Design Of Turbine Cavitation Noise Monitoring Software

Cavitation is the process of turbine operation has emerged as an inevitable destruction of the phenomenon. It seriously affects the turbine's efficiency and longevity. And fluid dynamics has been found that all of the machinery, equipment and components, will have cavitation damage. Beyond the control of cavitation can have serious and even catastrophic consequences. In hydraulic turbine specific speed mixed flow from low-to high-speed U-flow ratio, as well as the impact of Turtine Delivery will be subject to cavitation erosion hazards. The valves in the piping system and its accessories, for the operation of flow change very often, cavitation erosion would also be affected. Visible cavitation is not to be underestimated. Turbines are based on the previous post-maintenance approach, it is clear that maintenance costs are very high. Therefore, the establishment of a real-time monitoring of turbine cavitation system is very necessary.The phenomenon of cavitation is relatively common, the impact of the project is also more prominent, and with the development of national economy, cavitation issue will be more complicated. As the micro-cavitation, instantaneous, random complex phenomenon, so far, the cavitation and cavitation theory and a lot of research results was not satisfactory, most of the theories are at the stage of conjecture or assumptions, many problems still pending further study. Turbine cavitation detection methods commonly used energy method, high-speed photography, flash frequency of observation and detection methods such as cavitation noise. Taking into account the turbine is in a sealed scroll work environment, turbine during operation, a result of blade rotation, draft tube surges, impact, mechanical wear, electromagnetic vibration and cavitation noise generated, therefore, turbine noise in the vicinity of the turbine itself will often carry the structural information and operation status information. Theoretically, the noise signal can be used entirely on the turbine running status and fault-line monitoring and forecasting, comprehensive consideration of a variety of turbine air monitoring system pros and cons of research results, taking into account the cavitation noise, which best reflects the cavitation level of the main features of the signal, decided to adopt the method for monitoring cavitation noise, the system design is based on this method.This system is developed by the use of laptop sound card comes with a set of LabVIEW-based portable turbine cavitation monitoring system, establishment of monitoring alarm systems, it is necessary to find at the scene that reflects the situation of cavitation characteristics of the signal, and analyze the characteristics of the signal with the degree of cavitation and change the law by monitoring the characteristics of the signal-to-air to reach the degree of real-time monitoring purposes. This system is a hydro-generator unit is installed on the designated location hydrophone, collecting work, accompanied by a series of turbine cavitation noise generated by its proper identification processing, real-time shows the time domain and frequency domain on the characteristics, and with the criteria established by comparison in order to facilitate a timely understanding of turbine working conditions, to determine whether cavitation. Once when the selected system parameters to achieve the criterion set, then that turbine generated cavitation, began to alarm notify the staff in order to timely modify the turbine operating parameters, timely adjustment of operating conditions, one optimize the turbine's efficiency, to minimize the losses caused by cavitation. There is also able to extend their useful life. This is the system's design.