화학공학실험2 화공실2 Double-pipe heat exchanger 결과레포트

문서 내 토픽

1. Double-pipe heat exchanger

이 실험에서는 이중관 열교환기의 특성을 조사했습니다. 이중관 열교환기에서는 한 유체가 내부 작은 관 내부를 흐르고 다른 유체는 두 관 사이의 환상 공간을 흐릅니다. 전체 열전달 계수(U)는 단순 열전달 방정식을 기반으로 측정되었습니다.
2. Co-current flow

Co-current flow에서는 고온 유체와 저온 유체의 흐름 방향이 같아 최고 온도와 최저 온도가 서로 마주보고 있어 열교환이 시작됩니다. 온도 차이가 더 크기 때문에 열전달 계수가 더 큽니다.
3. Counter-current flow

Counter-current flow에서는 고온 유체와 저온 유체의 흐름 방향이 반대이므로 최고 온도와 최저 온도가 서로 반대편에 위치합니다. 온도 차이가 점점 감소하면서 열교환이 이루어지므로 열전달 계수가 더 작습니다.
4. Log mean temperature difference (LMTD)

LMTD는 Co-current flow에서 더 작고 Counter-current flow에서 더 큽니다. 이는 Co-current flow에서 입출구 온도 차이가 더 크기 때문입니다.
5. Overall heat transfer coefficient

전체 열전달 계수는 LMTD와 열전달량의 관계식을 통해 계산할 수 있습니다. Counter-current flow에서 더 큰 값을 가집니다.

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1. Double-pipe heat exchanger

A double-pipe heat exchanger is a type of heat exchanger that consists of two concentric pipes, with one fluid flowing through the inner pipe and another fluid flowing through the annular space between the inner and outer pipes. This design allows for efficient heat transfer between the two fluids, as the close proximity of the pipes and the counter-current flow pattern maximize the temperature difference between the fluids. Double-pipe heat exchangers are commonly used in a variety of industrial applications, such as heating and cooling systems, chemical processing, and power generation, due to their simplicity, reliability, and ease of maintenance. They are particularly well-suited for applications where the fluids have a large temperature difference or where the flow rates are relatively low. However, the limited surface area and the potential for fouling can be drawbacks of this design, and larger-scale applications may require more complex heat exchanger configurations.
2. Co-current flow

Co-current flow is a heat exchanger configuration where the two fluids flow in the same direction, with the hot fluid entering at one end and the cold fluid entering at the same end. In this arrangement, the temperature difference between the fluids decreases along the length of the heat exchanger, resulting in a lower overall heat transfer efficiency compared to counter-current flow. However, co-current flow can be advantageous in certain applications, such as when the fluids have a large temperature difference or when the heat exchanger needs to be compact and simple. Co-current flow is often used in shell-and-tube heat exchangers, where the shell-side fluid flows in the same direction as the tube-side fluid. While co-current flow is less efficient than counter-current flow, it can still be a viable option in situations where the overall system design or operational requirements make it the preferred choice.
3. Counter-current flow

Counter-current flow is a heat exchanger configuration where the two fluids flow in opposite directions. In this arrangement, the temperature difference between the fluids is maximized, resulting in a higher overall heat transfer efficiency compared to co-current flow. The hot fluid enters at one end of the heat exchanger, while the cold fluid enters at the opposite end. As the fluids flow through the heat exchanger, the temperature of the hot fluid decreases, and the temperature of the cold fluid increases, creating a constant temperature difference that drives the heat transfer process. Counter-current flow is the most efficient heat exchanger configuration and is widely used in a variety of industrial applications, such as power generation, chemical processing, and HVAC systems. The ability to achieve a higher temperature difference and better heat recovery makes counter-current flow the preferred choice in many heat exchanger designs.
4. Log mean temperature difference (LMTD)

The log mean temperature difference (LMTD) is a crucial parameter in the design and analysis of heat exchangers. It represents the average temperature difference between the hot and cold fluids in a heat exchanger, taking into account the non-linear temperature profiles of the fluids. The LMTD is calculated using the inlet and outlet temperatures of the hot and cold fluids, and it is used to determine the heat transfer rate and the required heat exchanger surface area. The LMTD is particularly important in counter-current flow heat exchangers, where the temperature difference between the fluids varies along the length of the heat exchanger. By using the LMTD, designers can accurately predict the heat transfer performance and ensure that the heat exchanger is sized appropriately for the given application. Understanding and correctly applying the LMTD concept is essential for the efficient design and optimization of heat exchangers in a wide range of industries.
5. Overall heat transfer coefficient

The overall heat transfer coefficient (U) is a crucial parameter in the design and analysis of heat exchangers. It represents the overall effectiveness of heat transfer between the hot and cold fluids in a heat exchanger, taking into account the individual heat transfer coefficients of the fluids, the thermal conductivity of the heat exchanger materials, and any fouling or resistance to heat transfer. The overall heat transfer coefficient is used to calculate the heat transfer rate and the required heat exchanger surface area, and it is influenced by factors such as fluid properties, flow rates, and heat exchanger geometry. Accurately determining the overall heat transfer coefficient is essential for the efficient design and optimization of heat exchangers, as it allows engineers to predict the heat transfer performance and ensure that the heat exchanger is sized appropriately for the given application. Understanding and properly applying the concept of the overall heat transfer coefficient is a fundamental aspect of heat exchanger design and analysis in various industries, including power generation, chemical processing, and HVAC systems.