噴流風口性能研究

A Study on the Performance of a Jet Outlet Diffuser

鄭明順(Robert Cheng)

指導教授 ： 胡石政

國立臺北科技大學/機電學院/冷凍與低溫科技研究所/碩士(2008年)

https://doi.org/10.6841/NTUT.2008.00363

摘要

空調及通風系統之主要功能為提供並維持建築物內空氣品質，人員舒適或提供設備運轉、產品生產保存之必要溫濕度條件，為達成上述目的而影響空調系統最重要的首推室內之空氣分佈，即送風口之種類及其噴射流性能為影響空氣運動之重要因素。
空調系統使用之出風口有許多種類並有不同之特性，出風口製造廠均會提供完整的性能資料，例如射程、擴散半徑等，但若使用於特殊之場所或為配合工程設計而訂作之出風口則無法獲得完整之性能資料，此時可以以幾種方法獲得: (1) 參考文獻或技術資料，以文獻之公式來推算相關數據(2) 以全尺寸於實驗室或合適之場所實際量測。(3)以CFD模擬。
本研究中以全尺寸於選定之場所量測中心線風速，以超音波3D風速計量測並記錄噴射流路徑之X、Y、Z軸風速，將收集之資料經整理後繪製Log-Log Plot後再求取K值。
經實際量測及分析後發現噴射流Zone2，Zone3之實測中心線風速與以文獻中的公式求得之風速差異不多，同時求得之K值亦相似，而且Zone 2， Zone 3之轉換區域不會因初始速度而改變與風口之相對位置。

關鍵字

噴流風口 ； 噴射氣流 ； 終端風速 ； 射程 ； 超音波3D風速計

並列摘要

The objectives of air distribution system for HVAC are to create the proper air quality and thermal comfort in the occupied zone or to maintain the required ambient condition for equipments and products storage. The ability of a system to meet minimum comfort level is determined by the air distribution within a space, which is depended on the type of supply outlets or air jets performances.
A number of air diffusers have been made with well documented data offered by the manufactures. In practice, it is not available to have the air jet dynamics for unique building outlets or special designed. There’re several ways to find the air jet dynamics: (1)Estimated from the equations published in the handbook or thesis. (2) Full-scale model experimented in the laboratory. (3)Computational fluid dynamics (CFD).
This study try to setup the full-scale model and experimented in a acceptable room, the centerline velocities of air jet were measured and recorded, then analyzing throw and distances are plotted on a non-dimension log-log plots and fine the K values for Zone 2 and Zone 3.
The results were found few of difference between the centerline velocity estimated form the equations and experiment measured, even the K value between the estimated and the experimented have the similar values. This study also show the location of transition zone will not changed by the different jet outlet discharge velocity.

並列關鍵字

Jet Outlet ； Air jet ； Terminal Velocity ； Throw ； 3D anemometer

參考文獻

[1] Etheridge, D and Sandberg, M (1996) “Building ventilation: theory and measurement”. John Wiley &Sons

[3] ASHRAE Handbook 2005 – Fundamentals, Chapter 33 “Space Air Diffusion”

[8] Baturin, V.V. “Fundamentals of industrial ventilation, 3rd ed”. 1972, Translated by O.M. Blunn. Pergamon Press, New York.

[24] S.C. Hu, “Airflow characteristics in the outlet region of a vortex room air diffuser”, 2003, Building and Environment 38 (2003) 553-561

[2] Mundt, E. (1996) “The performance of displacement ventilation systems experimental and theoretical studies”. Bulletin no 38. Dept. of Building Services Engineering, Royal Institute of Technology.