degree entry arcs indicated efficiency and power which was higher than that of turbine with 120 degree nozzle entry arc.

Consideraciones de diseño de una turbina Michell-Banki

“…Sutikno et al [55] estudiaron experimentalmente tres modelos de turbina de flujo cruzado con diferentes ángulos para el arco de entrada: 75°, 90° y 120°. La plataforma de prueba experimental consistió en los tres modelos de turbina, bomba, sistemas de tuberías, medidor de flujo magnético y tacómetro.…”

The Performance of a Cross-flow Turbine as a Function of Flowrates and Guide Vane Angles

“…Experimental research [7][8][9][10] investigated the impact of the aspect ratio of the rotor diameter and the span of the blade on a cross-flow turbine. Because of the limited interaction of the blade support, the study determined that the operational effectiveness of the turbine depends on a combination of Reynolds and Froude numbers.…”