绝对压力与相对压力 absolute pressure relative pressure 当p>Pb 表压力p p= pe t pb Gage pressure 当p<pb 真空度p p=pb-p Vacuum pressure P pb b绝对压力与相对压力 示意图 当 p > pb 表压力 pe e b p p p = + 当 p < pb 真空度 pv b v p p p = − pb pe p pv p absolute pressure relative pressure Gage pressure Vacuum pressure