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What is the physical significance of the Nusselt number please defined it?

What is the physical significance of the Nusselt number please defined it?

Nusselt number represents the ratio of heat flux by fluid when heat is transferred through fluid layer by convection when fluid involves some motion to heat flux by fluid when heat is transferred through fluid layer by conduction when fluid is motionless.

What will be the relation between conduction and convection heat transfer when the value of Nusselt number equals unity?

A Nusselt number of Nu=1 for a fluid layer represents heat transfer across the layer by pure conduction. The larger the Nusselt number, the more effective the convection. A larger Nusselt number corresponds to more effective convection, with turbulent flow typically in the 100–1000 range.

What does Nusselt number depend on?

The Nusselt number in the fully developed laminar flow is constant and depends on the channel geometry and the wall heat transfer boundary condition. For a rectangular channel, the Nusselt number depends on the channel aspect ratio αc=a/b and the wall boundary conditions.

What is heat transfer coefficient explain its physical significance?

The heat transfer coefficient is the heat transferred per unit area per kelvin. Thus area is included in the equation as it represents the area over which the transfer of heat takes place. The areas for each flow will be different as they represent the contact area for each fluid side.

What are the factors affecting heat transfer coefficient?

Heat transfer coefficient depends on both the thermal properties of a medium, the hydrodynamic characteristics of its flow, and the hydrodynamic and thermal boundary conditions.

What is heat generation give two examples?

Geothermal energy is a type of heat energy generated and stored beneath the surface of the Earth. This type of energy is used to heat homes and buildings. A huge amount of heat energy is stored in a bolt of lightning, which can strike and start a fire or cause an electrical outage.

What is heat generation explain with examples?

Heat generation is nothing but conversion of one form of energy(like electrical, chemical or nuclear energy) into thermal energy(heat energy) inside a solid. The temperature of the solid increases during this process. Example 1 : A system undergoing an exothermal reaction raises the temperature of the system.

What are the 5 sources of heat?

Here are only some of your many choices for heating energy sources: natural gas, propane (LP), oil, coal, wood, electricity, heat pumps, ground source heat pumps and solar energy.

What are the three main sources of heat on Earth?

Radioactive potassium, uranium and thorium are thought to be the three main sources of heat in the Earth’s interior, aside from that generated by the formation of the planet.

What are the 5 uses of heat energy?

Productive use of thermal energy involves a range of activities, such as cooking, drying, heating, smoking, baking, cooling and manufacturing.

How heat is useful in our daily life?

We use heat for many purposes in daily lives. Heat is used to warm your body on a cold morning. Heat can make things warm. Heat is used to cook food such as boiling water and frying eggs.

Why is heat important to Earth?

Heat inside the Earth from radioactive decay of elements and residual heat leftover from Earth’s formation. This heat drives plate tectonics and parts of the rock cycle. Earth’s internal heat is very important for processes that cause transformations from one rock type to another.

How can you say that heat convection is very useful to us?

The action of the running water transfers heat into the food faster. Mantle convection – The rocky mantle of the Earth moves slowly because of the convection currents that transfer heat from the interior of the Earth up to the surface. This is the reason the tectonic plates move gradually around the Earth.