The Acoustical Behavior of Contra-Rotating Fan

<table class="fixed-width table-group" id="tab3"><tr><td><table class="table"><colgroup><col style="width:6.85em"/><col style="width:5.02em"/><col style="width:5.51em"/><col style="width:5.48em"/><col style="width:4.18em"/></colgroup><tr><td class="thead-hr" colspan="5"><hr/></td></tr><tr class="thead"><td class="align_left">Spacing</td><td class="align_center">0.5 chord</td><td class="align_center">0.65 chord</td><td class="align_center">0.75 chord</td><td class="align_center">1 chord</td></tr><tr><td class="thead-hr" colspan="5"><hr/></td></tr><tr><td class="align_left">The highest efficiency (%)</td><td class="align_center">65.1</td><td class="align_center">68.59</td><td class="align_center">73</td><td class="align_center">70.88</td></tr><tr class="table-tr"><td colspan="5"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>The efficiencies of four axial spacing points.</div>

Mathematical Problems in Engineering

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Table 3

Table 3: The Acoustical Behavior of Contra-Rotating Fan 