Leakage Monitor And Passive Location Of Coal Fired Boiler

Tube leakage accident is difficult to avoid completely, because of mal-condition in the power plant boiler. Leakage monitored timely and located accurately can make the power plant run with safety and economy. It can be effective by the technology that monitor the leakage and find the position accrately with the advantage of non-contact and passive measurement. However, the technology existed can not be used in the tube arrays such as horizontal flue and tail flue, and it also can not be used under the condition of multi-source leakage. So the technology existed is still unable to apply to the boiler.On the base of basic control equation, DDES is used in the numerical simulation of high unexpanded jet flow to obtain the unsteady flow field. The FW-H surface integral method is used to calculate the supersonic jet noise, and then analysis the noise of different conditions and aperture by sound pressure level spectrum. Directionality feature of the noise has been studied by Mohring acoustic analogy. The recognition accuracy is improved according to classify the boiler by area. Theoretical basis is provide by the simulation research for monitoring the leakage of different sections, and it has a guiding significance.Sound propagation characteristic is analysed in the horizontal flue and tail flue. PWM is used for theoretical calculation. Acoustic wave band structure is studied systematically by numerical simulation in the convection superheater, reheater and economizer with non-uniform temperature field. It is obteined that sound wave transmission characteristic is simulated in the condition of different arrays and arrangement of tube. Tube array test bench with non-uniform temperature field is designed to verify the feasibility of simulation.Several signal processing methods used for boiler tube leakage are compared, and FastEEMD method is used to analysis the signal of hair crack, and the spectrum difference of IMF is used as criteria. Negative TDOA measurement is proposed to solve the circumstance of sound source far away from base sensor. Combined with sound progagation characteristic in the furnace, TDOA measurement is studied by using FastEEMD method. Applicalbe frequence band is chosen by experiment in the boiler, the feasibility of the method is verified. Adaptive TDOA method based on z coefficient is proposed to measure the TDOA of tube array by selecting the corresponding frequency band. Large tube array test bench is designed to verify the method of TDOA measurement feasibility, and the location experiment is also designed by using the test bench.Multiple TDOA and blind source separation technology are studied for the problem of multi-source leakage in boiler. Triple-array maximum heterogeneous density cluster algorithm is proposed to solve the problem based on multiple TDOA technology, and test bench is designed to prove that it is practicable. The sparse of leakage signal and nonlinear characteristic of real hybrid signal is pointed out that blind source speration technology is still in the stage of simulation, and the simulation results coincide with experimental results on the international. Power plant boiler tube leakage monitor and location system is developed. The signal of hair crack module, partition period of location module and multi-source location module are integration to the system.