Heat rate and heat flux

• What are the units for heat flux?

  Units for heat flux are Btu/hr-ft2. The heat flux can be determined by dividing the heat transfer rate by the area through which the heat is being transferred. ̇ Q Q ̇ ̇ Q = heat flux (Btu/hr-ft2) ̇ Q = heat transfer rate (Btu/hr)

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• Does heat transfer change as heat flux increases?

  Four regions are represented in Figure 13. The first and second regions show that as heat flux increases, the temperature difference (surface to fluid) does not change very much. Better heat transfer occurs during nucleate boiling than during natural convection.

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• What is the heat flux of a copper ball?

  The heat flux can vary with time, temperature, and position. 10 cm diameter copper ball is to be heated from 100°C to 150°C in 30 minutes. ρ = 8950 kg/m3 and C = 0.395 kJ/kg°C. What is: a) the total amount of heat transfer to the ball, b) the average heat transfer rate, and c) the average heat flux at the ball surface?

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• What happens if a critical heat flux is exceeded?

  For example, in a reactor, if the critical heat flux is exceeded and DNB occurs at any location in the core, the temperature difference required to transfer the heat being produced from the surface of the fuel rod to the reactor coolant increases greatly.

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• [PDF File]HEAT TRANSFER EQUATION SHEET - UTRGV

  https://info.5y1.org/heat-rate-and-heat-flux_1_eb0d53.html

  1 HEAT TRANSFER EQUATION SHEET Heat ConductionRate Equations (Fourier's Law) Heat Flux: 𝑞𝑞 𝑥𝑥′′ = −𝑘𝑘 𝑑𝑑𝑑𝑑 𝑑𝑑𝑥𝑥 𝑊𝑊 𝑚𝑚 2 k : Thermal Conductivity 𝑊𝑊 𝑚𝑚∙𝑘𝑘 Heat Rate: 𝑞𝑞 𝑥𝑥 = 𝑞𝑞 𝑥𝑥′′ 𝐴𝐴 𝑐𝑐 𝑊𝑊 A c : Cross-Sectional Area Heat Convection Rate Equations (Newton's Law of Cooling) Heat Flux: 𝑞𝑞 = ℎ(𝑇𝑇 𝑠𝑠 −𝑇𝑇 𝑊𝑊 𝑚𝑚 2 h :

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• [PDF File]Staedy Conduction Heat Transfer - Simon Fraser University

  https://info.5y1.org/heat-rate-and-heat-flux_1_6a931c.html

  Convection involves the transfer of heat by the mixing and motion of macroscopic portions of a fluid. Radiation, or radiant heat transfer, involves the transfer of heat by electromagnetic radiation that arises due to the temperature of a body. Heat flux is the rate of heat transfer per unit area.

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• [PDF File]THERMODYNAMICS,THERMODYNAMICS, HEAT HEAT TRANSFER,TRANSFER ...

  https://info.5y1.org/heat-rate-and-heat-flux_1_155ec3.html

  • Heat Rate (q) –Instantaneous heat flux at a point on the vehicle (W/cm2) • Heat Load (Q) –Integration of heat rate with time over a trajectory (J/cm2) • Convective Heating –Heat flux to the vehicle from conduction ( gradT) • Catalytic Heating –Heat flux to the vehicle due to surface facilitated chemical reactions

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• [PDF File]010408 ChE120B W08HeatTrans-v4 - UC Santa Barbara

  https://info.5y1.org/heat-rate-and-heat-flux_1_d2717b.html

  The rate of heat flow is proportional to the difference in heat between two bodies. A thin plate of thickness z with temperature difference ∆T experiences heat flow Q: where ∆ T = − k z units: W/m2 or J/m2s is a proportionality constant called the thermal conductivity (J/msK):

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• [PDF File]Lecture 2 Intro to Heat Flow - UC Santa Barbara

  https://info.5y1.org/heat-rate-and-heat-flux_1_6e698e.html

  The rate of heat transfer per unit area is called heat flux, and the average heat flux on a surface is expressed as W /m2 A Q q Steady Heat Conduction in Plane Walls Conduction is the transfer of energy from the more energetic particles of a substance to

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• [PDF File]Lecture #1: Stagnation Point Heating - NASA

  https://info.5y1.org/heat-rate-and-heat-flux_1_94d3bd.html

  Mar 28, 2009 ·

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