How do you determine the number of tubes on a heat exchanger?

How do you determine the number of tubes on a heat exchanger?

4.0 – HEAT EXCHANGERS CALCULATIONS:

1. The main basic Heat Exchanger equation is: Q = U x A x ΔTm =
2. The log mean temperature difference ΔTm is: ΔTm =
3. (T1 – t2) – (T2 – t1) = °F.
4. T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;
5. ln (T1 – t2) (T2 – t1)

How many tubes are in a heat exchanger?

The tubes assembly is called “tube bundle”. Dear Nishtha, In Power plant 500-1000 MW or more turbine hot well surface condenser are available more than 10,000 Number of tubes. waste heat boiler in power plant gas turbine are shell & tube type heat exchanger are also larger size and having 5000-12000 number of tubes.

Why a large number of tubes is used in heat exchangers?

In order to transfer heat efficiently, a large heat transfer area should be used, leading to the use of many tubes. In this way, waste heat can be put to use. This is an efficient way to conserve energy.

What are the factors considering in design of a heat exchanger?

Thermal design of a shell and tube heat exchanger typically includes the determination of heat transfer area, number of tubes, tube length and diameter, tube layout, number of shell and tube passes, type of heat exchanger (fixed tube sheet, removable tube bundle etc), tube pitch, number of baffles, its type and size.

How do you calculate the overall heat transfer coefficient of a heat exchanger?

Composition

1. = the overall heat transfer coefficient (W/(m2•K))
2. = the contact area for each fluid side (m2) (with and expressing either surface)
3. = the thermal conductivity of the material (W/(m·K))
4. = the individual convection heat transfer coefficient for each fluid (W/(m2•K))
5. = the wall thickness (m).

What is baffle pitch?

The spacing between segmental baffles is called the baffle pitch. The baffle pitch and the baffle cut determine the cross flow velocity and hence the rate of heat transfer and the pressure drop. When the shell side heat transfer is sensible heating or cooling with no phase change, the baffle cut should be horizontal.

How do you design a heat exchanger?

For the sizing problem:

1. Calculate the effectiveness.
2. Calculate the capacity rate ratio.
3. Calculate the overall heat transfer coefficient.
4. Determine NTU.
5. Calculate the heat transfer surface area.
6. Calculate the length of the tube or heat exchanger.

What are the factors that can affect the efficiency of a heat exchanger?

The main factors affecting the performance heat exchanger tubes include: fluid velocity, tube diameter, converter tube shape (U or cross shape), converter layout order (horizontal or vertical), and Venting valve, material of tube sheet and channel and location order of input channel.

How do you calculate overall heat transfer?

How to calculate shell and tube heat exchanger?

Where, we get the A Overall (overall heat transfer area required) from the heat transfer rate equation (Equation-1). This equation is quite straight forward based on the geometry of the selected shell and tube heat exchanger.

Why are larger tubes used in heat exchanger?

Longer tube reduces shell diameter at the expense of higher shell pressure drop. Tubes of larger diameter are sometimes used either to facilitate mechanical cleaning or to achieve lower pressure drop. A maximum number of tubes in the shell increase turbulence, which increases the heat transfer rate.

What to look for in a heat exchanger material?

With so many factors to consider in choosing a material for your shell and tube heat exchanger, you may have a lot of questions. To start, you’ll need to decide which criteria are most critical to your operation. Criteria like thermal efficiency, cost, availability, corrosion resistance, cleanability and durability.

Can a shell and tube exchanger have multiple passes?

Multiple Passes Shell-and-tube heat exchangers can have multiple passes, such as 1-1, 1-2, 1-4, 1-6, and 1-8 exchangers, where the first number denotes the number of the shells and the second number denotes the number of passes. An odd number of tube passes is seldom used except the 1-1 exchanger.