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.
How many tubes does a heat exchanger have?
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.
How do you calculate shell diameter of a shell and tube heat exchanger?
The equivalent diameter is calculated along (instead of across) the long axes of the shell and therefore is taken as
four times the net flow area as layout on the tube sheet
(for any pitch layout) divided by the wetted perimeter.
What is 2/4 shell and tube exchanger?
Most shell-and-tube heat exchangers are either 1, 2, or 4 pass designs on the tube side. This refers to
the number of times the fluid in the tubes passes through the fluid in the shell
. … Two and four pass designs are common because the fluid can enter and exit on the same side.
How do you calculate heat exchanger?
- Free Convection Gas – Free Convection Gas : U = 1 – 2 W/m
2
K (typical window, room to outside air through glass) - Free Convection Gas – Forced liquid (flowing) water : U = 5 – 15 W/m
2
K (typical radiator central heating)
How many types of shell and tube heat exchanger are there?
The
three
flow types of shell and tube heat exchangers are parallel, counter, and cross. The design, operation, and applications necessitate the three flow types be used in combinations. Parallel flow is when the shell and tube sides enter the heat exchanger at the same end and flow directly to the opposite end.
How do you calculate tube pitch in heat exchanger?
TEMA standards recommends a minimum tube pitch of
1.25 * Tube outer diameter for triangular pitch
. For example, if we have a tube outer diameter of 12.7 mm (0.5 inch) then the recommended tube pitch for triangular pitch arrangement is: 1.25 * 12.7 mm = 16 mm (0.6 inch).
What is the formula for number of tubes?
Solution: The surface area per tube will be:
Sa = πDL = π (3/12)
(10) ft2 = 7.854 ft2 – (D – tube diameter in ft). The number of tubes required would thus be: n = 178.7 ft2 = 22.7 tubes (23 or 24 tubes).
How do you calculate the overall heat transfer coefficient for shell and tube heat exchanger?
The convective heat transfer coefficient of the shell and tube heat exchanger is calculated based on the following correlation:
(4) U = Q A × L M T D
where, A is total heat transfer area, m
2
, Q is heat transfer from hot stream into cold stream, W, LMTD is logarithmic mean temperature difference, K.
How do you calculate tube bundle diameter?
An easy way to measure the diameter is
to take the circumference of the shell, then divide by 3.14 to
give you the diameter of the bundle. Overall Length (OAL) is the length measured from the face of the tubesheet through the entire length of the tubes.
What can we infer from the name 1/4 shell and tube heat exchanger?
1. Shell and Tube Heat Exchangers are
not commonly used in industries because of their inability to handle high pressure and temperature
. … Hence we can easily infer from this that it is a 2-4 shell and tube HE.
How does shell and tube heat exchanger work?
A shell and tube exchanger consists of a number of tubes mounted inside a cylindrical shell. …
Two fluids can exchange heat
, one fluid flows over the outside of the tubes while the second fluid flows through the tubes. The fluids can be single or two phase and can flow in a parallel or a cross/counter flow arrangement.
What is tube in tube heat exchanger?
The equipment consists of a
single tube mounted inside an outer shell tube
, so that the product medium flows counter-current through the inner tube, with the service medium around it. … The unit features a fully welded construction with a bellow-on-shell tube to absorb thermal expansion.
How is Nusselt number calculated?
- Nusselt Number : Nu = hL/k.
- Convection Heat Transfer Coefficient : k = Nuk/L.
- Characteristic Length : L = Nuk/h.
- Thermal Conductivity of the Fluid : k = hL/Nu.
- Where, Nu = Nusselt Number, h = Convection Heat Transfer Coefficient, L = Characteristic Length, k = Thermal Conductivity of the Fluid.
What is Nusselt number formula?
the Nusselt number, which is
Nu
Dh
= 890
. the hydraulic diameter of the fuel channel is: D
h
= 13,85 mm. the thermal conductivity of reactor coolant (300°C) is: k
H2O
= 0.545 W/m.K. the bulk temperature of reactor coolant at this axial coordinate is: T
bulk
= 296°C. the linear heat rate of the fuel is: q
L
= 300 W/cm (F
Q
≈ …
What is correct formula of Biot number?
The Biot number equals
the product of the heat transfer coefficient and the characteristic length divided by thermal conductivity
.
How many types of heat exchangers are there?
There are
two
main types of regenerative heat exchangers—static heat exchangers and dynamic heat exchangers.
How do you calculate Reynolds number in heat exchanger?
Reynolds number:
Re = ρUL/μ ≡ UL/ν (forced convection)
. A measure of the balance between the inertial forces and the viscous forces. Nusselt number: Nu = hL/kf This can be considered as the dimensionless heat transfer coefficient.
How are tubes attached to tube sheet?
Tube Sheets
Tubes are attached to the tube sheet by
pneumatic or hydraulic pressure, or by roller expansion
. … Low carbon steel tube sheets can include a layer of a higher alloy metal bonded to the surface to provide more effective corrosion resistance without the expense of using the solid alloy.
What is pitch in shell and tube heat exchanger?
The distance between the centers of the tube hole is called the tube pitch; normally the tube pitch is
1.25 times the outside diameter of the tubes
. Other tube pitches are frequently used to reduce the shell side pressure drop and to control the velocity of the shell side fluid as it flows across the tube bundle.
How do you calculate effective heat exchanger?
The effectiveness (ε) of a heat exchanger is defined as
the ratio of the actual heat transfer to the maximum possible heat transfer
. Qmax is the minimum of these two values i. e. aRajput, R.K., 2007,Engineering Thermodynamics, Laxmi Publications, New Delhi.
How do you create a shell and tube heat exchanger?
- Define the essential process requirements. …
- Select suitable type of heat exchanger. …
- Fix some of the design parameters to create a heat exchanger model. …
- Rating of the heat exchanger design. …
- Create specification sheet with finalized heat exchanger design.
How do you calculate overall heat transfer coefficient in heat exchanger?
The overall heat transfer coefficient
R = Resistance(s) to heat flow in pipe wall (K/W)
Other parameters are as above. The heat transfer coefficient is the heat transferred per unit area per kelvin. Thus area is included in the equation as it represents the area over which the transfer of heat takes place.
How do you calculate the overall heat transfer coefficient of a plate heat exchanger?
- Heat load, Theta and LMTD calculation. Where: P = heat load (btu/h) m = mass flow rate (lb/h) …
- Heat transfer coefficient and design margin. The total overall heat transfer coefficient k is defined as: α
1
= The heat transfer coefficient between the warm medium and the heat transfer surface (btu/ft
2
h °F)
How is shell side heat transfer coefficient calculated?
- D
s
, the shell inside diameter. - f
B
, the fraction of the shell cross-section that makes up the baffle window. - N
bt
, the number of tubes in the baffle window (usually approximated by f
b
*N
tubes
) - P
B
, the baffle pitch (spacing) - p
t
, the tube pitch. - d
o
, the tube outside diameter.
What is equivalent diameter in heat exchanger?
The equivalent diameter is given by
d
eq
= 4S/P
, where S is the cross section and P the perimeter of the flow, L is the path length and ξ is a friction factor expressed as a function of Reynolds number and device geometry. Heat transfer and pressure drop calculations are interrelated.
How many times do we have to calculate for Nusselt number in a double pipe heat exchanger?
How many times do we have to calculate for Nusselt number in a Double Pipe Heat Exchanger? Explanation: For a double pipe HE, we have to calculate Nusselt number
twice
, once for the inner pipe to calculate Convective Heat Transfer Coefficient for the inner pipe. Similarly, the second time for the annulus side. 5.
How is a plate type he better than a shell and tube he one of the following is not correct?
7. How is a Plate-type HE better than a Shell and tube HE, one of the following is not correct. Explanation: All the statements
are correct except that the thermal stress in higher in Plate type
, which in reality is higher in shell and tube owing to its lesser surface area compared to plat type HE.
What is the formula for the diameter of the single phase core type transformer?
5. The formula for single phase core type and three phase core type diameter and height are same. Explanation:
D = diameter of circumscribing circle + Width of window
is the diameter of single phase and 3 phase core type transformers.
What is Shell ID?
Prints the user id (gid)
and group id (gid) of the user that is running the command. Additionally, it also prints all groups that the user belongs to.
What is shell and tube evaporator?
The main function of Shell & Tube Type Evaporator is to
act as a heat exchanger in a vessel form
. This is mainly done to cool closed circuit for re-circulating fluid flow. … The refrigerants passed through the expansion device that passed into tubes and evaporates to produce a cooling effect.
How many passes does the tube side fluid make in this shell and tube heat exchanger?
Either the tube-side fluid, the shell-side fluid, or both may make more than one pass through the heat exchanger. On the tube side, multiple passes are achieved by means of U-tubes or by partitioning the headers. The number of tube-side passes is usually
one, two, four, or six, but may be as high as 16
.
What is the maximum baffle spacing for a shell and tube heat exchanger?
Sinnott (1993) concluded that effective baffle spacing range is
between 0.2 to 1 from shell diameter
[10].
What is Nusselt number ratio?
Nusselt number is
a measure of the ratio between heat transfer by convection (α) and heat transfer by conduction alone (λ/L)
. Convective heat transfer relationships are usually expressed in terms of Nusselt number as a function of Reynolds Number and Prandtl Number.
What is the difference between Biot number and Nusselt number?
Biot number uses thermal conductivity of the body
(not fluid), whereas Nusselt number uses thermal conductivity of the fluid. … Nusselt number can be used for heat exchangers, because fluid convection dominates, calculation of the heat transfer coefficient of various flows such as in pipes.
What does Nusselt number equal to 1 mean?
If the Nusselt number is about 1, it represents that
the heat transfer is conduction only
, but if the value is between 1 and 10, then it shows laminar of slug flow. If the range is more, it is active convection with turbulence in the 100–1000 range.
