- 學位論文
週期性擺動送風葉片對具有單一進口與出口正方形容器內之暫態流場與熱傳形成週期性狀態的影響
Transient Flow and Heat Transfer Leading to Periodic State in a Square Cavity with Single Inlet and Outlet Ports Due to an Oscillating Air-Supply Guide Vane
摘要
早期的空調僅著重於對室內溫度的控制，所以只要能達到溫度需求即可，但由於全球健康意識抬頭，空氣品質對人體健康的影響廣泛受到重視，要確保空間內空氣的溫度及流動性維持在可接受的情況，便成了研究室內空調重要的一環。目前國內外的研究大多局限於噴流對室內空間穩態流場之影響，對動態流場的分析極少。為了深入瞭解週期性擺動之送風葉片對空間內流場的分佈，本研究利用計算流體力學軟體FLUENT，針對一具有單一進口與出口之正方形容器進行暫態氣流模擬分析，並研究週期性擺動之送風葉片的頻率與振幅對於室內空間氣流分佈以及壓損與熱傳性能的影響。結果顯示，瞬時壓損與紐賽數成週期性變化。在固定頻率的情況下，隨著振幅越大，瞬時室內壓損也隨之越大，而空間內瞬時紐賽數也越大；在固定振幅的情況下，頻率的改變對壓損的影響甚小，當頻率越大時，則空間內瞬時紐賽數變差。
並列摘要
In earlier years, air-conditioning only focused on the control of indoor temperature for meeting the temperature requirement. Due to the urgent demand of health concern, people gradually know how important the indoor air quality (IAQ) is. Ensuring air temperature and flowing pattern within an acceptable level has become one of the most important research topics in the HVAC industry. In the past, most researches related to indoor airflow concentrated on the effect of air jets on the indoor air distribution at steady-state condition. However, the studies of dynamic analysis on the indoor air distribution were rare. To fully understand the impact of an oscillating air-supply guide vane on the indoor air distribution, this study employed CFD software package-FLUENT to simulate transient airflow distribution within a square cavity with single inlet and outlet. The numerical study focused on the effect of frequency and amplitude of a periodically swinging guide vane on the indoor air distribution, pressure drop, and heat transfer performance. According to the numerical results, it is known that the instantaneous pressure drop and Nusselt number displayed with cyclical changes. The instantaneous pressure drop and Nusselt number increased with the increase of amplitude as the frequency is fixed. At fixed amplitude, the pressure drop was almost independent on frequency; however, the instantaneous Nusselt number became worse as the frequency increased.