What is the purpose of baffles in heat exchanger and how the no of baffles are calculated?
The main roles of a baffle in a shell and tube heat exchanger are to: Hold tubes in position (preventing sagging), both in production and operation. Prevent the effects of steam starvation, which is increased with both fluid velocity and the length of the exchanger. Direct shell-side fluid flow along tube field.
Why are baffles used in a shell and tubes heat exchanger?
Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer …
Do heat exchangers need insulation?
Insulation on heat exchangers typically is not required to improve thermal efficiency because the exposed surface area of the plates is minimal in comparison to the total effective heat transfer area.
What is the main purpose of putting baffles in the shell side?
Baffles serve two important functions. First, they support the tubes during assembly and operation and help prevent vibration from flow-induced eddies. Second, they direct the shell-side fluid back and forth across the tube bundle to provide effective velocity and heat transfer rates.
Why gaps must be left between baffles and shells and between tubes and baffles?
While the leakage streams that flow through the gaps between the tubes and the holes in the baffles contribute to heat transfer, the leakage streams that flow through the gaps between the shell and the baffles do not participate in heat transfer; therefore the gap area {A_{\rm{GSB}}} should be kept as small as possible …
What is the role of the baffles in a shell and tube heat exchanger How does the presence of baffles affect the heat transfer and the pumping power requirements explain?
Baffles are panels that are placed in the shell and tube heat exchanger. The reason for placing baffles is to increase the heat transfer coefficient between the fluids. Baffles provide higher turbulence in the flow of fluid and thus the heat transfer coefficient increases.
Do baffles increase turbulence?
Baffles have also the purpose of increasing turbulence levels and, thus, heat exchange ratios (Nusselt number – Nu).
Why are baffles walls provided?
Why are the baffle walls provided? Explanation: The sedimentation tanks preferred are rectangular and are used widely. The flow takes place in horizontal direction that is length wise in rectangular tanks. Sometimes baffle walls are provided for rectangular tank to prevent short circuiting.
How many baffles does a heat exchanger have?
Solution
| *SHELL AND TUBE HEAT EXCHANGER RATING* | ||
|---|---|---|
| TUBE SIDE | SHELL SIDE | |
| NUMBER OF TUBES: | 270. | |
| NUMBER OF PASSES: | 6. | 3. |
| NUMBER OF BAFFLES: | 38. |
What will a larger baffle pitch contribute?
Nevertheless, the baffle spacing is the main design parameter for controlling shell-side pressure drop. Increasing the tube pitch also increases the flow area through the tube bundle and thereby lowers the pressure drop.
What are the four important parts of shell and tube heat exchanger?
The principal components of shell-and-tube heat exchangers are:
- Tubes.
- Tubesheet.
- Shell and Shell-Side Nozzles.
- Tube-Side Channel and Nozzles.
- Baffles.
- Tie-rods.
What is a shell and tube heat exchanger?
Shell and tube heat exchangers are, simply put, a device that puts two working fluids in thermal contact using tubes housed within an outer cylindrical shell. These two integral pathways are usually built out of thermally conductive metals that allow easy heat transfer ( steel , aluminum alloys , etc.).
What is a baffle in a shell and tube heat exchanger?
Baffles are installed in the shell of the shell and tube heat exchanger to create more turbulence and increase the flow time so that better heat exchange is possible. Baffles support the tubes so that damage and vibration of tubes are minimized.
What are the types of heat exchangers used in process piping?
There are various types of heat exchangers used in process piping. Shell and tube heat exchanger is the most widely used heat exchanger and are among the most effective means of heat exchange.
What are the saddles on a heat exchanger?
The heat exchanger is supported by saddles in the shell part. Tube bundles are removed during maintenance. Standard practice is to flow the corrosive fluid inside the tubes so that if corroded they can be easily replaced or repaired. Fig. 3 below shows a typical tube bundle.