examples_wwang[Turbo]
- 1. Page 1 PROJECT EXAMPLES 1. Aerodynamic Performance Optimization of a Whole Centrifugal Fan (2004) <Journal of HVAC&R Research, 2005, 11(2). 263~283.> Numerical simulation of the flow field was carried out for a whole centrifugal fan to consider the interaction of three parts—inlet, impeller, and scroll. A sample fan based on the optimum design was manufactured and tested. The numerical prediction agrees well with the test data. The effects of the blade inlet angle and the gap between impeller and inlet on the fan performance are quantitatively analyzed. Particularly the energy loss in every passage, including the gap loss and the leakage flow rate in the gap, are discussed in detail in the paper. Total Pressure (Pa) Total Efficiency (%) Shaft Power (kW) Experiment 1245 85.3 4.42 CFD 1235 83.8 4.50 2. Shaft Power Matching for Contra-rotating Axial Flow Fan (2005) <Journal of HVAC&R Research, 2007, 13(1). 141~162.> The purpose of shaft power matching of contra-rotating axial flow fans (CRAFF) is to ensure the best utilization of the motors at their rated power while not to overload them at the operation. Based on velocity triangle analysis and numerical simulation results, a design guideline based on the selection of shaft power matching coefficient is proposed and validated by the test data from 6 sample fans.
- 2. Page 2 3. Blade Cutting Effects to Axial Cooling Fan (2005) <Journal of Tsinghua University (Sci & Tech), 2007, 47(2). 260~263.> Blade cutting is commonly used in fan design to maintain the required tip clearance but the effects on the fan performance are not well known. Experiments described in this paper indicate that blade cutting substantially reduces the maximum discharge and the fan efficiency. The simulated fan performance agrees well with the test data. The numerical results show that blade cutting causes the development of tip clearance vortices and blade passage blockages, which reduce the flow rate and the work done by the blade. Therefore, blade cutting causes more significant performance degradation than shroud enlarging, especially for the maximum discharge which may be reduced too much to be used in practice. 4. Aerodynamic Performance Test System Design for Fans and Blowers (2006) I have designed the above chamber type fan test system (based on ANSI/AMCA 210-99) for the Fluid Acoustics Lab of Tsinghua University in 2006, and completed the aerodynamic performance tests for several fan and blower products for leading HVAC industries.
- 3. Page 3 5. Vortex Shedding Noise of a Centrifugal Impeller (2006) < J. Acoust. Soc. Am. 119, 3412 (2006).> The main noise source in a centrifugal impeller is the fluctuating force on blade surfaces caused by the vortex shedding from blade trailing edges. A method of numerical prediction of vortex shedding noise radiated by a commercial centrifugal impeller is presented, based on a vortex flow model developed by Lee in 1993. The total SPL of the noise is predicted and the results agree with the experimental data within 3 dB near the design operation. 6. BPF Noise Prediction of a Centrifugal Fan (2007) Transient flow field in a centrifugal fan (same impeller, three volutes with different gap ratios) is numerically simulated. The wall pressure fluctuation near the volute tongue and impeller blades are obtained. Using the FWH equations, the far field sound at BPF is calculated which agree well with the test data.
- 4. Page 4 7. Numerical Prediction of Turbulent Noises for Axial Cooling Fans (2011) < Journal of HVAC&R Research, 2011, 17(5). 781~797.> A statistical model was established for predicting the broadband turbulent noise of axial flow fans. First, an integral formula was deduced based on the FWH equations for the purpose of calculating the sound power spectrum. The auto-correlation spectrum of the fluctuating pressure on the fan blades was modeled by a two-section exponential function. The characteristic aerodynamic parameters were obtained by solving the RANS equations and used to normalize the auto-correlation spectrum. Then, the unknown coefficients in the exponential function were determined by fitting the experimental noise spectra for two typical and commercially available axial flow cooling fans. Finally, under the conditions of retaining the similar aerodynamic performances of the two baseline fans, a new fan design was developed and optimized using this method, of which the overall noise level was 2 dB lower than the quieter of the two baseline fans. The predicted noise spectra for all three fans agreed very well with the experimental data. 8. Turbine Blade Test Stand Design and Performance Testing (2013) I have designed a new test stand for the 2.125” turbodrill performance measurement. It is the first measurement system on our company’s history that allow measurement of a single turbine blade stage. With this system, I successfully measured the pressure, torque, thrust and rpm of the 2.125” turbine blade. I also studied the performance drop with blade worn developed. The measurement results provided data for validating the CFD design method.
- 5. Page 5 9. Relationship between Stage Count and Stall Torque of a Turbodrill (2015) <Schlumberger J. of Modeling, Design, and Simulation, 2015, V6> The stall torque of a turbodrill is the sum of the torque of each individual turbine blade stage. From design practices, a turbodrill will always need more blade stages instead of more aggressive blade outflow angles in order to reach a higher stall torque output. However, the relationship between the tool’s stall torque and the stage count under the input power limitation has never been quantitatively studied before. In this paper, a simple theoretical model is presented to establish such a relationship. The model shows that the stall torque of a turbodrill is proportional to the square root of the stage count. Such a relationship has been further validated by CFD simulation results based on 8 different turbine blade designs with different blade diameters and outflow angles. Stator Rotor