What is the characteristic of flow and heat transfer in natural circulation?
Best insight from top research papers
The characteristic of flow and heat transfer in natural circulation is influenced by various factors. The flow rate of the fluid is affected by the static head difference between the vertical tubes, and it becomes unstable below a certain value of the head difference . The heat transfer coefficient is mainly influenced by the power input, with different trends observed for different liquid metals . In parallel channel natural circulation loops, the steady-state mass flow rate and average Nusselt number are higher compared to single channel loops . The flow and heat transfer characteristics of parallel loops connected in the lower heated sections have been investigated, and the results have been compared with a correlation proposed by Vijaiyan . Natural circulation mass flow increases with heat flux and decreases with system pressure, and the heat transfer intensity of natural circulation is lower than that of forced circulation .
Answers from top 4 papers
More filters
| Papers (4) | Insight |
|---|---|
6 Citations | The paper states that natural circulation mass flow increases with increasing heat flux and decreasing system pressure. Natural circulation heat transfer is strongly affected by system pressure and heat flux. The heat transfer intensity of natural circulation is lower than that of forced circulation. |
30 Sep 2018 | The paper investigates the flow and heat transfer characteristics of parallel loops in single-phase natural circulation. |
2 Citations | The flow and heat transfer in natural circulation are mainly affected by power, with the heat transfer coefficient increasing with power. The flow rate and outlet temperature increase with power, while pressure has minimal effect on flow and outlet temperature. |
01 Jan 2019 1 Citations | The paper investigates the flow and heat transfer characteristics of natural circulation loops (NCLs) with parallel channels. It shows that the mass flow rate and average Nusselt number increase with power input, and the parallel channel NCL has a higher mass flow rate and average Nusselt number compared to the single channel NCL. |
Related Questions
What are the types of heat transfer? explain these?5 answersHeat transfer involves the rate of heat flow due to temperature differences. There are three main types of heat transfer: conduction, convection, and radiation. Conduction occurs in solids and is determined by the temperature gradient and thermal conductivity of the material. Convection is the dominant form of heat transfer in liquids and gases, and it involves the transfer of heat through the movement of the fluid. Radiation heat transfer occurs between solid surfaces separated by air gaps and is in the form of electromagnetic radiation. These types of heat transfer are relevant to various applications, including electrical machines. In the context of process heat transfer equipment, heat flow mechanisms can be categorized as conduction, convection, and radiation, which are often combined. The heat load on an exchanger is typically determined by the process service conditions, and fouling can be a major issue in heat exchanger operations. Forced convection, natural convection, boiling, condensation, or a combination of these are the types of convection heat transfer. Heat exchangers are used to transfer heat between fluids without physical contact, and the design of heat exchangers involves various methods and calculations, such as the logarithmic mean temperature difference method and the number of transfer units method.
How is heat transfer used in food processing?5 answersHeat transfer is an essential process in food processing, as it is involved in various operations such as heating, cooling, sterilization, and drying. Different heat transfer mechanisms, including conduction, convection, and radiation, are utilized in these processes. Conduction involves the transfer of heat from the most energetic molecules to neighboring molecules, and it plays a vital role in methods like sterilization and frying. Convection involves the transfer of heat through the movement of fluids, and it is used in heat exchangers to transfer heat between the food product and the heating or cooling fluid. Radiation is the transfer of heat energy via electromagnetic waves and is particularly efficient at high temperatures. It does not require direct contact between the heat source and the heated body. Understanding the thermal characteristics of food and the use of nanofluids as heat transfer fluids can enhance the overall efficiency of heat transfer in food processing. Computational fluid dynamics techniques, such as the lattice Boltzmann method, can also be used to analyze and simulate heat transfer in food treatment processes.
What is the meaning of natural climate change?3 answersNatural climate change refers to the changes in climate that occur due to natural processes and factors, such as variations in solar activity, volcanic eruptions, and variations in Earth's orbital parameters. These natural processes have historically caused climate to change and will continue to do so in the future. Human influences, such as greenhouse gas emissions, are unlikely to dominate these natural processes. It is important to understand and study natural climate change in order to implement policies for sustainable development and to mitigate the impacts of weather and climate extremes. The effects of natural climate change can be seen in the growth and breakup of continents, inorganic carbonate-silicate cycles, volcanic activity, glaciations, and biotic evolution. These natural processes and factors contribute to the overall variability and changes in Earth's climate system.
What is the relevance of heat transfer?5 answersHeat transfer is relevant in various fields such as energy systems, electrical machines, and process industries. It plays a key role in reducing greenhouse gas emissions by improving energy efficiency and reducing energy consumption. In electrical machines, heat transfer is important for dissipating heat in solid regions and determining the rate of heat transfer by convection. Heat transfer is also essential in the design of process heat transfer equipment in refining, gas processing, chemical, and petrochemical plants. Understanding heat transfer mechanisms, such as conduction, convection, and radiation, is crucial for efficient heat transfer design and operation. Additionally, heat transfer is relevant in the context of thermal energy exchange between systems and their surroundings, involving the exchange of kinetic energy through collisions or interactions. Overall, heat transfer is essential for energy efficiency, equipment design, and environmental sustainability.
What is the effect of natural convection on fluid transport?4 answersNatural convection in fluid environments is less efficient than forced convection due to the lack of fluid motion. It relies on the strength of the buoyancy effect and the fluid's viscosity. The effect of natural convection on fluid transport can be observed in various scenarios. For example, in the study of Prabhakar fractional Jeffrey fluid, the flow characteristics and physical parameters such as fractional parameters, Grashof number, Prandtl number, and Jeffrey parameters were found to affect the temperature and velocity of the convection flow. In the case of the Borexino detector, numerical analyses were used to understand the fluid dynamics and background behavior caused by natural convection. The results showed a good agreement between calculation and experimental data, demonstrating the applicability of the methodology. Similarly, in the study of Prabhakar-like fractional viscoelastic fluids, the generalized memory effects described by the time-fractional Prabhakar derivative were found to influence the velocity and heat transfer of the fluid.
What are the different types of heat transfer?2 answersHeat transfer is the exchange of energy between materials due to a temperature difference. There are three types of heat transfer: conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between materials. Convection is the transfer of heat through the movement of fluids, such as air or water. Radiation is the transfer of heat through electromagnetic waves. These three mechanisms can occur simultaneously in real-world situations, and solving heat transfer problems often involves considering the combined effects of conduction, convection, and radiation.