Glossary
to accompany
Thermodynamics: An Engineering Approach, 5th edition
by Yunus A. Çengel and Michael A. Boles48Sublimation is the process of passing from the solid phase directly into the vapor phase.
Sublimation line separates the solid and vapor regions on the phase diagram.
Subsonic flow occurs when a flow has a Mach number M < 1.
Superheated vapor is a vapor that is not about to condense (not a saturated vapor). A
superheated vapor has a temperature greater than the saturation temperature for the
pressure.
Superheated vapor region is all the superheated states located to the right of the
saturated vapor line and above the critical temperature line.
Supersaturated steam is steam that exists in the wet region without containing any
liquid. This phenomenon would exist due to the supersaturation process.
Supersaturation is the phenomenon owing to steam flowing through a nozzle with the
high velocities and exiting the nozzle in the saturated region. Since the residence time of
the steam in the nozzle is small, and there may not be sufficient time for the necessary
heat transfer and the formation of liquid droplets, the condensation of the steam may be
delayed for a little while.
Supersonic flow occurs when a flow has a Mach number M > 1.
Surface tension is the force per unit length used to overcome the microscopic forces
between molecules at the liquid–air interfaces.
Surrounding is the mass or region outside the thermodynamic system.
Surroundings are everything outside the system boundaries.
Surroundings work is the work done by or against the surroundings during a process.
Swamp coolers (see evaporative coolers)
Tds relations relate the Tds product to other thermodynamic properties. The first Gibbs
relation is Tds = du + Pdv. The second Gibbs relation is Tds = dh – vdP.
Theoretical air (see stoichiometric air)
Theoretical combustion (see stoichiometric combustion)