LE 2 Incompressible Flow Of Pipes II

• A series piping system may consist of two or more nodes, all in one continuous connection.
• By virtue of the principle of the conservation of mass, the mass flow rate through the entire system remains constant regardless of the diameters of the individual pipes.
• There are 3 common types of problems involving series piping systems:

  1. Type I: Unknown Driving Force
  2. Type II: Unknown Flow Rate
  3. Type III: Unknown Line Size
• Type I - This type of problem is straightforward and explicit
• Correlations for pipe losses were developed for full pipes with circular cross-sections. Fortunately, we can extend their use to partially full pipe flows and noncircular cross sections using the concept of hydraulic diameter
• the use of hydraulic diameter is an approximation that allows flow calculations to be treated as a full-flow-in-a-circular-pipe problem by using Dh in place of D
• Type II - this type of problem uses iterative method
• Reynolds number should be assumed as highly turbulent
• Type III - this type of problem uses trial and error method
• Pipe sizes are based on recommended velocities and general pressure drops
• Capacity is first set by the demands of the project. There are three classifications at which capacity is specified:

  1. Normal flow
  2. Minimum flow
  3. Rated flow
• Normal flow - the material balance flow
• Minimum flow - usually 50% of the normal flow
• Rated flow - 10% greater than the normal flow for most services; 20% greater than the normal flow if sudden change is significant.
• Pump hydraulics - Account for losses/gains in elevation, line losses, fittings and valves, and process equipment and instrumentation.