What you'll learn

Understand the physical mechanism of convection, and its classification
Visualize the development of velocity and thermal boundary layers during flow over surfaces
Gain a working knowledge of the dimensionless Reynolds, Prandtl, and Nusselt numbers
Distinguish between laminar and turbulent flows, and gain an understanding of the mechanisms of momentum and heat transfer in turbulent flow
Evaluate the heat transfer associated with flow over a flat plate for both laminar and turbulent flow
Calculate the the average heat transfer coefficient for flows over cylinders and spheres during cross flow
Have a visual understanding of different flow regions in internal flow, such as the entry and the fully developed flow regions
Analyze heating and cooling of a fluid flowing in a tube under different conditions, and work with the logarithmic mean temperature difference
Determine the friction factor and Nusselt number in fully developed turbulent flow using empirical relations, calculate the pressure drop and heat transfer rate
Understand the physical mechanism of natural convection
Evaluate the Nusselt number for natural convection associated with vertical, horizontal, and inclined plates as well as cylinders and spheres

Course content

5 sections • 36 lectures • 5h 31m total length

The Thermal Boundary Layer15:16
Example 13:26
Show how the average convection coefficient over a flat plate relates to the local coefficient, with achbar = 1.11 hx, computable by evaluating the local coefficient at position x.
Laminar and Turbulent Boundary Layers18:01
Example 29:02
Examine water flow over a flat plate, derive the average convection coefficient by integrating laminar and turbulent zones, and show how temperature-dependent water properties affect convection.
The Prandtl Number6:52
The Nusselt Number4:45
Introduce the Nusselt number, a dimensionless ratio of convective to conductive heat flux, quantifying heat transfer enhancement due to fluid motion.
Example 311:27

The Empirical Method7:34
Apply the empirical method to determine convection coefficients by relating average Nusselt numbers to Reynolds and Prandtl numbers through geometry-specific correlations and heated surface experiments.
External Flow Correlations: Flat Plate17:54
Derive convection coefficients and boundary layer thickness for external flow over a flat plate using laminar and turbulent correlations. Determine regimes via Reynolds numbers and estimate heat transfer.
Example 110:12
Example 212:43
Example 2 analyzes a refrigerated truck roof with aluminum panels and 50 mm insulation under 105 km/h wind and solar radiation to compute the outer surface temperature and heat load.
Cylinder in Cross Flow13:44
Explore the cylinder in cross flow, including stagnation pressure, pressure gradients, boundary-layer development, separation, and how Reynolds and Prandtl numbers determine average convection coefficients with correlations.
Example 35:19
Compute the heat transfer rate per unit length from a steam pipe to air using the Chirchir correlation for the average convection coefficient, based on Reynolds and Prandtl numbers.
External Flow Correlations: The Sphere2:35
Study external flow over a sphere, including boundary layer transition and separation with wake mixing. Apply the Whiteaker correlation to estimate the average convection coefficient.
Example 47:30
Compute the cooling time from 75°C to 35°C for a copper sphere in air at 10 m/s and 23°C using the capacitance method, checking Biot number and convection heat transfer.

Hydrodynamic Considerations7:37
examine how a circular pipe develops a velocity boundary layer, transitioning from laminar to fully developed flow; compare laminar and turbulent profiles, Reynolds number criteria, and hydrodynamic entry lengths.
Velocity Profile in the Fully Developed Region11:18
Derive the fully developed laminar velocity profile in a circular pipe, showing a parabolic u(r) and the relation to mean velocity via u(r)/u_mean = 2(1 - r^2/a^2).
Pressure Gradient and Friction Factor in Fully Developed Flow13:47
Thermal Considerations11:45
Thermally Fully Developed Flow10:10
Examine thermally fully developed flow, detailing axial temperature profile evolution, dimensionless temperature independence from x, and a constant, x-independent local convection coefficient in the fully developed region.
Constant Surface Heat Flux Condition7:58
Explain the constant surface heat flux condition using a differential control volume and area energy balance, showing mean temperature rises linearly with x in the thermally fully developed region.
Constant Surface Temperature Condition12:10
Example 110:20
Compute the length needed to heat water from 20 to 60 C in a tube using energy balance with volumetric generation, and assess fully developed flow and outlet convection.
Example 24:15
Calculate the water convection coefficient in a 50 mm, 6 m condensing steam tube, with water from 15 to 57 C, LMTD 61.63 C, h ≈ 755 W/m^2K.
Surface Thermal Condition: External Fluid8:36
Analyze surface thermal condition with external fluid and moving fluid to infinity, using an overall heat transfer coefficient to combine outer convection, conduction, inner convection, and log mean temperature difference.
Internal Flow Correlations7:52
Explore internal forced convection correlations for laminar and turbulent flow in circular and noncircular ducts, applying laminar Nu values and boulter, Sieder–Tate, and New Leonski models across Reynolds ranges.
Example 39:04
Compute the resistance heater power to heat water from 15 to 65 C in a 3 cm, 5 m tube with uniform surface heat flux; estimate the end-surface temperature.
Example 415:50
Analyze heat transfer in a 10 m insulated pipe carrying water vapor, calculate the overall heat transfer coefficient, and verify the insulation keeps the outer surface below 45 C.
Example 59:32
Compute exit temperature and heat loss for air entering a 0.2 m square duct at 80 °C with 60 °C walls, yielding exit ≈71.3 °C and heat loss ≈1.31 kilowatts.

Flow and Thermal Considerations10:14
Explore natural convection around a heated vertical plate, driven by buoyancy from temperature-induced density differences, with boundary-layer development and velocity profiles, and how buoyancy affects the convection coefficient.
The Grashof Number8:53
Natural Convection Correlations7:12
Learn to compute average natural convection coefficients for vertical and horizontal plates, cylinders, and spheres using Churchill correlations and geometry-specific characteristic lengths.
Example 15:10
Analyze natural convection from a vertical glass panel between a fireplace and a room, yielding Nu ≈ 147 and a heat transfer rate of about 1.06 kW.
Example 27:21
In example 2, an aluminum plate with electrical components dissipates power; energy balance shows convection and radiation losses, giving a maximum of about 583 W to stay below 77 C.
Example 36:00

Requirements

Fundamentals of Heat Transfer Part 1
Fundamentals of Engineering Thermodynamics
Fundamentals of Fluid Mechanics

Description

Welcome to Fundamentals of Heat Transfer Part 2: Enhance Your Understanding of Convection and Convection Coefficients

In part 1 of our course on Fundamentals of Heat Transfer, we focused on heat transfer by conduction and briefly discussed convection as a possible boundary condition. In part 2, we delve deeper into convection and convection coefficients.

Our first objective is to develop an understanding of boundary layer phenomena and the features that control the convection coefficient. We will discuss the hydrodynamic boundary layer concept and the thermal boundary layer, which is the region of the fluid next to the surface in which energy exchange is occurring, and examine its influence on the convection coefficient.

We then address the problem of convection and introduce methods for estimating convection coefficients associated with forced convection in external and internal flows. We also consider free or natural convection and present methods for estimating convection coefficients for common geometries.

Throughout the course, we will explore how to estimate convection coefficients to perform analyses on thermal systems experiencing different types of flow and heat transfer situations. We will examine how the convection coefficient depends upon fluid properties, surface geometry, and flow conditions.

By the end of this course, you will have an enhanced understanding of convection and convection coefficients, enabling you to apply these concepts in real-world scenarios.

We wish you good luck in your learning journey. Enroll now to advance your knowledge of heat transfer!

Who this course is for:

Engineering Students

What you'll learn

Explore related topics

Course content

Introduction to Convection7 lectures • 1hr 9min

External Forced Convection8 lectures • 1hr 18min

Internal Forced Convection14 lectures • 2hr 20min

Natural Convection6 lectures • 45min

Exercise Files1 lecture • 1min

Requirements

Description

Who this course is for: