What is double pipe heat exchanger?
A double pipe exchanger consists of one or more pipes or tubes inside a pipe shell. Basically two straight pipe lengths are connected at one end to form a U or “hair-pin.” Longitudinal fins may be used on the outside of the inner tube.
How is heat exchanger design calculated?
4.0 – HEAT EXCHANGERS CALCULATIONS:
- 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.
- T1 = Inlet tube side fluid temperature; t2 = Outlet shell side fluid temperature;
- ln (T1 – t2) (T2 – t1)
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 do you calculate pressure drop in a double pipe heat exchanger?
Total volumetric flow = 50000 kg/hr ÷ 988.0 kg/m3 = 50.61 m3/hr Volumetric flow in each 1″ tube = 50.61 ÷ 25 = 2.02 m3/hr Pressure loss per unit length of the tube is then calculated using EnggCyclopedia’s pressure drop calculators for pipes and tubes.
What is the difference between double pipe and shell and tube heat exchanger?
Double pipe heat exchanger consists of two concentric pipes of different diameters. One pipe is for hot fluid and another is for cold fluid. Shell and tube heat exchanger consists of a shell in which large number of parallel tubes are present. One fluid hot or cold flow in shell and other hot or cold flow in the tubes.
How does a double pipe heat exchanger works?
The double pipe heat exchanger works via conduction, where the heat from one flow is transferred through the inner pipe wall, which is made of a conductive material such as steel or aluminum. The double pipe heat exchanger is often used in counterflow, where its fluids move in opposite directions (as shown above).
Which is the component of double pipe heat exchanger?
The friction factor and the heat transfer coefficient are the major parameters to be considered in the design of double-pipe heat exchangers. Furthermore, they have four key design components: shell nozzles, tube nozzles, shell-to-tube closure, and return-bend housing [24].
How do you calculate the heat load of a heat exchanger?
The heat load of a heat exchanger can be derived from the following two formulas:
- Heat load, Theta and LMTD calculation. Where: P = heat load (btu/h)
- Heat transfer coefficient and design margin. The total overall heat transfer coefficient k is defined as:
How is Nusselt number calculated?
Formula
- 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 do you call a double pipe heat exchanger?
The double pipe heat exchanger is one of the simplest types of heat exchanger s. It is called double pipe heat surrounds the first. This is concentric tube construction. Flow in a double -pipe heat exchan ger can be co-current or countercurrent.
How is the duty of a heat exchanger determined?
The heat exchange duty a llows calculation of the log mean temperature difference and that together with the estimated overall heat transfer coefficient allows calculation of the required heat transfer surface area. Then pipe sizes, pipe lengths and number of bends can be determin ed.
What makes a counter current heat exchanger better?
The counter current mode enhances more area for heat transfer. Operations are enhanced by auxiliary equipments such as valves, pumps, meters, switches and controllers. Operations are carried out in accordance with operational procedures taking into consideration safety regulations.
