Absoluutrõhk

Absoluutrõhk refers to the pressure of a system measured relative to a perfect vacuum. A perfect vacuum is considered to have zero pressure. Therefore, absolute pressure represents the total pressure exerted by a fluid or gas, independent of any external atmospheric pressure. This is in contrast to gauge pressure, which measures the pressure difference between a system and the surrounding atmospheric pressure. For example, a tire pressure gauge measures gauge pressure. If the gauge reads 30 psi, the absolute pressure inside the tire is approximately 30 psi plus the current atmospheric pressure.

Absolute pressure is often denoted by P_abs. The relationship between absolute pressure, gauge pressure (P_gauge), and atmospheric pressure (P_atm) is typically expressed as P_abs = P_gauge + P_atm. This concept is crucial in various scientific and engineering applications, including thermodynamics, fluid mechanics, and vacuum technology, where precise pressure measurements are essential for accurate calculations and system operation. Understanding the distinction between absolute and gauge pressure is fundamental to correctly interpreting pressure readings and designing systems that function under specific pressure conditions.