Performance Analysis And Two-level Motor’s Power Matching Research Under Variable Conditions On The Counter-Rotating Fan

The counter-rotating fan is a kind of rotating turbomachineries. It is aventilation device which is widely used in subway, colliery, railways, shippingand other fields. It has the following characteristics such as good reverseventilation performance, high efficiency, compact overall structure, flexibleapplication, etc. When the counter-rotating fan is actually running, installationangle can be adjusted based on the needs of working conditions. Then thepressure provided by the two-level motors and the two-level motors’ outputpower may appear mismatches. Therefore, the numerical simulation based on thecomputation fluid dynamics technology is an important research method which isadopted to study complex fluid flow and to forecast fan performance.Firstly, in this dissertation, the model FBDCZNo.14counter-rotating fan isused as a research object. The counter-rotating fan’s three-dimensional physicalmodel of the global flow field is built with SolidWorks software.Secondly, the theory of counter-rotating fan’s performance test is introduced,and experimental data are analyzed. At the same time, the conditions of importand export are identified. Combined with experimental data and mathematicalmodels, the numerical simulation of the counter-rotating fan is completed, andthe software of FLUENT is used in the process of numerical simulation. Bycomparing the simulation results and experimental data, this method of numericalsimulation is verified to be accurate. Respectively changing the two impellers’blade angle five times, the characteristics of pressure, efficiency and shaft powerare acquired, and the variation of performance is summarized. Changing thespeed of two motors and the tip clearance, the counter-rotating fan’s performance parameters are studied, too.Finally, when the counter-rotating fan operates in a stable condition zone,with the longer ventilation distance, air flow is significantly reduced, and twomotors’ output power is difficult to match. According to the problem, theperformance LINE (point-point) matching between the two-level counter-rotatingblades and electric machines is studied. Then, the reason that why the motor iseasy to burn out is explained, it can lay the foundation for selecting motors andcontribute to the safe operation of the counter-rotating fan.