按API661设计时,空冷器迎面风速的选择

When designers work on an air-cooled heat exchanger thermal design, they commonly select face velocity in the design as a convenient means of specifying the airside flow rate.

Face velocity is defined as the average air velocity at the inlet face of the bundle. Typically, face velocity is based on standard conditions [21 °C (70 °F) and 101.3 kPa (14.696 psia)], and design face velocities vary from 2 – 4 m/s. Xace calculates

Face area = Tube length × Bundle width
Face velocity = Volumetric airside flow rate / Face area

HTRI has not conducted research to determine optimal face velocities for design. To address this open issue, members of the Communication Committee – Houston, TX, USA (CC-Houston) recently completed a parametric study of factors which affect face velocity selection, including

Based on this study, CC-Houston members propose the following general recommendations:

In addition, they provide specific face velocity ranges for different numbers of tuberows, as shown in Table I.

Table I. Range and typical values of face velocity
No. of tuberows Face velocity, m/s Typical design value, m/s
3 2.9 – 4.5 3.7
4 2.6 – 4.0 3.3
5 2.5 – 3.8 3.2
6 2.3 – 3.5 2.9
7 2.1 – 3.3 2.7
8 2.0 – 3.1 2.6
10 1.9 – 2.8 2.3
12 1.7 – 2.6 2.2

 

CC-Houston attached the complete review report of Recommending Face Velocity Ranges to the May 23, 2012, meeting minutes.

Note: The proposed face velocities in Table I are a good starting point for designers. The “best” face velocity really depends upon the specifications and constraints of each application, as outlined in CC-Houston’s report.

 

Author: admin on 2015年5月28日
Category: 文献纪要, 热工计算, 空冷器
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