Engineering

How to Calculate and Solve for Entropy of Wet Steam | Enthalpy

Last Updated on June 28, 2022

The entropy of wet steam is illustrated by the image below.

To compute for entropy of wet steam, three essential parameters are needed and these parameters are Entropy of Water (Sf), Enthalpy of Vapourisation (hfg) and Saturated Temprature (Ts).

The formula for calculating entropy of wet steam:

Sg = Sf + hfg / Ts

Where:

Sg = Entropy of Wet Steam
Sf = Entropy of Water
hfg = Enthalpy of Vapourisation
Ts = Saturated Temprature

Given an example;
Find the entropy of wet steam when the entropy of water is 12, the enthalpy of vapourisation is 10 and the saturated temperature is 14.

This implies that;

Sf = Entropy of Water = 12
hfg = Enthalpy of Vapourisation = 10
Ts = Saturated Temprature = 14

Sg = Sf + hfg / Ts
Sg = 12 + 10 / 14
Sg = 12 + 0.714
Sg = 12.71

Therefore, the entropy of wet steam is 12.71 J/K.

Calculating the Entropy of Water when the Entropy of Wet Steam, the Entropy of Vapourization and the Saturated Temperature is Given.

Sf = (Sg x Ts) – hfg

Where:

Sf = Entropy of Water
Sg = Entropy of Wet Steam
hfg = Enthalpy of Vapourisation
Ts = Saturated Temprature

Let’s solve an example;
Find the entropy of water when the entropy of wet steam is 10, the enthalpy of vapourization is 5 and the saturated temperature is 2.

This implies that;

Sg = Entropy of Wet Steam = 10
hfg = Enthalpy of Vapourisation = 5
Ts = Saturated Temprature = 2

Sf = (Sg x Ts) – hfg
Sf = (10 x 2) – 5
Sf = 20 – 5
Sf = 15

Therefore, the entropy of water is 15.

Calculating the Enthalpy of Vapourization when the Entropy of Wet Steam, the Entropy of Water and the Saturated Temperature is Given.

hfg = (Sg x Ts) – Sf

Where:

hfg = Enthalpy of Vapourisation
Sg = Entropy of Wet Steam
Sf = Entropy of Water
Ts = Saturated Temprature

Let’s solve an example;
Find the enthalpy of vapourization when the entropy of wet steam is 12, the entropy of water is 4 and the saturated temperature is 2.

This implies that;

Sg = Entropy of Wet Steam = 12
Sf = Entropy of Water = 4
Ts = Saturated Temprature = 2

hfg = (Sg x Ts) – Sf
hfg = (12 x 2) – 4
hfg = 24 – 4
hfg = 20

Therefore, the enthalpy of vapourization is 20.

Calculating the Saturated Temperature when the Entropy of Wet Steam, the Enthalpy of Vapourization and the Entropy of Water is Given.

Ts = Sf + hfg / Sg

Where:

Ts = Saturated Temprature
Sg = Entropy of Wet Steam
Sf = Entropy of Water
hfg = Enthalpy of Vapourisation

Let’s solve an example;
Find the saturated temperature when the entropy of wet steam is 20, the enthalpy of vapourization is 12 and the entropy of water is 4.

This implies that;

Sg = Entropy of Wet Steam = 20
Sf = Entropy of Water = 4
hfg = Enthalpy of Vapourisation = 12

Ts = Sf + hfg / Sg
Ts = 4 + 12 / 20
Ts = 16 / 20
Ts = 0.8

Therefore, the saturated temperature is 0.8.

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the entropy of wet steam.

To get the answer and workings of the entropy of wet steam using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

Web – https://www.nickzom.org/calculator-plus

To get access to the professional version via web, you need to register and subscribe to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Materials and Metallurgical under Engineering.

Now, Click on Chemical Reaction Thermodynamics under Materials and Metallurgical

Now, Click on Enthalpy under Chemical Reaction Thermodynamics

Now, Click on Entropy of Wet Steam under Enthalpy

The screenshot below displays the page or activity to enter your values, to get the answer for the entropy of wet steam according to the respective parameter which is the Entropy of Water (Sf), Enthalpy of Vapourisation (hfg) and Saturated Temprature (Ts).

Now, enter the values appropriately and accordingly for the parameters as required by the Entropy of Water (Sf) is 12, Enthalpy of Vapourisation (hfgis 10 and Saturated Temprature (Ts) is 14.

Finally, Click on Calculate

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the entropy of wet steam and presents the formula, workings and steps too.

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