一圓柱形機軸在固定的軸承中勻速轉(zhuǎn)動。軸徑d=20cm,軸承寬b=20cm,潤滑油粘度μ=0.2Pa·s,軸承轉(zhuǎn)速為n=150r/min。設(shè)間隙分別為δ=0.8mm,0.08mm,0.008mm時,求所需轉(zhuǎn)動功率。