Thermoacousticsbaner

Thermoacoustics

The central source for information on thermoacoustics research at the Laboratory.

Educational and computational resources, links to news, publications, and information on research and development of thermoacoustic engines, refrigerators, and mixture separators.

Thermoacoustics is the interaction between temperature, density and pressure variations of acoustic waves. The groundbreaking Thermoacoustics research performed at Los Alamos National Laboratory focuses on applying this to create next generation propulsion systems for space travel, refrigeration systems, and gas seperation systems.

Thermoacoustics Textbook

This new edition is available from Springer, as a hardcover book and an ebook.  If you are located outside the US, a notice will appear at the top of the page directing you to a version of Springer’s website optimized for your own country. That page will display pricing in your local currency. You can also manually change the country from the drop-down list at the top right of the page.

For students and staff at universities and other institutions with a subscription to Springer’s eBook Package in Physics and Astronomy, you can click on “Access this title on SpringerLink - Click here” to download the eBook for free and/or purchase a low-cost, black-and-white paperback for individual use.

To obtain the computer animations used to illustrate points in the book, for either the first or second edition, download files from Springer or LANL. 

To fully explore the textbook and examples within it, also download the computer code DeltaEC.

DeltaEC

Design Environment for Low-amplitude ThermoAcoustic Energy Conversion (DeltaEC) is software that can predict how a given thermoacoustic apparatus will perform, or can allow the user to design an apparatus to achieve desired performance.

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. 

Please email our team for access to the software.

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.

Revision History

  • 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.
  • 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.
  • 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.
  • 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!

TransitionGuide(ver 5 to 6).pdf

Please help us by reporting difficulties via the contact us button on our webpage, or by emailing address@lanl.gov.

Describe the problem, the DeltaEC version number, and whether you are running it on Windows 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.

Publications

Within each category, these recent journal articles and conference papers are listed in reverse chronological order.

Clicking on a link takes you to that journal's website, where you might only have access if the journal recognizes you or your institution as a subscriber. If you can't get access to a journal please contact our staff to request a pdf reprint of the article.

  • "Operation of thermoacoustic Stirling heat engine driven large multiple pulse tube refrigerators," Bayram Arman, John Wollan, Vince Kotsubo, Scott Backhaus, and Greg Swift, submitted to the proceedings of the 13th International Cryocooler Conference. Kluwer Academic/Plenum Publishers holds the copyright to this paper.
  • "Thermoacoustics for liquefaction of natural gas," G. W. Swift and J. J. Wollan, GasTIPS, Volume 8, Number 4, pages 21-26 (Fall 2002). (Erratum: page 23, column two, under the heading "How the refrigerator works": The first word of the 23rd line in that paragraph should be "falls" instead of "rises.")
  • "Development of a thermoacoustic natural gas liquefier," J. J. Wollan, G. W. Swift, S. N. Backhaus, and D. L. Gardner, AIChE Meeting, New Orleans LA, March 11-14, 2002.
  • "Thermoacoustic refrigeration --- A stirring concept for offshore associated gas liquefaction," W. C. van Wijngaarden, Monetizing Stranded Gas Reserves Conference, Houston TX, December 7-9, 1999.
  • "John Malone and Liquid Thermodynamics," G. W. Swift, issue 2010-3 of Stirling Machine World, edited by John Corey.
  • "Interactive analysis, design, and teaching for thermoacoustics using DeltaEC," W. C. Ward, G. W. Swift, and J. P. Clark, talk given at the spring 2008 meeting of the Acoustical Society of America (Paris). Abstract available at Journal of the Acoustical Society of America 123, 3546 (2008).
  •  "Thermoacoustic energy conversion," G. W. Swift, Chapter 7 of the Springer Handbook of Acoustics, edited by Thomas Rossing (Springer, 2007).
  • "New varieties of thermoacoustic engines," S. N. Backhaus and G. W. Swift, Paper number 502, Proceedings of the Ninth International Congress on Sound and Vibration, Orlando FL, July 8-11 2002.
  • "Separation of gas mixtures by thermoacoustic waves," D. A. Geller, P. S. Spoor, and G. W. Swift, Proceedings of the 17th International Congress on Acoustics, Rome, 2-7 September 2001; Volume 1, Part A, Session "Thermoacoustics," pages 16-17.
  • "Thermoacoustics," G. W. Swift, McGraw-Hill Encyclopedia of Science and Technology, 9th edition, Volume 18, 353-355 (2002)
  • "Thermoacoustics: A unifying perspective for some engines and refrigerators," G. W. Swift, graduate-level textbook, available at ASA Books.
  • "The power of sound," S. L. Garrett and S. Backhaus,  American Scientist 88, 516-525, (2000).
  • "Streaming in thermoacoustic engines and refrigerators," G. W. Swift, Nonlinear Acoustics at the Turn of the Millennium: Proceedings of the 15th International Symposium on Nonlinear Acoustics, edited by W. Lauterborn and T. Kurz, 105-114 (American Institute of Physics, Melville NY, 2000).
Loop Standingsmall

Educational Animations

These are computer animations of thermoacoustic processes described in Thermoacoustics: A Unifying Perspective for some Engines and Refrigerators. Select the version below that is compatible with your computer, download and unzip the file, and look for a readMe file if you need further instructions.

These animations were created in the late 1990s with Microsoft QuickBASIC. We converted them to Visual Python in the early 2010s. The physics is the same in both versions, but the Visual Python version is prettier.

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.

Questions about Thermoacoustics?

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