DeltaEC

DeltaEC numerically integrates a one-dimensional wave equation appropriate to a user-defined geometry in a user-selected gas or liquid. DeltaEC is capable of handling complex geometric configurations and specialized acoustic elements including resonators, duct networks, and complete thermoacoustic engines, electroacoustically driven thermoacoustic refrigerators, and thermoacoustic mixture separators.

Source code for DeltaEC is not available to the public. We have instead made executable code available for common computers. Compiled DeltaEC executable files, example files, and release notes are available below.

A two-page introduction (pdf) to DeltaEC's decade-old core capabilities is available, and the current Users Guide (pdf) (which is also included in the installation package) explains current capabilities. The Users Guide requires Adobe Acrobat Reader, version 6 or later.

Experienced users can review the recent revision history and a list of known bugs, below.

This program was prepared by Los Alamos National Security, LLC at Los Alamos National Laboratory (LANL) under contract No. DE-AC52-06NA25396 with the U.S. Department of Energy (DOE). All rights in the program are reserved by the DOE and Los Alamos National Security, LLC. Permission is granted to the public to copy and use this software without charge, provided that this Notice and any statement of authorship are reproduced on all copies. Neither the U.S. Government nor LANS makes any warranty, express or implied, or assumes any liability or responsibility for the use of this software.

For Windows XP, Vista, 7, 8, and 10, and perhaps future versions of Windows: DeltaECInstallerV64b2pt7-Windows.exe

Running the installer as an administrator puts DeltaEC into its own folder inside the ProgramFiles(x86) folder, complete with the Users Guide. File names ending in .out should automatically become associated with DeltaEC. Shortcuts should appear on your desktop and in the Start menu. Example files will be installed in a folder of your choice.

If you don't run the installer as an administrator (e.g., by right clicking on the installer and selecting "Run as administrator"), you may find that you don't have the authority to put anything in c:\ProgramFiles(x86).

A good location for the "DeltaEC Examples" folder can be the installation folder itself, from which you can copy the example files to another, temporary working folder when using them. Other good locations for the "DeltaEC Examples" folder include c:\Users\myusername\Documents (which is equivalent to My Documents in Windows Explorer) and c:\Users\Public\PublicDocuments (which is equivalent to Documents in Windows Explorer).

For Mac with Intel (i86) processor: DeltaEC_Mac_Intel_6-2b3.tgz

For Mac/PowerPC (Motorola processor): DeltaEC_Mac_PPC_6-2b3.tgz

These DeltaEC Mac versions are built with Mac OS X (presently, 10.4.11), as 32-bit applications.  Builds are not created as Universal binaries due to FORTRAN compiler version restrictions, so pick the correct version above.

To install DeltaEC on a Mac, just unpack everything to the folder in which you want DeltaEC to reside. 

Alternatives for Windows 98, 2000, and NT, and very old Macs:

For old Windows computers, try DeltaECInstallerV63b11-Win2k.exe. See revision history for the shortcomings of version 6.3 compared with version 6.4.

DeltaE 5.5b6 (dating to 2007) for MS-DOS or MacIntosh is still available to users who prefer the old user interface.  It has only one known bug, in the calculation for PISTBRANCH. However, DeltaE 5.5b6 has a very primitive user interface and no steady-flow or mixture-separation capabilities.

From 5.5 to 6.1, 2008:

TransitionGuide(ver 5 to 6).pdf

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From 6.1 to 6.2, early 2009:

* Fixed a bug that sometimes scrambled the order of headers in ip files. The variable names will now always match up with the numbers.

* Fixed some bugs involving use of multiple user-defined gases and/or solids.

* Allowed cancellation from an incremental-plot run that gets lost, and added a "rewind from incremental plot" feature so you can click on any point in the graph of an incremental plot and go to that state immediately.

* Improved "schematic" display, even including a phasor display in it.

* Added MIXT** segments, having simultaneous nonzero dTm / dx and dnL / dx (for those who want to do mixture separation in a temperature gradient).

* Allowed better incremental plotting with interlinked models.

* Added a new chapter to the Users Guide, "Good Design Habits."

* Fixed lots of little problems and annoyances that we hope non-Los Alamos users never encountered!

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From 6.2 to 6.3, early 2012:

* New state-plot features: magnitude and phase of p1 and U1 phasors, in addition to real and imaginary parts. Similarly, display Z=p1/U1. Also segEndMarks shows ranges for what would otherwise be overlapping numbers. Also log axes.

* Improved MasterPlot (incremental plotting with multiple, linked models).

* Improved Schematic View, including phasors.

* Added more flexibility and user control to target "normalization mode," to help target convergence in some models.

* Improved compatibility with Windows Vista and 7.

* New appearance and behavior of printing.

* Increased pathname length allowed for BLKDATA segments.

* Improved warnings about guesses preceding targets, sameas preferably looking upstream, avoiding circular sameas, etc.

* Fixed calculation error in PISTBRANCH segment. (Factor of 2 in Bessel-function term in real part of Z.) No change to Users Guide.

* Change how f-sub-kappa is calculated for turbulent flow in VX** segments, to avoid second-law violations that occurred in some corners of parameter space in version 6.2.

* Many small display improvements and interface speed-ups.

* Improved RPN segment interface that color-highlights the tokens associated with each result. Semicolons allowed in RPN strings for human readability.

* Extended temperature range for accurate cp, gamma, and Prandtl number for carbon dioxide.

* A new solid, "celcor," in the default thermophysical library.

* Fixed bug when user changes from built-in gas or solid to tpf-based gas or solid.

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From 6.3 to 6.4, mid 2016:

* Sameas: To save typing most of the time, the default sameas choice in the parameter-edit dialog is now an upstream input parameter with similar description (except CONE Final parameters default downstream); and DeltaEC warns if a sameas has mismatched units (ignoring blank units).

* Flip: By highlighting a block of segments and right-clicking, it is now possible to flip the order of those segments. Physical segments are strictly flipped. An attempt is made to put RPN segments in intelligent locations.

* SYSEXEC: This new segment type allows sending parameters from midstream in a DeltaEC integration to an external program, running that program, and returning results of the external program to DeltaEC before resuming integration. Can be used to explore alternatives to DeltaEC's built-in segment calculations.

* Changed the smoothing function F in JOIN, to cure a previously undiscovered unphysical case.

* Made tiny changes in roughness calc in turbulent DUCTs, for consistency with Users Guide references.

* Added ds (delta_kappa_solid) to RPN tokens.

* Enabled the ability to set solidtype sameas.

* Improved plotter's ability to recognize a 2-d plot, and improved plotter display defaults.

* Fixed display of nL in UNION, and fixed occasional lack of sameas indicator in UNION targets.

* Fixed many problems with BLKDATA handling.

* Improved warnings about sameas or RPN address that tries to connect to itself, whether directly or through a chain.

* Fixed RPN output color match to command-string color for a< >b .

* In RPN cmdstr highlighting, changed one of the faint blue colors to a faint yellow.

* Tolerate RPN commands getting too long when number of digits in segment numbers increase.

* Fixed VOLUME segment so its address pointers change when other segs are inserted or deleted, or when blocks of segments are copied.

* Fixed display and disk writing of VOLUME segment so extended comment field is allowed.

* Fixed bug: Cutting multiple segments that included a BEGIN or TBRAN was cutting all downstream leg members, even those outside the cut zone.

* Fixed crash when killing, copying, or cutting a segment that is the master of a length special mode.

* Prevent meaningless display of a cleared target that still contained sameas.

* Allow DuplicateSeg to work on SURFACE, JOIN, ANCHOR, INSULATE.

* Many small improvements to the Users Guide, including better indices, better discussion of radiation impedance of an opening to room air, and discussion of the zero of time phase.

* Added example file of a linear alternator having both a specified electrical load impedance and piston blow-by leakage. Added example file of a traveling-wave loop.

* Modified installer for compatibility with Windows 7, 8, and 10.

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From 6.4b2.3 to 6 .4b2.7, late 2017:

* List Linkages: This new feature shows which parameters are linked to a selected parameter, via sameas, master-slave, and RPN calculations. It also displays RPN calculations in either parentheses notation or RPN notation.

* RPN improvements: Add operation ‘avg’. Allow inter-model linking to complex numbers. Improve color alignment for a<>b operation.

* CONSTANTS: Allow user to edit the desc parameters, up to 12 characters.

* Heat exchangers with nonzero steady flow: Eliminate FracQN from HX, TX, SX, PX.

* Interlinked models: Allow rewind from a Multi-model plot.

* Rewind from plot or multi-model plot: Improve behavior when model has RPNs depending on downstream output variables.

* Plotter: Improve handling of Not-A-Number.

* Fix a printer bug that affected use on many computers.

* Improve how line feeds are handled in segment Comment fields.

Please help us by reporting difficulties to the email address at the main Los Alamos thermoacoustics web page. Describe the problem, the DeltaEC version number, and whether you are running it on a pc or a Mac. Attach a minimal test file demonstrating the problem, if possible. If DeltaEC gave you a message about the problem, please send it to us. Most such messages are recorded in DeltaEC.exe.log, which you can find in DeltaEC's installation folder or other location as described in the Users Guide.

Known bugs, DeltaEC version 6.4b2 for Windows:

* DeltaEC's built-in printer works very badly. Please use notepad or something similar to open a *.out file and print it.

Known bugs, DeltaEC version 6.2b3 for Macs:

In addition to the bugs listed above for 6.3b11, read the "6.2 to 6.3" and "6.3 to 6.4" parts of the revision history.