Modelling of a low-temperature differential Stirling engine

A full theoretical model of a low-temperature differential Stirling engine is developed in the current paper. The model, which starts from the first principles, gives a full differential description of the major components of the engine: the behaviour of the gas in the expansion and the compression spaces; the behaviour of the gas in the regenerator; the dynamic behaviour of the displacer; and the power piston/flywheel assembly. A small fully instrumented engine is used to validate the model. The theoretical model is in good agreement with the experimental data, and describes well all features exhibited by the engine.

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The structure of the Cincinnati arch as determined by short period Rayleigh waves

Bulletin of the Seismological Society of America ◽

10.1785/bssa0590010399 ◽

1969 ◽

Vol 59 (1) ◽

pp. 399-407

Author(s):

Robert B. Herrmann

Keyword(s):

Experimental Data ◽

Theoretical Model ◽

Layer Thickness ◽

Rayleigh Waves ◽

Layer Model ◽

Depth Data ◽

Short Period ◽

Best Fitting ◽

Good Agreement

Abstract The propagation of Rayleigh waves with periods of 0.4 to 2.0 seconds across the Cincinnati arch is investigated. The region of investigation includes southern Indiana and Ohio and northern Kentucky. The experimental data for all paths are fitted by a three-layer model of varying layer thickness but of fixed velocity in each layer. The resulting inferred structural picture is in good agreement with the known basement trends of the region. The velocities of the best fitting theoretical model agree well with velocity-depth data from a well in southern Indiana.

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A thermodynamic description of metastable c-TiAlZrN coatings with triple spinodally decomposed domains

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb161017001z ◽

2017 ◽

Vol 53 (2) ◽

pp. 85-93 ◽

Cited By ~ 2

Author(s):

J. Zhou ◽

L. Zhang ◽

L. Chen ◽

Y. Du ◽

Z.K. Liu

Keyword(s):

Experimental Data ◽

Phase Equilibria ◽

First Principles ◽

Thermodynamic Description ◽

Quantitative Description ◽

Experimental Phase Equilibria ◽

Free Energies ◽

Calphad Technique ◽

Important Input ◽

Good Agreement

A critical thermodynamic assessment of the metastable c-TiAlZrN coatings, which are reported to spinodally decompose into triple domains, i.e., c-TiN, c-AlN, and c-ZrN, was performed via the CALculation of PHAse Diagram (CALPHAD) technique based on the limited experimental data as well as the first-principles computed free energies. The metastable c-TiAlZrN coatings were modeled as a pseudo-ternary phase consisting of c-TiN, c-AlN and c-ZrN species, and described using the substitutional solution model. The thermodynamic descriptions for the three boundary binaries were directly taken from either the CALPHAD assessment or the first-principles results available in the literature except for a re-adjustment of the pseudo-binary c-AlN/c-ZrN system based on the experimental phase equilibria in the pseudo-ternary system. The good agreement between the calculated phase equilibria and the experimental data over the wide temperature range was obtained, validating the reliability of the presently obtained thermodynamic descriptions for the c-TiAlZrN system. Based on the present thermodynamic description, different phase diagrams and thermodynamic properties can be easily predicted. It is anticipated that the present thermodynamic description of the metastable c-TiAlZrN coatings can serve as the important input for the later quantitative description of the microstructure evolution during service life.

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Theoretical Model of the Spanwise Mixing Caused by Periodic Incoming Wakes

Volume 1: Turbomachinery ◽

10.1115/94-gt-153 ◽

1994 ◽

Author(s):

K. Imanari

Keyword(s):

Experimental Data ◽

Theoretical Model ◽

Turbulent Diffusion ◽

Axial Flow ◽

Single Stage ◽

Mixing Coefficients ◽

Predicted Values ◽

Good Agreement ◽

Axial Flow Compressors

A theoretical model is proposed for the spanwise mixing caused by periodic incoming wakes in the context of turbulent diffusion in axial-flow compressors prior to repeating-stage conditions. The model was used to predict the spanwise mixing coefficients across a stator of a single-stage compressor without IGVs. The correctness of the theory was demonstrated by the results that the predicted values were in good agreement with the associated experimental data.

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