Yuan Wenhua

Study on the Exhaust Back-pressure Threshold-value MAP for the Diesel Particulate Filter Regeneration

The back-pressure gradually rises with the increasing particulate sediment during the diesel particulate filter (DPF) working. it will be harmful to the fuel economy of diesel engine. In order to keep the good fuel economy, when the back-pressure exceeds the set threshold-value, the sediment particulate must be cleaned in DPF namely regeneration, therefore, the exhaust back-pressure threshold-value for every working condition is pivotal to the DPF regeneration time. Taking the burner-type DPF as an example, through the real-time measure data of the diesel engine rotate speed, load, corresponding fuel consumption and DPF exhaust back-pressure, with the data processing method and the diesel engine fuel consumption ratio mode based on the multiple regression theory, taking advantage of MATLAB mighty function in mathematic operation and figure disposal, the fuel consumption characteristic map of the diesel engine equipped with DPF is plotted. Further, with the above corresponding test data, the DPF regeneration MAP of exhaust back-pressure threshold-value is obtained.

Study on the Noise Prediction for the Gear Box of the Large Wind Power Yaw Reducer

In order to predict the noise of the large wind power yaw reducer, the virtual prototyping model of the large wind power yaw reducer was established based on its working conditions, and the vibration response based on the modal was solved. Noise of the reducers gear box was predicted by combining the finite element method and acoustic boundary element method, and the results show that the main peak noise frequencies are 420Hz, 590Hz and 1190Hz, the sound pressure which is relatively high is mainly distributed in the low frequency band, and the sound pressure is larger especially when the frequency is between 300Hz and 1200Hz, The corresponding sound pressure level under the noise frequencies of 420Hz, 590Hz and 1190Hz are 82.716dB, 67.333dB and 47.557dB, and the area with large noise is small in the radiation sound field, but the sound pressure is higher than 78.6dB in some area, which have a great influence on environment. The noise prediction results can provide reference and foundation for the study on noise reduction of the large wind power yaw reducer.

Engine's Working Characteristics with Blended Fuel of Biodiesel and Diesel Oil in HCCI Combustion Mode

The mechanism of homogeneous charge compression ignition (HCCI) combustion is introduced. Based on single zone model of HCCI combustion under early injection, coupled with fuel oxidation reaction dynamical model, the mathematics combustion model in cylinder is built and simulated, then the engines working characteristics combusted with the biodiesel and diesel oil is compared with the original, it shows that the calculation is matched with the trial results well. And through analyzing the HCCI combustion performance with the different mixture ratio of biodiesel and diesel oil, the two-stage heat release characteristics is appeared in the combustion, and the instantaneous cylinder pressure peak value is increased with the increasing mixture ratio.

Residual Fatigue Life Evaluation of the Engine Crank Shaft Based on the Cumulative Fatigue Damage Theory

With the cumulative fatigue damage theory, the residual fatigue life assessment model of crankshaft was built and its residual life was evaluated based on the history statistical working conditions. First, the three-dimension solid model of the crankshaft was formed by Pro/E software, and then imported into finite element analysis software ANSYS to perform dynamic response calculation under typical working conditions, the high stress area of structure, namely that of the most severe cumulative fatigue damage, was obtained. Then the stress-time history was carried out rain-flow counting by the finite element analysis, and the fatigue load spectrum was established based on history statistics record. The fatigue residual life assessment model was built with nominal stress approach and one application example was given at last.

Study on Monitoring Data Mining of Steam Turbine Based on Interactive Association Rules

Real-time monitoring data mining has been a necessary means of improving operational efficiency, economic safety and fault detection of power plant. Based on the data mining arithmetic of interactive association rules and taken full advantage of the association characteristics of real-time test-spot data during the power steam turbine run, the principle of mining quantificational association rule in parameters is put forward among the real-time monitor data of steam turbine. Through analyzing the practical run results of a certain steam turbine with the data mining method based on the interactive rule, it shows that it can supervise stream turbine run and condition monitoring, and afford model reference and decision-making supporting for the fault diagnose and condition-based maintenance.