PIPE-FLO Professional calculates the balanced flow rates and pressures in fluid piping systems, showing how the entire piping system operates. Using the calculated results, you can see the flow rate in each pipeline, the pressure at each pipeline junction, along with details on the operation of pumps, control valves, and components. This section describes the calculation methodology used by the PIPE-FLO Professional program. Unless stated otherwise the same calculation method is employed by PIPE-FLO Lite.

Pipeline Pressure Drop Calculations

PIPE-FLO Professional performs all head loss calculations using the Darcy-Weisbach formula; it uses the Colebrook equation to calculate the friction factor in the pipeline. This method provides accurate results for non-compressible fluids, including most process fluids. The Darcy-Weisbach method also provides satisfactory results for compressible fluids when the pressure drops in a pipeline are less than 40% of the inlet pressures.

Engineering Data Tables

PIPE-FLO Professional locates pipeline, fluid, and valve & fitting properties in engineering data tables. The customer can customize the content of the engineering data tables using the supplied Table Manager program. Using the program, you can create your own tables, modify existing data tables, or install manufacturers' tables.

PIPE-FLO Professional calculates the physical property data for fluids using the DIPPER, and Yaws methods, or a polynomial function. The user chooses a fluid from the list of installed tables and enters a temperature and pressure. The program determines the state of the fluid (liquid or vapor) along with the density, viscosity, and vapor pressure for liquids, and the density, viscosity, and specific heat ratio for vapors.

The program comes with a variety of pipe material tables that contain the pipe roughness, the available schedules or wall thickness and the available pipe diameters.

The standard valve and fitting table shipped with PIPE-FLO Professional contains the entire valve and fitting types found in the Crane Technical Paper 410. Custom valve and fitting tables can be created for various materials and pipe specifications.

Network Analysis Method

PIPE-FLO Professional calculates the balanced flow rates and pressures in a piping system using the simultaneous path adjustment method developed by Dr. Wood of the University of Kentucky. This method uses the Hardy Cross method and once the program is near a solution it then switches to the linear method to complete the calculation.

The program automatically sets up the equations for the network calculations by tracing the system loops and developing the flow and pressure drop equations needed for the network calculations.

Pump Selection & Evaluation

PIPE-FLO Professional uses the method outlined in the Hydraulic Institute Standards for Centrifugal, Rotary & Reciprocating Pumps when performing pump calculations. Various manufacturers supply Electronic Pump Catalogs to provide the information needed for pump selection and evaluation. A list of the supporting manufacturers can be found at (http://www.eng-software.com/pml/). Pumps can also be modeled by manually entering the pump performance data supplied on a typical pump curve.

Control Valve Selection & Evaluation

Control valve sizing is performed using the method outlined in the Instrument Society of America Standard ISA S75.01 Flow Equations for Sizing Control Valves. Electronic Control Valve Catalogs provide the information needed for control valve selection and evaluation. Control valves can be manually entered in the piping system model, allowing any manufacturer's valves to be modeled.

Flow Meter Sizing

Flow meter and balance orifice sizing is performed using the method outlined in the American Society of Mechanical Engineers Standard ASME MFC-3M Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and Venturi.

Detailed Program Methodology

A detailed method of solution is available at the following links:

Control Valve Library Manual