How Can I Correctly Calculate Wall Temperature in an Air Cooled Steam Condenser?

In summary, the problem is related to finding the wall temperature in order to calculate the condensation heat transfer coefficient for an air cooled condenser. The necessary data includes the number of tubes, tube dimensions, number of fins, effective length of one tube, fin tip diameter, and material conductivity. The correct wall temperature is 197.5 C, and to calculate it, a combination of thermal resistances in parallel and series must be used. The Nusselt equation can then be used to calculate the condensation heat transfer coefficient.
  • #1
ank59
2
0
Hey my problem is related to air cooled condenser

The condenser is for removing 5MW thermal power from steam at 350 C, the pressure is 170 kg/cm2. The average temperature of outside air is 95 C(inlet at 45 C and outlet at 145 C).
the data is as follows:

no of tubes : 182
tube od =25.4 mm
tube id= 20.58mm
no of fins= 196.5 /m
effective length of one tube = 6.074m
fin tip diameter=57.15 mm
material conductivity = 26.57 W/mK

I want to calculate the wall temperature so that condensation heat transfer coefficient can be obtained by Nusselt equation but I am getting a wrong answer again and again, can anybody please help me in this problem. The correct answer is 197.5 C.

Generally the film resistance of steam is takes as negligible so can anybody comment on this, and is there any separate formula for finned tube to calculate the wall temperature.
 
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  • #2
To calculate the wall temperature, you need to use a combination of thermal resistances in parallel and series. The thermal resistances in series are the resistance due to conduction through the tube wall, the resistance due to conduction through the fin material, and the resistance due to convection between the outside surface of the fin and the air. The thermal resistances in parallel are the resistance due to conduction through the fin material and the resistance due to convection between the outside surface of the fin and the air. Combining all of these resistances together will give you the total thermal resistance from the steam side to the air side. You can then use the known values of the steam side temperature and the air side temperature to calculate the wall temperature using the equation: Wall temperature = (Steam side temperature + Air side temperature) / 2 Once you have the wall temperature, you can calculate the condensation heat transfer coefficient using the Nusselt equation.
 

FAQ: How Can I Correctly Calculate Wall Temperature in an Air Cooled Steam Condenser?

1. What is an air cooled steam condenser?

An air cooled steam condenser is a type of heat exchanger that is used to condense steam into liquid form by using air as the cooling medium. It is commonly used in power plants to convert the steam generated by the turbine back into water for reuse.

2. How does an air cooled steam condenser work?

An air cooled steam condenser uses a series of tubes and fins to transfer heat from the steam to the surrounding air. The steam enters the condenser at a high temperature and pressure, and as it passes through the tubes, it is cooled by the air. This causes the steam to condense into liquid form, which can then be collected and reused.

3. What are the advantages of using an air cooled steam condenser?

One of the main advantages of using an air cooled steam condenser is that it does not require a constant supply of water like other types of condensers. This makes it more environmentally friendly and cost-effective. It also has a smaller footprint, making it easier to install in smaller spaces.

4. What are the disadvantages of using an air cooled steam condenser?

One of the main disadvantages of using an air cooled steam condenser is that it is less efficient than other types of condensers, such as water cooled condensers. This is because air is not as effective at transferring heat as water. Additionally, air cooled steam condensers may require more maintenance and have a shorter lifespan due to the exposure to outdoor elements.

5. How is the performance of an air cooled steam condenser measured?

The performance of an air cooled steam condenser is typically measured by its efficiency, which is the percentage of heat from the steam that is transferred to the cooling medium. Other factors that may be measured include the amount of steam that is condensed and the temperature difference between the inlet and outlet of the condenser.

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