How do I calculate the heat transfer of a shell and tube heat exchanger?
The main basic Heat Exchanger equation is:
- Q = U x A x ΔTm = The log mean temperature difference ΔTm is:
- ΔTm = (T1 – t2) – (T2 – t1)
- = °F. Where:
- T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;
- ln (T1 – t2) (T2 – t1)
How is shell side heat transfer coefficient calculated?
Shell Side Heat Transfer Coefficients
- Ds, the shell inside diameter.
- fB, the fraction of the shell cross-section that makes up the baffle window.
- Nbt, the number of tubes in the baffle window (usually approximated by fb*Ntubes)
- PB, the baffle pitch (spacing)
- pt, the tube pitch.
- do, the tube outside diameter.
How efficient are shell and tube heat exchangers?
Plate heat exchangers are up to five times more efficient than shell-and-tube designs….Overall Heat Transfer Coefficient (U Value)
| Overall Heat Transfer Coefficient – U – | ||
|---|---|---|
| Shell and Tube | 150-1200 | 25-200 |
| Plate and Frame | 1000-4000 | 150-700 |
How do you calculate the heat transfer coefficient of a heat exchanger?
As the mass flow may be calculated with dm = dv x ρ (volume flow times density) we will get the “qualitative” Heat transfer coefficient αm . Using: T2, T1 the inlet and outlet temperature of the fluids and the volume flow. The heat loss is also taken as constant.
What is overall heat transfer coefficient?
The overall heat transfer coefficient, or U-value, refers to how well heat is conducted through over a series of resistant mediums. Its units are the W/(m2°C) [Btu/(hr-ft2°F)].
What is shell side heat transfer coefficient?
The shell side heat transfer coefficient is improved by providing baffles on the shell side and creating cross flow of shell side fluid with respect to the tube bundle. The commonly used baffle is the segmental baffle.
How will you increase the tube side heat transfer coefficient?
Segmental baffles are the most commonly used. They improve the heat transfer by enhancing fluid turbulence or local mixing on the shell side as a result of causing the shell side fluid to flow in a zigzag manner across the tube bundle. It also increases the pressure drop.
What is the most efficient heat exchanger design?
Plate exchanger is the most efficient due to turbulent flow on both sides. High heat-transfer coefficient and high turbulence due to even flow distribution are important.
Which heat exchanger is more efficient in heat transfer?
Each of the three types of heat exchangers (Parallel, Cross and Counter Flow) has advantages and disadvantages. But of the three, the counter flow heat exchanger design is the most efficient when comparing heat transfer rate per unit surface area.
What does a higher heat transfer coefficient mean?
The heat transfer coefficient expresses the amount of heat transferred between a fluid (either a liquid or gas) and a solid surface by convection. The larger the heat transfer coefficient, the more heat transfer occurs.
What is the heat transfer coefficient of aluminum?
3.14. 5 Thermal conductivity coefficient
| Metals | ||
|---|---|---|
| Aluminium | 239 | 0.16 |
| Antimony | 18 | 0.11 |
| Brass (60/40) | 96 | 0.18 |
| Cadmium | 92 |
How to calculate overall heat transfer coefficient for a shell exchanger?
We can use the following equation to get the overall heat transfer coefficient for a shell & tube exchanger. Note, this overall heat transfer coefficient is calculated based on the outer tube surface area (Ao). So it must be multiplied by the Ao value for using in the overall heat transfer equation.
How do you calculate the heat transfer coefficient of a tube?
h shell = h shellv = 0.0076* [λ 3 *ρ 2 *g/μ 2] 1/3 [ (4*Gv) / μ] 0.4 The heat transfer coefficient is the sum of the convection inside the tube, the conduction through the tubes, the convection outside the tube, also considering the fouling resistances on both sides of the tube.
How do you calculate the heat exchange coefficient of a condenser?
G = m / [ (Nt/nt).π.d i2 /4] The calculation of the heat exchange coefficient on the shell side depends on the orientation of the condenser, vertical or horizontal, and on the flow regime in the shell, laminar or turbulent. The Reynolds number is, for the liquid condensate, expressed as :
What is the optimum thermal design of a shell and tube exchanger?
The optimum thermal design of a shell and tube heat exchanger involves the consideration of many interacting design parameters which can be summarised as follows: Process 1. Process fluid assignments to shell side or tube side. 2. Selection of stream temperature specifications.