附件24.2 Chapter2 Fundamental Hydraulic Fluid Mechanics 2.The definition of pressure (1)Absolute pressure (2)Relative gauge pressure:The pressures measured by a pressure gauge are all relative pressure (3)Vacuum (negative pressure) The units of pressure and relations between different pressures 1Pa=1N/m2:1bar=1X103Pa=1X109N/m2; 1at=1kgf/cm2=9.8×104N/m2:1mH,0-9.8×103N/m2 1mmHg=1.33X103N/m2 The relationship of three pressures is shown in Fig.2-5 Hrorog List Uperdks Dornveards Peciam Edit Chapter2 Fundamental Hydranlic Fluid Mechanies -p>Pa Gauge pressure (表压力) p<pe A时空 Fig.2-5 absolute,relative and vacuum pressure 附件 24.2 14