AFT xStream is a powerful fluid dynamic simulation tool designed for analyzing high-speed, acoustic transients that occur in steam and gas piping systems. It addresses the significant costs and time associated with design and operational uncertainties by enabling accurate simulation of how steam and gas systems respond to potentially disruptive transient events. The software allows users to precisely simulate high-speed transients, including choked flow conditions, and evaluate overall system response and transient pipe forces after events like steam and gas turbine trips. It can predict transient supply pressures, temperatures, and flows to operating gas compressors and turbines when one trips offline, and simulate tank blowdowns and charging, determining the time required to reach desired pressures. Furthermore, xStream can predict transient pressures and flows resulting from heat exchanger tube ruptures. Users can easily modify system input data, including transient valve positions, compressor operation, control set points, pressures, and temperatures, and initiate transients based on time or specific system events. The tool supports a wide range of fluids such as steam, compressed air, process gases, hydrogen, and natural gas. It helps ensure pressure, temperature, and flow extremes remain within design allowables, determine imbalanced pipe forces for structural support sizing, and troubleshoot existing systems to identify the root cause of operational problems. xStream incorporates a highly accurate steady-state solver for seamless transfer of initial conditions to the transient analysis, utilizing a modified Newton-Raphson matrix iteration and proprietary calculation methods. A specialized Method of Characteristics is employed to solve the transient mass, momentum, and energy equations of pipe flow.

Features & Benefits

• Advanced Transient Simulation
  • Accurately simulates high-speed, acoustic transients in steam and gas piping systems, including choked flow conditions, turbine trips, tank blowdowns, and heat exchanger tube ruptures.
  • Evaluate overall system response and transient pipe forces after steam and gas turbine trips.
  • Predict transient supply pressures, temperatures and flows to operating gas compressors and turbines when one trips offline.
  • Simulate tank blowdowns and charging, and how long it takes to reach desired pressures.
  • Predict transient pressures and flows due to heat exchanger tube ruptures.
  • Easily change system input data including transient valve positions, compressor operation, control set points, pressures, temperatures and more.
  • Initiate transients based on time or events in the system.
• Robust Solver Technology
  • Features a built-in, highly accurate steady-state solver for automatic system initialization and seamless transfer of initial conditions to transient analysis, utilizing a specialized Method of Characteristics for solving transient flow equations.
  • Automatic pipe sectioning based on steady-state acoustic velocities.
• Comprehensive Design & Operational Analysis
  • Enables users to ensure pressure, temperature, and flow extremes are within design allowables, determine imbalanced pipe forces for structural support sizing, and troubleshoot existing systems to identify operational problems.
• Integrated Scenario Management & Reporting
  • Includes a Scenario Manager to track all design variants and operational possibilities within a single model file, complemented by integrated graphing, reporting, and animation tools for visual interpretation.
  • Organize design variants, operating conditions, existing infrastructure, and expansions into a single file.
  • Batch run operating scenarios and export results to Excel.
  • Easily compare design variant input to isolate changes between systems.
  • Quickly review model input from a schematic.
  • Compare transient response in different operating scenarios on a single graph.
  • Animation tools for visual interpretation of complex transient interactions.
• Extensive Libraries & Customization
  • Provides built-in libraries of fluids (including NIST REFPROP and ASME Steam Tables) and fittings, which can be extended and customized.
  • Select pipe materials, sizes, type, and schedule from built-in or custom databases.
  • Use built-in handbook data and heuristics for common component losses.
  • Collect and catalogue common component and pipes into custom libraries.
  • Chempak™ add-on utility provides a thermophysical database of almost 600 gases, allowing definition of non-reacting pre-mixtures and simulation of dynamic flow mixing.
• Seamless Integration & Visualization
  • Generates force imbalance files that can be automatically read into industry-standard pipe stress dynamic models (CAESAR II, ROHR2, AutoPIPE, TRIFLEX), and offers both 2D flow diagram and isometric view interfaces.
  • 2D flow diagram or isometric view interface.
  • Reduce redundant specification by importing your model file.
  • Draw your model as an isometric or on top of an aerial photography background.
  • Quickly make changes to common pipes and components with Global Edit.
• Pulsation Frequency Analysis Add-On Module
  • An optional software extension tool that helps identify pipe acoustical frequencies to avoid resonance from excitation, particularly in systems with reciprocating compressors.