Evaluation the enthalpy of steam - thermodynamics, Mechanical Engineering

Evaluation the Enthalpy of Steam:

Let

hf = Heat of liquid or sensible heat of water in KJ/kg

hfg = Latent heat of vaporization of steam in KJ/kg

ts = Saturation in 0ºC corresponding to given pressure.

tsup  = Temperature of superheated steam in ºC

x     = dryness fraction of wet saturated steam

Cp   = Specific Heat of superheated steam at constant pressure in KJ/kg.k.

 

408_Evaluation the Enthalpy of Steam.png

(a) Enthalpy of dry saturated steam

1 kg of water will be raised first for saturation of temperature (ts) for which hf (sensible heat of water) quantity of heat will be needed. Then 1 kg of water at saturation temperature will be transformed into 1 kg of dry saturated steam for which hfg (latent heat of steam) will be required. Thus enthalpy of dry saturated steam can be given by

Hdry  (or hg)= hf  + hfg  kJ/kg

(b) Enthalpy of wet saturated steam

1 kg of water will be raised first to the saturation temperature (ts) for which hf (sensible heat of water) will be needed. Then 'x' kg of water at saturation temperature will be transformed into 'x' kg of dry saturated steam at same temperature for which x.hfg amount of heat will be required. Thus enthalpy of wet saturated steam can be given by

Hwet = hf  + x.hfg kJ/kg

(c) Enthalpy of superheated steam

1 kg of water will be raised first to saturation temperature (ts) for which hf (sensible heat of water) will be needed. Then, 1kg of water at saturation temperature will be transformed into 1kg dry saturated steam at same temperature for which hfg (latent heat of steam) will be needed. Finally, 1kg dry saturated steam will be transformed into 1kg superheated steam at same pressure for which heat needed is

1 × Cp(tsup - ts) = Cp (tsup  - ts) kJ

Thus enthalpy of superheated steam can be given by

       Hsup = hf  + hfg  + Cp  (tsup  - ts) kJ/kg

 

Posted Date: 10/15/2012 6:16:31 AM | Location : United States







Related Discussions:- Evaluation the enthalpy of steam - thermodynamics, Assignment Help, Ask Question on Evaluation the enthalpy of steam - thermodynamics, Get Answer, Expert's Help, Evaluation the enthalpy of steam - thermodynamics Discussions

Write discussion on Evaluation the enthalpy of steam - thermodynamics
Your posts are moderated
Related Questions
Forecasting: Forecasts play a vital role in determining material needs that constitute inventories and in establishing production plans. In this unit, you have studied the imp

ismb 600 load capacity length in 8 meter

Disadvantages of two stroke engine: The following are some of the disadvantages of two stroke engine when compared with four stroke engine: 1. As firing takes place in ever

For a theoretical OTTO cycle operating on compression ratio of 8.5:1taking in air at 15C and 101.3kPa and having a maximum cycle temp of 1800C.Calculate the temp after compression,

By introducing their model of neural excitability in 1952, Alan Lloyd Hodgkin and Andrew Huxley not only shed light on the mechanism underlying a very important phenomenon in Physi

Tank Drainage A large open vertical tank has three small, smooth, well-rounded orifices spaced equidistantly at ¼ h , ½ h , ¾ h up from the bottom of the tank (Fig. Q1). Water

Find out the horizontal and vertical components of the force: A force of 120 N is exerted on a hook in the ceiling as illustrated in Figure. Find out the horizontal and vertic

Natur e of Bending Stress If the beam is not loaded, it will not bend as shown in the figure-a. But if the beam is loaded, it will bend as shown in the figure-b, whatever may

Determine the Excavation of soil Excavation of soil in open well foundations is done  by dredging with grab buckets or similar equipment. The volume of excavated soil always e

Reaction Bonding Such bonding is attained by arranging for two or more components of a compacted body to respond to form both a desired phase and a bond among particles. The r