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Research Article

Investigation of pressure drop in flexible ventilation ducts under different compression ratios and bending angles

Ho Kam Dai1, Wenjie Huang1, Liye Fu2, Chao-Hsin Lin3, Daniel Wei4, Zhongzhe Dong4, Ruoyu You2, Chun Chen1,5( )
Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin, N.T. 999077, Hong Kong, China
Department of Building Services Engineering, The Hong Kong Polytechnic University, Kowloon, 999077, Hong Kong, China
Environmental Control Systems, Boeing Commercial Airplanes, Everett, WA 98203, USA
Boeing Research & Technology, Beijing 100027, China
Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
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Abstract

Due to the large degree of freedom in terms of design and installation, flexible ventilation ducts 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 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 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 calculate the total pressure loss in flexible ventilation ducting systems in buildings.

Keywords

ventilationpressure lossflex ductfan energyfriction factorloss coefficient

References

 
Abushakra B, Walker IS, Sherman MH (2004). Compression effects on pressure loss in flexible HVAC ducts. HVAC&R Research, 10: 275-289.
Crossref Google Scholar
 
Agirman A, Cetin YE, Avci M, Aydin O (2020). Effect of air exhaust location on surgical site particle distribution in an operating room. Building Simulation, 13: 979-988.
Crossref Google Scholar
 
ASHRAE (2005). ASHRAE Handbook—Fundamentals, Table 1. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
 
ASHRAE (2017). ASHRAE Standard 120-2017: Method of testing to determine flow resistance of Hvac ducts and fittings. Atlanta: American Society of Heating, Refrigerating and Air-Conditioning Engineers.
 
Brown GO (2002). Henry Darcy and the making of a law. Water Resources Research, 38: 1-12.
Crossref Google Scholar
 
Chen H, Cai WJ, Chen C (2016a). Model-based method for testing, adjusting and balancing of HVAC duct system. Energy and Buildings, 126: 498-507.
Crossref Google Scholar
 
Chen C, Zhang X, Groll E, McKibben A, Long N, et al. (2016b). A method of assessing the energy cost saving from using an effective door closer. Energy and Buildings, 118: 329-338.
Crossref Google Scholar
 
Culp C, Cantrill D (2009). Static pressure losses in 12", 14", and 16" non-metallic flexible ducts with compression and sag. ASHRAE Transactions, 115(1): 622-628.
Google Scholar
 
Culp C (2011). HVAC flexible duct pressure loss measurements. ASHRAE Research Project RP-1333 Final Report.
 
Du X, Wei A, Fang Y, Yang Z, Wei D, et al. (2020). The effect of bend angle on pressure drop and flow behavior in a corrugated duct. Acta Mechanica, 231: 3755-3777.
Crossref Google Scholar
 
Gibbs DC, Idem S (2010). Measured and predicted pressure loss in corrugated spiral duct. ASHRAE Transactions, 116(2): 380-386.
Google Scholar
 
Griggs EI, Swim WB, Henderson GH (1987). Resistance to flow of round galvanized ducts. ASHRAE Transactions, 93(1): 3-16.
Google Scholar
 
Griggs EI, Khodabakhsh-Sharifabad F (1992). Flow characteristics in rectangular ducts. ASHRAE Transactions, 98(1): 116-127.
Google Scholar
 
Hodges RK, Kulkarni D, Idem S (2013). Pressure loss in fully stretched nonmetallic flexible duct with a bend. HVAC&R Research, 19: 87-100.
Google Scholar
 
Huebscher RG (1948). Friction equivalents for round, square and rectangular ducts. ASHVE Transactions, 54: 101-118.
Google Scholar
 
Kokayko M, Jolton J, Beggs T, Walthour TS, Dickson B (1996). Residential Ductwork and Plenum Box Bench Tests. IBACOS Burt Hill Project 95006.
 
Kulkarni D, Khaire S, Idem S (2009). Pressure loss of corrugated spiral duct. ASHRAE Transactions, 115(1): 28-34.
Google Scholar
 
Kulkarni D, Idem S (2015). Loss coefficients of bends in fully stretched nonmetallic flexible ducts. Science and Technology for the Built Environment, 21: 413-419.
Crossref Google Scholar
 
Liu W, You R, Chen C (2019). Modeling transient particle transport by fast fluid dynamics with the Markov chain method. Building Simulation, 12: 881-889.
Crossref Google Scholar
 
Mutlu M (2020). Numerical investigation of indoor air quality in a floor heated room with different air change rates. Building Simulation, 13: 1063-1075.
Crossref Google Scholar
 
Mylaram NK, Idem S (2005). Pressure loss coefficient measurements of two close-coupled HVAC elbows. HVAC&R Research, 11: 133-146.
Crossref Google Scholar
 
Nalla AN, Idem S (2012). Laboratory testing of saddletap tees to determine loss coefficients. ASHRAE Transactions, 118(1): 1131-1145.
Google Scholar
 
Ojima J (2017). Decline of the performance of a portable axial-flow fan due to the friction and duct bending loss of a connected flexible duct. Journal of Occupational Health, 59: 210-213.
Crossref Google Scholar
 
Pan Y, Lin C-H, Wei D, Chen C (2019). Experimental measurements and large eddy simulation of particle deposition distribution around a multi-slot diffuser. Building and Environment, 150: 156-163.
Crossref Google Scholar
 
Paruchuri A, Idem S (2018). Experimental comparison of pressure loss in typical flexible and sheet metal residential duct systems. ASHRAE Transactions, 124(2): 102-115.
Google Scholar
 
Salehi M, Sleiti AK, Idem S (2017). Study to identify computational fluid dynamics models for use in determining HVAC duct fitting loss coefficients. Science and Technology for the Built Environment, 23: 181-191.
Crossref Google Scholar
 
Sun Y, Ford SE, Zhang Y (2015). Laboratory testing of flat oval transitions to determine loss coefficients (RP-1606). Science and Technology for the Built Environment, 21: 386-395.
Crossref Google Scholar
 
Townsend B, Khodabakhsh-Sharifabad F, Idem S (1996). Loss coefficient measurements for flat oval elbows and transitions. ASHRAE Transactions, 102(2): 159-169.
Google Scholar
 
Weaver K, Culp C (2007). Static pressure losses in nonmetallic flexible duct (6˝, 8˝, and 10˝). ASHRAE Transactions, 113(2): 400-405.
Google Scholar
Building Simulation
Volume 14 Issue 4,
August 2021
Pages 1251-1261
DOI: 10.1007/s12273-020-0737-8
Cite this article:
Dai HK, Huang W, Fu L, et al. Investigation of pressure drop in flexible ventilation ducts under different compression ratios and bending angles. Building Simulation, 2021, 14(4): 1251-1261. https://doi.org/10.1007/s12273-020-0737-8

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Received: 17 June 2020
Accepted: 30 September 2020
Published: 12 November 2020
© Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
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