Overview of AFT Arrow

Welcome to AFT Arrow™ - a visual platform for modeling compressible flow in pipe networks! See what's new in this version.

AFT Arrow brings increased productivity to the pipe flow engineer by combining traditional engineering hydraulic analysis with an intuitive graphical user interface. By implementing a drag-and-drop method of pipe flow modeling, AFT Arrow simplifies the pipe network modeling process.

AFT Arrow can show both input data and analysis results in visual form, allowing rapid analysis of a model's validity. Identifying poor assumptions, catching typographical or modeling errors, and rerunning models are all accelerated because of AFT Arrow's graphical environment.

Whether your pipe system model will be used to evaluate and improve an existing system or to design a new one, AFT Arrow increases your productivity in the modeling process.

What Can AFT Arrow Do?

AFT Arrow can be used to model a wide variety of compressible flow systems, including:

• Open and closed (recirculating) systems

• Network systems that branch or loop, with no limit on the number of loops

• Pressure driven systems

• Compressor or fan driven systems, including multiple compressor/fans in parallel or in series

• Compressor/fans with variable speed, controlled pressure and controlled flow

• Systems with pressure and/or flow control valves

• Systems with valves closed and compressor/fans turned off

• Heat transfer analysis and system energy balance

• Systems with non-ideal gases

• Systems that experience sonic choking, including multiple sonic choking points

• Systems with non-reacting flow stream mixing and user defined mixtures (with optional Chempak)

• Systems with elevation changes or rotation such as in turbomachinery

• Multiple design cases in a single model file

• Cost calculation of compressor and fan energy usage

AFT Arrow provides hundreds of standard loss models for pipe system components, but also allows you to enter your own loss data. Variable loss models that depend on flow are supported.

AFT Arrow's powerful solution engine is based on standard techniques used for many years in industry. The Newton-Raphson method is used to solve the fundamental equations of pipe flow that govern mass and momentum balance. Solutions are obtained by iteration, and matrix methods optimized for speed are employed to obtain convergence.

AFT Arrow provides two independent solution methods that can be run individually or in combination with each other to allow flexibility and cross-verification of results. In addition, AFT Arrow offers two lumped methods which offer improved computation speed with a slight loss in accuracy. Modeling of low to high pressure and low to high velocity systems can be performed. Sonic capabilities allow modeling of high velocity conditions such as in relief systems.

AFT Arrow can model a large range of gas systems including steam, natural gas, air, and chemical and petrochemical process gases. Support for real gases is offered through several generalized equation of state models or the optional Chempak add-on.

Where to Start

The best place to start learning about AFT Arrow is to work through our examples and video tutorials found in the Arrow Learning Resources.

Add-on Module Capabilities

AFT Arrow has two add-on modules which extend AFT Arrow’s extensive modeling capabilities into new areas.

• The Goal Seek & Control (GSC) module allows the engineer to perform multi-variable goal seeking and simulate control system functions.

• The Automated Network Sizing (ANS) module automates the process of sizing pipes and ducts in a complex network based on required conditions, such as maximum pressure or minimum flow, to reduce cost or weight.

• The Extended Time Simulation (XTS) module allows the engineer to model time varying system behavior.

Who Can Use AFT Arrow

Effective use of AFT Arrow requires a basic understanding of compressible flow theory. Another topic offers a review of compressible flow theory and gives several references of more detailed information. AFT Arrow users should have a working knowledge of all the concepts discussed in Review of Compressible Flow Theory. In some cases it may be advisable that users attend training courses offered by Applied Flow Technology or AFT Arrow recognized authorities.

In addition to familiarity with compressible flow theory, engineers who use AFT Arrow should be familiar with standard industry practice in analyzing gas piping systems.