深海原位激光多普勒测速系统

Deep-sea in-situ laser Doppler velocity measurement system

研发了一套适合深海原位测量的4000 m级激光多普勒热液流速测量样机,该系统采用一体化整体集成式设计,系统由光源模块、光学模块和多普勒信号处理模块三部分组成,封装于L 500 mm×F 205 mm的耐压舱中形成一体化光学测量探头.提出了强本振型双光束激光多普勒测速光路,原理样机在实验室对模拟速度进行测量,测量范围0.01—10 m/s,流速测量分辨率为0.001 m/s,实验结果初步证明激光多普勒测速系统的可行性.之后系统在青岛深海基地进行了耐压试验,系统在40 MPa高压下,获取信号正常.在中国水利水电科学研究院进行了速度对比测量,在0.01—0.2 m/s的低速段,与声学多普勒流速仪进行对比,最大测量相对误差为–9.43%.在0.8—9.6 m/s的高速段,与喷咀标准流速系统进行对比,最大相对测量误差为–1.65%.样机系统在海南陵水进行了浅海试验,测试了样机系统随吊车下放到50 m水深的下降速度和在水深2 m处随船的拖拽速度,试验证明,样机系统在浅海环境中工作正常,获取速度信号正常.

A set of 4000-meter laser Doppler hydrothermal velocity measurement prototype suitable for deep sea insitu measurement is developed in this work.In the system,an integrated design is adopted.The system is composed of a light source module,an optical module,and a Doppler signal processing module.The system is encapsulated in a pressure chamber with L500 mm×F205 mm to form an integrated optical measuring probe.An optical path of two-beam laser Doppler velocity measurement with strong local oscillator is proposed.The prototype is used to measure the simulated velocity in the laboratory.The measurement range is 0.01–10 m/s,and the flow velocity measurement resolution is 0.001 m/s.The experimental results preliminarily prove the feasibility of the laser Doppler velocity measurement system.After that,a withstanding voltage test on the system is conducted at the Qingdao Deep Sea Base,and the system obtains a normal signal under a high pressure of 40 MPa.A speed comparison measurement is carried out at the China Institute of Water Resources and Hydropower Research.In a low speed range from 0.01 m/s to 0.2 m/s,comparing with the acoustic Doppler velocity meter,the maximum measurement relative error is–9.43%.In a high speed range from 0.8 m/s to 9.6 m/s,comparing with the nozzle standard flow rate system,the maximum relative measurement error is–1.65%.The prototype system is tested in a shallow sea in Lingshui,Hainan.The sinking speed of the prototype system that sinks together with a crane down to a water depth of 50 m,and the towing speed of the system together with the ship at a depth of 2 m are tested.The test proves that the prototype system works normally in a shallow sea environment.