水的粘度计算表

1、温度T粘度卩Pa 或N s m-2温度T粘度卩Pa s或N s m-2KK0X10"3X10"31X10"321X10"32X10-322X10-33X10"323X10"34X10 -324X10 -35X10-325X10-36X10"326X10"37X10"327X10"38X10"328X10"39X10 -329X10 -310X10"330X10"311X10"331X10"312X10"332X10"

2、313X10 -333X10-314X10 -334X10-315X10 -335X10-316X10 -336X10-317X10-337X10-318X10-338X10-319X10-339X10-320X10-340X10-3水的物理性质温度t/°c饱和蒸气压p/kPa密度P/kg m-3焓H/kJ kg-1比定压热容cp/kJ kg-1 K-1导热系数入/10 -2W m-1 K-1粘度卩/10 -5 Pa s体积膨胀系数a/10 -4 K-1表面张力o/10 -3N m-1普兰德数Pr00102030405060708090100110120130140150160170

3、180190200210220230240250260270280290300310320330340350360109370264F3? Viscosity decreases with pressure(at temperatures below 33 C)Viscous flow occurs by molecules moving through the voids that exist between them. As the pressure in creases, the volume decreases and the volume of these voids reduces

4、, sonormally increasing pressure increases the viscosity.PFE 5a a%枕-e. a. a _ a '4【中c軒缶bha0斗町009200 眾.400"认 600 i 800 A 1000Pressure, MPa卍 <L0 & %- %Water's pressure-viscosity behavior can be expla ined by the in creased pressure (up to about 150 MPa) caus ing deformati on, so re

5、duc ing the stre ngth of the hydroge n-bon ded n etwork, which is also partially resp on sible for the viscosity. This reduct ion in cohesivity more than compensates for the reduced void volume. It is thus a direct consequence of the betwee n hydroge n bonding effects and the van der Waals dispers i

6、on forces in water; hydroge n bonding prevaili ng at lower temperatures and pressures. At higher pressures (and den sities), the betwee n hydroge n bonding effects and the van der Waals dispersi on forces is tipped in favor of the dispersi on forces and the rema iningare stron ger due to thecloser p

7、roximity of the con tributi ng oxyge n atoms . Viscosity, the n, in creases with pressure. The dashed line (opposite) in dicates the viscosity mini ma.The variation of viscosity with pressure and temperature has been used as evidence that the viscosity is determined more by the extent of hydrogen bonding rather than hydrogen bonding strength.Self-diffusion is also affected by pressure where (at low