Altair Flow Simulator 2022.2 Release Notes

Highlights

Added grid for symbol placement in the modeling window.
Disk Pumping element.
Renamed the Advanced Orifice to Advanced Tube to better reflect its use cases.

New Features

Grid for Symbol Placement: A grid can be used for symbol placement when creating a flow and thermal network. This helps make an evenly spaced network that looks better on screen. The Activate Grid option must be selected for the symbols to snap to the closest grid intersection. Hide the grid by selecting the Show Grid option.
Note: The location of the symbols does not affect the flow or thermal solution for most modeling methods (same as previous versions).

Figure 1. Grid for Symbol Placement
Disk Pumping Element: Flow is entrained radially outward along a rotating disk. An element has been added to simulate this affect. It can be used in the secondary air systems of gas turbine engines.

Figure 2. Disk Pumping Element
Tooth-By-Tooth Labyrinth Seal Element (BETA): A labyrinth seal element has been added that is like the Vermes Seal element. The new element uses a tooth-by-tooth marching scheme to calculate the pressure in each pocket using the seal flow rate and calculated losses. The Vermes Seal element uses a global equation with just the seal upstream pressure, downstream pressure, and losses to calculate a flow rate. The Vermes Seal pocket pressures are estimated. The new element is considered a BETA release until more testing is completed.

Figure 3.

Enhancements

Heat Exchanger Rotation

Generic and Plate-Fin Heat Exchanger can now be rotated to align the hot (red) side and cold (blue) side with the appropriate elements.

Advanced Orifice Renamed Advanced Tube

The Advanced Orifice was renamed Advanced Tube to better reflect its use cases. The element is located under the Compressible Tubes instead of the Orifices in the element library. The element itself has not changed except for the new annulus input option. The Advanced Tube is used for compressible gas applications and is similar to the standard Compressible Tube. Advantages of the Advanced Tube over the standard Compressible Tube include no limit on axial stations and the ability to split the tube wall into different segments (like an inner surface and outer surface of an annulus).

Two Diameter Inputs for Tube Annulus

The Compressible Tube, Advanced Tube, and Incompressible Tube now have an inner and outer diameter input when the tube shape is an annulus. The diameters can be constant, linear, and supplied for each station.

Vermes Seal Improvements

Three changes have been made to the Vermes Seal element to improve its accuracy (comparison to test data).

New option added for clearance factor (KFAC). The Bell-Bergelin Advanced option was added to account for the tooth Reynolds number (Re) not close to 10,000. The Tooth Re can be found in the *.res file. Bell-Bergelin Advanced is the default option for new elements, but old elements still use the Bell-Bergelin Simple option.

Figure 7. Clearance Factor Option
New option added for the honeycomb leakage multiplier (HCMULT) for straight seals. The new option more accurately follows the reference paper and is used automatically by old and new elements.

Figure 8. Honeycomb Multiplier Option
The mass flow for a choked seal has been modified. The seal mass flow rate from the Vermes equation is now checked against a flow rate from a choked flow calculation over the last tooth. The choked flow rate is used if it is lower than the flow rate from the Vermes equation. Also, the Cd used in the choked flow calculation is no longer the same Cd as that used in the Vermes equation.

Figure 9.

FI Cdcomp Element Added Equation Control

The Cdcomp element calculates a discharge coefficient (Cd) based on geometry and flow. There are six effects that go into this calculation. These effects can be controlled with user input. The default options use the same equations as previous versions. The new control allows you to remove the effect, pick an alternate built-in equation, or use a custom equation. Use the Customization Manager to create the custom equation in either Python or Fortran.

Display Options Window Update

The Display Options window controls the text displayed in the modeling window. This window has been modified to make it easier to use.

Tube Centerline Coordinates

The Compressible Tube, Advanced Tube, and Incompressible Tube elements have a new input for coordinates of each tube station. These coordinates facilitate the mapping of tube station data from Flow Simulator to other solvers. The Flow Simulator coupling to other solvers is under development and will be released in future versions. The station coordinates are generated when a surface is selected for automatic element creation. These coordinates are not used by the solver in this release.

PID Controller Transient Convergence Controls

New controls added for convergence of PID controllers during a transient. These controls determine what happens when all convergence criteria are met except for the PID controller convergence criteria. It is difficult to converge a PID controller to a tight criterion for all timesteps. The PID controller may be lagging and need a few timesteps to “catch-up” to the target value. These controls allow the solver to continue to the next timestep, even if the controller is not converged. These setting do not affect PID controllers used with steady-state analysis.

Thermal Conductors and Nodes Using Liquids and Gasses

This version allows thermal conductors and thermal nodes to use liquid and gas properties as well as solids. This can be useful if a conductor is used to represent a small air gap. Another application is a thermal node representing an enclosed thermal volume of liquid (if the volume is not enclosed, a fluid accumulator is a better choice).

Improvements to Element Creation Using Geometry

Several improvements have been implemented to create elements directly from geometry. This tool still works best for piping systems that use tubes and bends. The improvements include setting element flow direction based on the location of the surface selection (pick a surface near the inlet end), and improved tube diameter extraction from the element surface. Also, any element type can be created at a surface centerline by pressing the Alt key while dragging the element from the element library.

Boundary Chambers - New Options for Temperature, Swirl, and Quality

New options to pass temperature, swirl, and fluid quality through a boundary chamber have been added. These options can be used for closed loop networks and for models with cavities on boundary inertial chambers.

Reverse Element Direction with Space Bar

Previous versions used a double-click on an element to reverse its direction. This was changed to avoid conflicts with other items using a double-click. In 2022.2, reverse an element's direction by pressing the space bar while selecting the element symbol.

Element Arrow Size Control

The element arrow size can be controlled under Settings > User Setting > Graphics.

Known Issues

The following known issues will be addressed in a future release as we continuously improve software performance:

The new controller interface does not work with controllers that have two relations. For example, a 1D table and Python script in the same controller.

Resolved Issues

Disappearing custom correlation inputs when renumbering an element.
Orifice element radius changes to 0.0 after reversing element.
Problem with some equations not working in the variable editor.
Added some missing or incorrect items to the XML output file for cavity flows.
Added detail to the plate-fin heat exchanger image in the Property Editor.