(3)作出该级的热力过程线并标出各量。 解:
c12932?hn???47.56 KJ/Kg 3222?10?2?103?0.95*2w2w115721582?hb?????3.418KJ/Kg 3323232?102?10?0.882?102?10?(1)?m??hb3.418??0.07 *3.418?47.56?hn??hb2222(2)u?w2?c2?1572?62.52=144 m/s
c1?u2?w12932?1442?1582=160 ?1?arccos?arccos2c1u2?293?14422?2?arcsinc262.5?arcsin?260 w2157*喷嘴损失为?hn???hn1??2?47.56?1?0.952=4.64 KJ/Kg
?2???w2t178.422动叶损失为?hb??1???1?0.882?3.59 KJ/Kg 32?1032?10????余速损失为?hc2?c262.52???1.95 KJ/Kg 2?1032?1032轮周损失为:?hn???hb???hc2??4.64+3.59+1.95=10.18KJ/Kg 轮周力为:
Fu?G?c1cos?1?c2cos?2??30?293cos160?62.5cos900=851N (3)热力过程线为:
??*?hn P1 *?ht ?hn? ?hb P2
?hb? h ?hc2?
s
9.已知汽轮机某级喷嘴出口速度c1=275m/s,动叶进、出口速度分别为w1=124m/s、
w2=205m/s,喷嘴、动叶的速度系数分别为?=0.97, ?=0.94,试计算该级的反动度。 解:
c1tc12752=40.187 KJ/Kg ?hn???2?1032?103?22?0.972?103*22w2tw22052=23.78 KJ/Kg ?hb???323232?102?10?2?10?0.94*22w11242=16.1 KJ/Kg ?hb??hb??23.78?332?102?10*2?m??hb16.1??0.29 *?hb??hn16.1?40.18