Shell-and-tube heat exchanger

Definition

A shell-and-tube heat exchanger is a type of heat exchanger that consists of a series of tubes, one set containing the hot fluid and the other the cold fluid, arranged within a cylindrical shell. This design allows for efficient heat transfer between the fluids while providing structural integrity and ease of maintenance. The arrangement minimizes pressure drop and optimizes heat transfer surface area, making it widely used in various industrial applications.

5 Must Know Facts For Your Next Test

1. Shell-and-tube heat exchangers can be configured in different arrangements, including parallel flow, counterflow, and crossflow, each affecting efficiency and application suitability.
2. They are designed to handle high pressures and temperatures, making them ideal for industries like oil refining and power generation.
3. The tube materials can vary, with options such as stainless steel or titanium chosen based on corrosion resistance and thermal performance requirements.
4. Maintenance is facilitated by the ability to clean and replace individual tubes without having to replace the entire unit.
5. The overall heat transfer coefficient for shell-and-tube heat exchangers depends on factors like fluid velocities, temperature differences, and fouling on the tube surfaces.

Review Questions

• How does the design of a shell-and-tube heat exchanger enhance its efficiency compared to other types of heat exchangers?
  • The design of a shell-and-tube heat exchanger enhances its efficiency primarily through its large surface area for heat exchange and its ability to facilitate turbulent flow. This turbulence increases the convective heat transfer coefficients on both sides of the tubes, leading to more effective heat transfer. Additionally, the arrangement allows for different flow configurations like counterflow, which significantly improves the temperature gradient between the fluids, further enhancing overall efficiency.
• Discuss how factors such as fluid velocity and fouling affect the performance of shell-and-tube heat exchangers.
  • Fluid velocity is crucial in shell-and-tube heat exchangers because higher velocities can enhance turbulence, improving the rate of heat transfer. However, excessive velocity can lead to erosion or noise issues. Fouling refers to the accumulation of unwanted materials on the heat transfer surfaces, which reduces efficiency by acting as an insulating layer. Regular maintenance is essential to manage fouling and maintain optimal performance.
• Evaluate the role of material selection in shell-and-tube heat exchangers and its impact on operational longevity and efficiency.
  • Material selection plays a critical role in the longevity and efficiency of shell-and-tube heat exchangers. The choice of materials like stainless steel or titanium can significantly affect resistance to corrosion and erosion, especially in harsh environments or when dealing with aggressive fluids. Properly chosen materials help maintain structural integrity under high temperatures and pressures while minimizing maintenance costs over time. This decision also impacts thermal conductivity, which directly influences heat transfer efficiency.

Related terms

Heat transfer: The process by which thermal energy moves from a hotter object to a cooler one, typically through conduction, convection, or radiation.

Thermal conductivity: A measure of a material's ability to conduct heat, crucial for determining the efficiency of heat exchangers.

Counterflow: A flow arrangement in heat exchangers where the hot and cold fluids move in opposite directions, enhancing heat transfer efficiency.