Towing and circulating tanks tidal energy converter test results

A comparative "Round Robin" testing program has been conducted as part of the EC FP VII MaRINET program in order to evaluate the impact of different experimental facilities on the test results. The aim of the trials was to test the same model tidal turbine in four different test facilities to explore the sensitivity of the results to the choice of facility. The facilities used in the testing program include two towing tanks, at CNR-INSEAN (Rome, 220 m long) and at Strathclyde University (Glasgow, 76 m long), and two recirculating tanks at CNR-INSEAN (Rome) and at IFREMER (Boulogne sur mer). The model consists of a three-bladed horizontal axis turbine, which is D=0.7m in diameter. The rotor is connected to a motor-gearbox assembly consisting of a gearbox, a DC motor, a ballast load and a motor speed control unit, providing an active rotor speed control. The turbine blades are designed from a NACA 63-418 profile. A torque meter is placed between the rotor and the gearbox for torque measurements. The forces and moments acting on the structure are obtained by means of a six-component load cell, which measures the three force components and the three moment components and the torque by a torque sensor directly fixed between the rotor and the motor. All signals coming from the load-cell, the torque-meter and the motor are recorded synchronously at a sample frequency of 100Hz. In each tank, the turbine depth is kept constant at 1 m under the free surface. The turbine is fixed on a moving carriage in the towing tanks and on a customised mounting in the flume tanks. The flow velocity or carriage velocity is chosen and fixed for each set of tests; the turbine rotation speed is then varied to adjust the tip speed ratio. The rotational speed is measured and controlled for each measurement point, but is adjusted manually.

本对比性轮转（Round Robin）测试计划作为欧盟委员会第七框架计划（FP7）MaRINET项目的组成部分，旨在评估不同实验设施对测试结果的影响。本次试验的目标为在4座不同的测试设施中测试同一型号的潮流能涡轮机，以探究测试结果对设施选择的敏感性。本次测试计划使用的设施包括两座拖曳水池（towing tank）：分别位于罗马的CNR-INSEAN（长220米）以及格拉斯哥的斯特拉斯克莱德大学（长76米），另有两座循环水槽（recirculating tank），分别位于罗马的CNR-INSEAN与滨海布洛涅的IFREMER。本次测试的模型为三叶水平轴涡轮机，直径D=0.7米。转子与电机-齿轮箱组件相连，该组件包含齿轮箱、直流电机（DC motor）、压载负载以及电机转速控制单元，可实现主动转子转速控制。该涡轮机叶片采用NACA 63-418翼型设计。在转子与齿轮箱之间安装有扭矩仪（torque meter），用于扭矩测量。作用于该结构的力与力矩通过六分量测力传感器（six-component load cell）获取，该传感器可测量三个力分量与三个力矩分量，而扭矩则通过直接固定在转子与电机之间的扭矩传感器完成测量。来自测力传感器、扭矩仪与电机的所有信号均以100Hz的采样频率进行同步记录。在每座水池中，涡轮机的浸入深度均保持为自由液面下1米。在拖曳水池中，涡轮机固定于移动台车上；在槽式水槽（flume tank）中，则固定于定制安装架上。每组测试均预先选定并固定水流速度或台车速度，随后通过调整涡轮机转速来调节叶尖速比（tip speed ratio）。每个测量点的转速均会被测量与控制，但转速调整需手动完成。