Pipe sizing of district cooling distribution network using implicit Colebrook-White equation

• Main Authors: Augusto, Gerardo L., Culaba, Alvin B., Tanhueco, Renan Ma. T.
• Format: text
• Published: Animo Repository 2016
• Subjects: Friction; Pipe, Steel; Electric power distribution; Newton-Raphson method; Mechanical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/2795
• Institution: De La Salle University

An implicit solution of Colebrook-White equation was used in calculating the friction factor for commercial steel pipes using Newton-Raphson method with Reynolds number ranging from 4.0×103 to 1.3×107. Initial value for iterative friction factor estimation was based on expanded form of Colebrook-White equation for larger values of Reynolds number with tolerance value of 1.0×10-8. Numerical results were compared with known explicit solutions and iterative procedure proposed by Lester in which, their mean difference, root-mean square deviation, mean relative error and correlation coefficient were evaluated. Correlation coefficients equal to unity and overall mean relative error of 4.821×10-8 were achieved for all fifteen (15) pipe cases with nominal diameters ranging from 100mmto 1,500mmwhen compared with iterative solution suggested by Lester. Student's t-test for paired data was also used which yielded a calculated t-value of -5.406×10-4. Combining the piping network design criteria with the logical structure of friction factor calculation determines the pipe size of distribution network and defines the boundaries of chilled-water velocities at different pressure drop limits as a function of commercial steel pipe diameter according to ANSI B36.1.