Investigation of pressure drop in flexible ventilation ducts under different compression ratios and bending angles
- PDF / 1,827,863 Bytes
- 11 Pages / 612 x 808 pts Page_size
- 40 Downloads / 202 Views
Investigation of pressure drop in flexible ventilation ducts under different compression ratios and bending angles
1. Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin, N.T. 999077, Hong Kong, China 2. Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, 999077, Hong Kong, China 3. Environmental Control Systems, Boeing Commercial Airplanes, Everett, WA 98203, USA 4. Boeing Research & Technology, Beijing 100027, China 5. Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
Abstract
Keywords
Due to the large degree of freedom in terms of design and installation, flexible ventilation ducts
ventilation,
are commonly used in ventilation systems. However, excessive use of flexible ducts may lead to greater pressure drop and higher energy consumption. This study conducted experimental
pressure loss,
measurements to characterize the pressure drop in flexible ventilation ducts with different compression ratios and bending angles. This investigation first measured the pressure drop in
fan energy,
straight flexible ducts with four compression ratios under various airflow rates. The calculated friction factor for the straight flexible ducts was negatively associated with the compression ratio. Next, the pressure drops in single-bend flexible ducts with various bending angles from 30° to 150° were measured under various airflow rates. The calculated loss coefficient of the bend increased with the bending angle for single-bend flexible ducts. Finally, the influence of the intermediate duct length on the pressure drop across two bends was experimentally investigated. When the length of the intermediate duct was greater than eight times the inner diameter, the pressure drop across a double-bend flexible duct could be calculated from the friction factors and loss coefficients with a relative error less than 1%. The data obtained in this study can be used to
Research Article
Ho Kam Dai1, Wenjie Huang1, Liye Fu2, Chao-Hsin Lin3, Daniel Wei4, Zhongzhe Dong4, Ruoyu You2, Chun Chen1,5 ()
flex duct, friction factor, loss coefficient
Article History Received: 17 June 2020 Revised: 20 September 2020 Accepted: 30 September 2020 © Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
calculate the total pressure loss in flexible ventilation ducting systems in buildings.
1
Introduction
E-mail: [email protected]
Indoor/Outdoor Airflow and Air Quality
Flexible ducts are alternatives to regular rigid ducts for heating, ventilation, and air-conditioning (HVAC) systems in buildings or transportation vehicles. For example, in buildings, the space for running the ducts from the trunk to the branch outlets in the HVAC systems can be very limited due to the wiring or piping already installed. In commercial airplanes, the space for the ventilation ducting system is also very limited and complex in geometry due to the compact aircraft design. Under such circumstances, fle
Data Loading...
