An Integrated Numerical and Experimental Analysis for Enhancing the Performance of the Hidden Ceiling Fan
| Autor: | Ming-yuan Hsieh, 謝明原 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 The hidden ceiling fan is installed itself deeply behind the ceiling floor to save the room space, eliminate the suppression sense and the possible insecurity. Because the majority part of hidden ceiling fan is embedded in the ceiling floor, the enclosing case is constructed to contain the axial-flow fan in the constrained space. Thus, the hidden ceiling fan is different from conventional ceiling fan that usually without an enclosing housing. To meet with the demand for a high-quality living circumstance, the development of a high-performance fan becomes an essential task and the topic of this research. Here, a hidden ceiling fan equipped with the 14-inch axial-flow impeller is selected from the market for a comprehensive investigation, which is integrated with flow visualization, performance evaluation, calculated efficiency, torque estimation, and acoustic analysis with the aids of numerical simulation and experimental measurement. Firstly, serious inhale-return phenomenon and blockage effect are numerical and experimentally identified in analyzing this commercial product. Also, a great agreement on the fan performances attained from CFD calculation and measurement is found to verify the reliability of this integrated effort. The approach for performance enhancement is composed of the redesigns on the axial-flow rotor and the housing. In the beginning, an optimal procedure is applied to construct the multi-airfoil impeller which is formed by several NACA four-digital airfoils. Several critical parameters are adjusted to obtain the high airflow rate from this axial-flow rotor. Next this rotor is installed in the original housing to check its aerodynamic performance numerically. Moreover, careful flow visualization and step-by-step modification are incorporated to eliminate the inhale-return phenomenon and other undesired flow pattern associated with the ceiling fan. After these modifications, a CNC-fabricated prototype including new housing and axial-flow rotor are prepared for experimental verification its aerodynamic and acoustic characteristics in AMCA test chamber and semi-anechoic room, respectively. Consequently, the results from experiment and simulation have the same trend and an acceptable deviation. Also, the test outcomes indicate that the maximum static pressure and airflow rate of the optimized axial-flow fan are increased by 33.7% and 55.48%, respectively. Moreover, the airflow rate of prototype has significantly improved by 64.57% after combining the new designs of rotor and housing. In conclusion, the accomplishment of this work not only attains a substantial improvement on the hidden ceiling fan, but also establishes a systematic and comprehensive design procedure for fan engineers. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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