What is heat transfer coefficient ?

What is heat transfer coefficient ?
by

1 Answer

Answer :

The method by which the molecules of a substance do not change their own position but simply give a molecule heat to its adjacent molecule by vibration and transfer heat from the warmer part to the cooler part of the substance is called heat transfer coefficient.
by

Related questions

A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2 .K. The Biot number is (A) 5.6 (B) 0.025 (C) 3.5 (D) 0.0035

Description : A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2 .K. The Biot number is (A) 5.6 (B) 0.025 (C) 3.5 (D) 0.0035

Last Answer : (B) 0.025

The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface) (A) K/h0 (B) 2K/h0 (C) h0 /K (D) h0 /2K

Description : The critical radius of insulation for a spherical shell is (where, K = thermal conductivity of insulating material h0 = heat transfer coefficient at the outer surface) (A) K/h0 (B) 2K/h0 (C) h0 /K (D) h0 /2K

Last Answer : (B) 2K/h0

The critical radius of insulation for cylindrical pipe is (where, hi = heat transfer coefficient at inside of the pipe) (A) K/h0 (B) 2K/h0 (C) hi /K (D) 2hi /K

Description : The critical radius of insulation for cylindrical pipe is (where, hi = heat transfer coefficient at inside of the pipe) (A) K/h0 (B) 2K/h0 (C) hi /K (D) 2hi /K

Last Answer : (A) K/h0

Overall heat transfer co-efficient of a particular tube is U1 . If the same tube with some dirt deposited on either side has coefficient U2 , then (A) U1 = U2 (B) U2 > U1 (C) U1 > U2 (D) U1 = dirt factor - U2

Description : Overall heat transfer co-efficient of a particular tube is U1 . If the same tube with some dirt deposited on either side has coefficient U2 , then (A) U1 = U2 (B) U2 > U1 (C) U1 > U2 (D) U1 = dirt factor - U2

Last Answer : (A) U1 = U2

For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) Decreases the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these

Last Answer : (C) Increases the overall heat transfer coefficient

What is a good approximation for the heat transfer coefficient of hydrocarbons inside 3/4″ tubes?

Description : What is a good approximation for the heat transfer coefficient of hydrocarbons inside 3/4″ tubes?

Last Answer : Use the following equation to estimate the heat transfer coefficient when liquid is flowing inside 3/4 inch tubing: Hio = 150./sqrt(avg. viscosity) Where: Hio (BTU/ft2-hr-0F Viscosity (cP) this is limited to a maximum viscosity of 3 cP

For a heat exchanger, will the overall heat transfer coefficient increase along with an increase in LMTD (log mean temperature difference) around the unit?

Description : For a heat exchanger, will the overall heat transfer coefficient increase along with an increase in LMTD (log mean temperature difference) around the unit?

Last Answer : The overall heat transfer coefficient is generally weakly dependent on temperature. As the temperatures of the fluids change, the degree to which the overall heat transfer coefficient will be affected depends ... with temperature as I've noted and the U-value will decrease over time with fouling).

Give the unit of overall heat transfer coefficient in SI and MKS.

Description : Give the unit of overall heat transfer coefficient in SI and MKS.

Last Answer : Unit of overall heat transfer coefficient 1. In SI : W/m2K 2. In MKS : kcal/hr m2K

Define film heat transfer coefficient.

Description : Define film heat transfer coefficient.

Last Answer : Film heat transfer coefficient: Film heat transfer coefficient h is defined as the quantity of heat transferred in unit time through unit area at a temperature difference of 10 between the surface and surrounding.

When hot liquid is poured into a thick glass tumbler, it cracks because glass – (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass – (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Last Answer : (1) is a bad conductor of heat so only inner surface expands Explanation: When hot liquid is poured into a thick glass tumbler, it cracks because glass is a bad conductor of heat so only inner surface expands.

Gas thermometers are more sensitive than the liquid thermometers because the gases – (1) have large coefficient of expansion (2) are lighter (3) have low specific heat (4) have high specific heat

Description : Gas thermometers are more sensitive than the liquid thermometers because the gases – (1) have large coefficient of expansion (2) are lighter (3) have low specific heat (4) have high specific heat

Last Answer : (1) have large coefficient of expansion Explanation: Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the has thermometer is more sensitive than liquid (mercury) thereto-meter.

Gas thermometers are more sensitive than the liquid thermometers because of the gases - (1) have low specific heat (2) have high specific heat (3) have large coefficient of expansion (4) are lighter

Description : Gas thermometers are more sensitive than the liquid thermometers because of the gases - (1) have low specific heat (2) have high specific heat (3) have large coefficient of expansion (4) are lighter

Last Answer : (1) have low specific heat Explanation: Gas thermometers are more sensitive because gas has low specific heat than liquids.

Gas thermometers are more sensitive than the liquid thermometers because the gases (1) have large coefficient of expansion (2) are lighter (3) have low specific heat (4) have high,specific heat

Description : Gas thermometers are more sensitive than the liquid thermometers because the gases (1) have large coefficient of expansion (2) are lighter (3) have low specific heat (4) have high,specific heat

Last Answer : have large coefficient of expansion

When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Last Answer :  is a bad conductor of heat so only inner surface expands 

Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed as the ratio of the concentration gradient at wall to the overall concentration difference (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2 (D) The z-component of the total mass flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz

Description : Pick out the wrong statement. (A) The Reynolds analogy for mass transfer is given by Lewis relation and is applicable, when Schmidt number is one (B) Sherwood number for flow in pipes can be expressed ... flux of a component A in binary mixture of A and B is given by - Dab'.dCA/dz

Last Answer : (C) According to film theory for equimolar counter diffusion, the mass transfer coefficient is given by DAB(B)P - 3, Q - 2

Mass transfer co-efficient is defined as (A) Flux = Co-efficient/concentration difference (B) Co-efficient = Flux/concentration difference (C) Flux=concentration difference/coefficient (D) None of these

Description : Mass transfer co-efficient is defined as (A) Flux = Co-efficient/concentration difference (B) Co-efficient = Flux/concentration difference (C) Flux=concentration difference/coefficient (D) None of these

Last Answer : (B) Co-efficient = Flux/concentration difference

H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S has to be reduced from 0.05 to 0.001 mole fraction in the gas side. The height of the tower (in metres) corresponding to an operating line given by, y = 5x + 0.001 is (A) 2.0 (B) 1.56 (C) 1.0

Description : H2S is being absorbed in a gas absorber unit. The height of the transfer unit based on the overall mass transfer coefficient on the gas side is 0.4 m. The equilibrium data is given by, y = 1.5 x. The bulk concentration of H2S ... by, y = 5x + 0.001 is (A) 2.0 (B) 1.56 (C) 1.0

Last Answer : (A) 2.0

What is the quickest form of heat transfer?

Description : What is the quickest form of heat transfer?

Last Answer : The quickest form would be through the transfer of energy in the form of electromagnetic radiation. Infrared Heating or Microwave Energy are examples of this. The radiation travels at the speed of light until the energy is absorbed in a material and you feel it as heat.

How does Transfer of heat energy from the sun to the moon take place?

Description : How does Transfer of heat energy from the sun to the moon take place?

Last Answer : – By radiation only

Transfer of heat energy from a heater coil to the cooking vessel takes place through the process of- (1) Convection only (2) Conduction and convection only (3) Radiation and convection only (4) Convection, conduction and radiation

Description : Transfer of heat energy from a heater coil to the cooking vessel takes place through the process of- (1) Convection only (2) Conduction and convection only (3) Radiation and convection only (4) Convection, conduction and radiation

Last Answer : (3) Radiation and convection only Explanation: Conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter; radiation is the transfer of energy with the help of electromagnetic waves.

Which of the following options correctly explains the term heat budget? (1) It is a mode of transfer of heat through matter by molecular activity. (2) It is the balance between incoming and outgoing radiation. (3) It is the radiation from the earth in the form of long waves. (4) It is the amount of heat which the surface of earth receives from the sun.

Description : Which of the following options correctly explains the term heat budget? (1) It is a mode of transfer of heat through matter by molecular activity. (2) It is the balance between incoming and outgoing radiation. ... waves. (4) It is the amount of heat which the surface of earth receives from the sun.

Last Answer : (2) It is the balance between in-coming and outgoing radiation. Explanation: Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both ... each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.

Which of the following are methods of heat transfer? (1) Convection (2) Evaporation (3) Revolution (4) Thermal Expansion

Description : Which of the following are methods of heat transfer? (1) Convection (2) Evaporation (3) Revolution (4) Thermal Expansion

Last Answer : (1) Convection Explanation: Convection is the transfer of heat from one place to another by the movement of fluids. It is usually the dominant form of heat transfer (convection) in liquids and ... the combined processes of conduction (heat diffusion) and advection (heat transfer by bulk fluid flow).

The study of phenomena at very low temperatures is called - (1) heat transfer (2) morphology (3) crystallography (4) cryogenics

Description : The study of phenomena at very low temperatures is called - (1) heat transfer (2) morphology (3) crystallography (4) cryogenics

Last Answer : (4) cryogenics Explanation: A person who studies elements that have been subjected to extremely cold temperatures is called a cryogenicist.

Heat transfer horizontally within the atmosphere is called – (1) Conduction (2) Convection (3) Absorption (4) Advection

Description : Heat transfer horizontally within the atmosphere is called – (1) Conduction (2) Convection (3) Absorption (4) Advection

Last Answer : (4) Advection Explanation: Convection transfers heat vertically into the atmosphere. In order for heat to be transferred to other regions, it must be transferred horizontally by the wind. The horizontal ... advection is the transport of pollutants or silt in a river by bulk water flow downstream.

Heat transfer by mixing is more commonly known as what?

Description : Heat transfer by mixing is more commonly known as what?

Last Answer : ANSWER: CONVECTION

Which of the following are methods of heat transfer? (1) Convection (2) Evaporation (3) Revolution (4) Thermal Expansion

Description : Which of the following are methods of heat transfer? (1) Convection (2) Evaporation (3) Revolution (4) Thermal Expansion

Last Answer : Convection

Which of the following options correctly explains the term heat budget? (1) It is a mode of transfer of heat through matter by molecular activity. (2) It is the balance between incoming and outgoing radiation (3) It is the radiation from the earth in the form of long waves. (4) It is the amount of heat which the surface of earth receives from the sun.

Description : Which of the following options correctly explains the term heat budget? (1) It is a mode of transfer of heat through matter by molecular activity. (2) It is the balance between incoming and outgoing radiation ... waves. (4) It is the amount of heat which the surface of earth receives from the sun.

Last Answer :  It is the balance between incoming and outgoing radiation

Heat transfer horizontally within the atmosphere is called (1) Conduction (2) Convection (3) Absorption (4) Advection

Description : Heat transfer horizontally within the atmosphere is called (1) Conduction (2) Convection (3) Absorption (4) Advection

Last Answer : Advection

What is the heat coefficient of resistance ?

Description : What is the heat coefficient of resistance ?

Last Answer : Answer : The coefficient of heat is the amount of radh that increases with the increase in temperature per ohm of radh.

The immunoglobulins are differentiated and also named on the basis of (A) Electrophoretic mobility (B) Heat stability (C) Molecular weight (D) Sedimentaiton coefficient like 7 S, 19 S etc.

Description : The immunoglobulins are differentiated and also named on the basis of (A) Electrophoretic mobility (B) Heat stability (C) Molecular weight (D) Sedimentaiton coefficient like 7 S, 19 S etc.

Last Answer : Answer : D

The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above

Description : The coefficient of performance is the ratio of the refrigerant effect to the (a) heat of compression (b) work done by compressor (c) enthalpy increase in compressor (d) all of the above

Last Answer : Ans: d

The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are (A) (COP)R = (COP)HP = 0.6 (B) (COP)R = 2.5; (COP)HP = 1.5 (C) (COP)R = 1.5; (COP)HP = 2.5 (D) (COP)R = (COP)HP = 2.5

Description : The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a ... )R = 1.5; (COP)HP = 2.5 (D) (COP)R = (COP)HP = 2.5

Last Answer : (C) (COP)R = 1.5; (COP)HP = 2.5

The coefficient of performance (COP) is the ratio between the:  A. Power consumption in watts and heat absorbed per hour  B. Heat absorbed per hour and the power consumption in watts  C. Work required and the absorbed heat  D. Absorbed heat and work required

Description : The coefficient of performance (COP) is the ratio between the:  A. Power consumption in watts and heat absorbed per hour  B. Heat absorbed per hour and the power consumption in watts  C. Work required and the absorbed heat  D. Absorbed heat and work required

Last Answer : Absorbed heat and work required

What refers to the amount of heat removed from the cooled space in BTS’s for 1 watt-hour of electricity consumed?  A. Cost efficiency rating  B. Energy efficiency rating  C. Coefficient of performance  D. Cost of performance

Description : What refers to the amount of heat removed from the cooled space in BTS’s for 1 watt-hour of electricity consumed?  A. Cost efficiency rating  B. Energy efficiency rating  C. Coefficient of performance  D. Cost of performance

Last Answer : Energy efficiency rating

What is a measure of the ability of a material to conduct heat?  A. Specific heat capacity  B. Coefficient of thermal expansion  C. Coefficient of thermal conductivity  D. Thermal conductivity

Description : What is a measure of the ability of a material to conduct heat?  A. Specific heat capacity  B. Coefficient of thermal expansion  C. Coefficient of thermal conductivity  D. Thermal conductivity

Last Answer : Thermal conductivity

What type of temperature coefficient material does not produce increased heat in response to increased current flow?

Description : What type of temperature coefficient material does not produce increased heat in response to increased current flow?

Last Answer : Zero-temperature coefficient.

Does anyone know the coefficient of friction for an A rated tire?

Description : Does anyone know the coefficient of friction for an A rated tire?

Last Answer : answer:I can't give you an exact number on that, but I the A traction grade is the second-highest rating given to a tire, AA being the highest. The traction grade applies to wet ... 'd see on a skidpad test. There, you have sidewall construction and vehicle characteristics to consider as well.

How to determine Axial Force Coefficient in Ansys Fluent ? -Physics

Description : How to determine Axial Force Coefficient in Ansys Fluent ? -Physics

Last Answer : I want to determine the aerodynamic coefficients of a 2D model (solid boosters). To be clear with the model, It is a 2D axisymmetric model, with blunt nose and flared aft body. There is a ... jet pressure ratio. Am I missing something or is there any other method to find axial force coefficient.

Define the performance coefficient of a refrigerator. ?

Description : Define the performance coefficient of a refrigerator. ?

Last Answer : : The ratio of heat removed from low temperature heat to work performed by an outside company is called the performance coefficient of the refrigerator.

What is the level of expansion coefficient ?

Description : What is the level of expansion coefficient ?

Last Answer : The levels of expansion coefficient are alpha , beta and gamma.

What is the unit of expansion coefficient ?

Last Answer : The unit of expansion coefficient is K ^ -1 .

What is elastic coefficient ?

Last Answer : The ratio of stress to distortion is called elastic coefficient.

What is the unit of elastic coefficient ?

Last Answer : The unit of elastic coefficient is Nm ^ -2 .

When a ring of metal is heated what happens to its hole? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion

Description : When a ring of metal is heated what happens to its hole? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion

Last Answer : (1) expands Explanation: The hole size will increase because in expansion the size between two molecules, do not increase so when the molecules on the outer edge move outward. Due to expansion, the ... expansion is the tendency of matter to change in volume in response to a change in temperature.

When temperature rises, resistance of negative temperature coefficient thermistor A. increases B. decreases C. zero D. infinity

Description : When temperature rises, resistance of negative temperature coefficient thermistor A. increases B. decreases C. zero D. infinity

Last Answer : decreases

Incorrect statement for co-efficient of friction could be that A. The coefficient of friction is denoted by the Greek letter µ. B. The coefficient of friction is directly proportional to the force of friction C. The coefficient of friction is constant even in the conditions of fast slipping and high contact pressure D. The coefficient of friction is inversely proportional to the force pressing the surfaces together

Description : Incorrect statement for co-efficient of friction could be that A. The coefficient of friction is denoted by the Greek letter µ. B. The coefficient of friction is directly proportional to ... D. The coefficient of friction is inversely proportional to the force pressing the surfaces together

Last Answer : The coefficient of friction is constant even in the conditions of fast slipping and high contact pressure

Ice skating is possible and practical because of a unique property of water. Is it because: w) The coefficient of kinetic friction of steel on frozen water decreases with decreasing temperature x) Ice readily sublimes y) The melting point decreases with increasing pressure z) Ice is a good thermal insulator

Description : Ice skating is possible and practical because of a unique property of water. Is it because: w) The coefficient of kinetic friction of steel on frozen water decreases with decreasing temperature x ... sublimes y) The melting point decreases with increasing pressure z) Ice is a good thermal insulator 

Last Answer : ANSWER: Y -- THE MELTING POINT DECREASES WITH INCREASING PRESSURE 

When a ring of metal is heated what happens to its hole ? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion

Description : When a ring of metal is heated what happens to its hole ? (1) expands (2) contracts (3) it expands or contracts according to its diameter (4) it expands or contracts according to its coefficient of expansion

Last Answer : expands