Related Experiment Video
Updated: Jun 23, 2026
10:03
Uncoupling Coriolis Force and Rotating Buoyancy Effects on Full-Field Heat Transfer Properties of a Rotating Channel
Published on: October 5, 2018
Electrohydrodynamic convective heat transfer in a square duct
1LOTHAR (Low Gravity and Thermal Advanced Research Laboratory), Department of Energetics L. Poggi, University of Pisa, Pisa, Italy.
Annals of the New York Academy of Sciences
|May 12, 2009
Summary
Ion injection significantly enhances heat transfer in square ducts, improving efficiency for heat exchangers and heat sinks. This electrohydrodynamic flow technique boosts heat exchange capabilities while potentially reducing power needs.
Area of Science:
- Heat transfer enhancement
- Fluid dynamics
- Electrohydrodynamics
Background:
- Forced convection in ducts is crucial for thermal management.
- Existing methods for heat transfer augmentation have limitations.
- Ion injection offers a novel approach to enhance convective heat transfer.
Purpose of the Study:
- To investigate the effect of ion injection on forced convection in a square duct.
- To quantify the heat transfer augmentation achieved by ion injection.
- To assess the impact of ion injection on pressure drop.
Main Methods:
- Forced convection experiments in a square duct with bottom heating.
- Ion injection using high-voltage points with HFE-7100 as the working fluid.
- Liquid crystal thermography for local temperature measurements.
- Reynolds number range: 510 to 12,100.
Main Results:
- Ion injection dramatically augmented heat transfer, largely independent of flow rate.
- Both positive and negative ion injection were effective.
- Electrohydrodynamically induced flow increased pressure drop.
Conclusions:
- Ion injection is a highly effective method for enhancing heat transfer in forced convection.
- The technique shows promise for improving heat sink and heat exchanger performance.
- Potential benefits include reduced size and increased heat exchange capability with lower pumping power.
Related Concept Videos
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:14Mechanisms of Heat Transfer I
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
01:14Mechanisms of Heat Transfer
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
01:23Steady, Laminar Flow in Circular Tubes
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
01:20Conduction, Convection and Radiation: Problem Solving
There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...
01:19Mechanism of heat transfer
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...