![]() ![]() The specific enthalpy of saturated liquid water (x=0) and dry steam (x=1) can be picked from steam tables. The exhausted steam is at a pressure well below atmospheric, and is in a partially condensed state (point F), typically of a quality near 90%. The reheater heats the steam (point D) and then the steam is directed to the low-pressure stage of steam turbine, where expands (point E to F). The steam must be reheated in order to avoid damages that could be caused to blades of steam turbine by low quality steam. In these turbines the high-pressure stage receives steam (this steam is nearly saturated steam – x = 0.995 – point C at the figure) from a steam generator and exhaust it to moisture separator-reheater (point D). Typically most of nuclear power plants operates multi-stage condensing steam turbines. Rankine Cycle – Thermodynamics as Energy Conversion Science ![]() Saturated liquid water, which has no latent heat and therefore 0% quality, will therefore only contain sensible heat. In the case of dry steam (100% quality), it contains 100% of the latent heat available at that pressure. At constant pressure, an addition of energy does not changes the temperature of the mixture, but the vapor quality and specific volume changes. Between these two states, we talk about vapor-liquid mixture or wet steam (two-phase mixture). On the other hand, when the vapor quality is equal to 1, it is referred to as the saturated vapor state or dry steam (single-phase). When the vapor quality is equal to 0, it is referred to as the saturated liquid state (single-phase). Wet steam is characterized by the vapor quality, which ranges from zero to unity – open interval (0,1). Subcooling margin is very important safety parameter of PWRs, since the boiling in the reactor core must be excluded. Analogically the subcooling is defined also in nuclear engineering but for another purpose.įor example, the temperature in the pressurizer can be maintained at 350 ☌ (662 ☏), which gives a subcooling margin (the difference between the pressurizer temperature and the highest temperature in the reactor core) of 30 ☌. For example, water normally boils at 100☌ (at atmospheric pressure) at room temperature 20☌ the water is termed “subcooled”. The term subcooling refers to a liquid existing at a temperature below its normal boiling point. If the temperature of the liquid is lower than the saturation temperature for the existing pressure, it is called either a subcooled liquid or a compressed liquid. If a water exists as a liquid at the saturation temperature and pressure with quality of x = 0, it is called a saturated liquid state (single-phase).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |