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I-Ui. 5.11). 1-llfect of tlie swcpt-volume ratio k on cycle power. The figure nhowj, the effect on the non-dimensional power parameter /V(|»nlll, V',) of variation in the swcpt-volume ratio k, with constant values of the temperature 7 - 0.25 and 0.5, phase nngle o = 90°. and dend-volume ratio X = I-(J. On the two curves shown, for different values of r. the maxima do not occur at the same value of k. There is no single 'best' value for k since the optimum value depends on the combinations <». r, and X.

I-Ui. 5.11). 1-llfect of tlie swcpt-volume ratio k on cycle power. The figure nhowj, the effect on the non-dimensional power parameter /V(|»nlll, V',) of variation in the swcpt-volume ratio k, with constant values of the temperature 7 - 0.25 and 0.5, phase nngle o = 90°. and dend-volume ratio X = I-(J. On the two curves shown, for different values of r. the maxima do not occur at the same value of k. There is no single 'best' value for k since the optimum value depends on the combinations <». r, and X.

shows I he effect of the phase angle a on cycle power. The power parameter is remarkably insensitive to changes in the phase angle over an extended range Irom 60° to 120° of crank rotation, For the particular assumed conditions the optimum value was between 90" and I 15°.

A three-dimensional presentation is given in Fig. 5.13 of the variations in engine-power parameter with change in both phase angle « and swcpt-volume ratio k. for constant values of r and X. This presentation results in the generation of a solid surface. Any changes in r or X cause the generation of a series of similar, but different, overlaying surfaces. I lie apex of the surface represents the maximum value of lite power parameter, and occurs at the optimum combination of swcpt-volume ratio and phase angle, for the given values of t and A'. Fig. 5.13 shows Iwo surfaces, generated with the different power parameters P/(pcim VT) and Flno„. For these two surfaces, the apex occurs at different combinations of phase angle and swcpt-volume ratio. In the case ol the surface drawn for the power parameter 7,inn„ = P/A/KT<. <vopl - 0.45 tt rad and Kopt = 2.9. In the case of the surface drawn for the power parameter Pni(W = l3/{p„m* VT), «,,,„ =0.54 7r rad and K„pl - 0.74. A simple explanation for litis strange phenomenon is that optimization of design 011 the basis of the power parameter /',„„„ results in a machine configuration that makes the best possible use of a limited mass of workine fluid. Oolimization of

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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