第二章矿井空气流动基本理论

1、举例：举例：18的空气，饱和水蒸气量为的空气，饱和水蒸气量为sat=0.01536kg/m3，30时，时，sat=0.03037kg/m3结论：绝对湿度只能说明空气中实际含有水蒸气量，并不能说明其结论：绝对湿度只能说明空气中实际含有水蒸气量，并不能说明其饱和程度。饱和程度。在井下某巷道用风扇式湿度计测得，风流的干球温度为25.6,湿球温度为23.5。求算风流的相对湿度?解： 利用内插法求得相对湿度=83.825.623.52.1ttt 23.5 84.5 8184.5 818122.52.1 2.5V ydvdyFS0.3780.003484(1)satPPTP.d avabPa真空P0Pbh

2、a(+)hb(-)P0dzi风表的使用风表的使用abPa真空真空P0Pbha(+)hb(-)P0Pathvhat(+)hvhbt(-)Pbt抽出式通风抽出式通风压入式通风压入式通风hP0izP0 ihP0izP0 iz zP P0 i0 ih ht th hi ih hv vz zP P0 i0 ih h0 00 0zP0 i100Pa150Pahvz1z200p1、v1、u1p2、v2、u2qLRqR211111Pv1 1:.u2g Z断面总能量222222Pv22:.u2g Z断面总能量2222 2R2Pv.uL2g Z211111Pv.u2Rg Zqq2R211qq=uuPdv22221

3、221121111PPPPd PPddPvvvvv22212R121vvLdPg Z22vZ 11221dP=dPv12122112lnPlnPlnPlnPdlnPlnPn=dlnlnlnlnlnlnvvvv221212R1212PPvvnLg Zn122Z221212R1212PPvvnLgZn122tZL121212PPPPnn1m121211221212111222PPPPPPPnlnPPPn1P /lnP/m221212R12PPvvLg Z22mZ221212R12mPPvvLg Z22ZLt2212R12m12vvhPPgZ22mZ123001po1212122EgdZgZm1po

4gdZmmgZgZ2212vv22m22121 212vv22vh2212R1212m11m22vvhPPgg22ZZ23ssv23dsds2KvvvS2uuuS2212R1212m11m22tvvhPPgg+H22ZZ2212111112222223333332R123R13vvQZPQZP22vQZPQhQh2mmmggg31222121212121212-22RmvvhP PZZgZ1-Z21231106657.60.378 0.7 17040.00348411.2841/288.15106657.6kg m32101324.720.378 0.8 23370.0

5、0348411.1958/293.15101324.72kg m1212lnPlnPln106657.6-ln101324.72n=0.72lnlnln1.2841 ln1.1958221212R1212PPvvnLg Zn 122Z220.72106657.6101324.725.559.814000.72 11.28411.19582 2212R12m12vvhPPgZ22mZ3121211221212111222PPPP1.23877 kg/mPPPnlnPPPn 1P /lnP /m121.239952m或012345678910P0压力压力Pa流程流程扩散器扩散器HthR02hR78hR7-10hR7-10测得相对静压，断面动压，断面积及与风道同标高的大气压，计算出各点的相对全压 为什么断面大处动压小？hR23=? RijijvivjtitjhPPhhPPtitjhh1099抽出式通风方式抽出式通风方式压入式通风方式压入式通风方式506651001234b0c0d0a1a2b2c2a0(a)b (b1)c(c1)dd