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HEAT PIPE
This document provides an overview of heat pipes, including their working principle, key components, types, advantages, and applications. A heat pipe transfers heat using an evaporation-condensation cycle within a sealed container consisting of a working fluid and capillary wick. Heat is absorbed at the evaporator section where the fluid evaporates, transferring heat through the vapor to the condenser section where it condenses, releasing heat and returning via the wick to the evaporator. Heat pipes can transfer heat very efficiently over long distances with minimal temperature difference due to the phase change process. Common applications include electronics cooling, aerospace systems, and industrial heat exchangers.
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HEAT PIPE
- 1. Presented by: ASHISH MISHRA R.N.-1474540007 SRMSCET,BAREILLY
- 2. Content Introduction Working Principle Components ofHeat Pipe Type of Heat Pipe Advantage of Heat Pipe Application
- 3. A heat pipeheat exchanger is a simple device which is made use of to transfer heat from one location to another, using an evaporation-condensation cycle. Heat pipes are referred to as the superconductors of heat due to their fast transfer capability with low heat loss. What is a Heat Pipe?
- 4. Working Principle • Theheat input region of the heat pipe is called evaporator. • The cooling region is called condenser. • In between the evaporator and condenser regions, there may be an adiabatic region.
- 5.
- 6. • Container • Workingfluid • Wick or Capillary structure
- 7. 1.Container The function ofthe container is to isolate the working fluid from the outside environment. Selection of the container material depends on many factors. These are as follows: Compatibility (both with working fluid and external environment) Strength to weight ratio Thermal conductivity Ease of fabrication, including welding, machinability and ductility Porosity Wettability
- 8. The prime requirementsare: 1. compatibility with wick and wall material 2. Good thermal stability 3. wettability of wick and wall materials 4. vapor pressure not too high or low over the operating temperature range. 5. high latent heat 6. high thermal conductivity 7. low liquid and vapor viscosities 8. high surface tension 9. acceptable freezing or pour point
- 9. 1. It isa porous structure made of materials like steel,alumunium, nickel or copper in various ranges of pore sizes. 2. The prime purpose of the wick is to generate capillary pressure to transport the working fluid from the condenser to the evaporator. 3. It must also be able to distribute the liquid around the evaporator section to any area where heat is likely to be received by the heat pipe.
- 10. 4. The maximumcapillary head generated by a wick increases with decrease in pore size. 5. The wick permeability increases with increasing pore size 6. Other necessary properties of the wick are compatibility with the working fluid and wettability.
- 12. Wick Design Two maintypes of wicks: homogeneous and composite. 1.Homogeneous- It made from one type of material or machining technique. Tend to have either high capillary pressure and low permeability or the other way around. 2.Composite- It made of a combination of several types or porosities of materials and/or configurations. Capillary pumping and axial fluid transport are handled independently.
- 14. Types of HeatPipes Thermo syphon Leading edge Rotating and revolving Cryogenic pumped loop heat pipe Flat Plate Micro heat pipes Variable conductance Capillary pumped loop heat pipe
- 15. Advantages May reduce oreliminate the need fir reheat, Allow cost effective manner to accommodate new ventilation standards, Requires no mechanical or electrical input, Are virtually maintenance free, Provide lower operating costs, Last a very long time, Are environmentally safe.
- 16. Applications Electronics cooling- smallhigh performance components cause high heat fluxes and high heat dissipation demands. Used to cool transistors and high density semiconductors. Aerospace- cool satellite solar array, as well as shuttle leading edge during reentry. Heat exchangers- power industries use heat pipe heat exchangers as air heaters on boilers. Other applications- production tools, medicine and human body temperature control, engines and automotive industry.
- 17. Applications Laptop heat pipesolution
- 18.
- 19. Camera Cooler Combined Heatpipe / water cooling Jacket for hi-def CCD camera.
- 20.
Editor's Notes
- #16 Lift and Drag Drag-based wind turbine In drag-based wind turbines, the force of the wind pushes against a surface, like an open sail. In fact, the earliest wind turbines, dating back to ancient Persia, used this approach. The Savonius rotor is a simple drag-based windmill that you can make at home (Figure 1). It works because the drag of the open, or concave, face of the cylinder is greater than the drag on the closed or convex section. Lift-based Wind Turbines More energy can be extracted from wind using lift rather than drag, but this requires specially shaped airfoil surfaces, like those used on airplane wings (Figure 2). The airfoil shape is designed to create a differential pressure between the upper and lower surfaces, leading to a net force in the direction perpendicular to the wind direction. Rotors of this type must be carefully oriented (the orientation is referred to as the rotor pitch), to maintain their ability to harness the power of the wind as wind speed changes. Airflow over any surface creates two types of aerodynamic forces— drag forces, in the direction of the airflow, and lift forces, perpendicular to the airflow. Either or both of these can be used to generate the forces needed to rotate the blades of a wind turbine.