Tag Archives: air flow

Next Webinar “Natural Convection Cooling: Optimizing Heat Sink Fin Spacing and More for Heat Transfer”

The better educated you are about implications of heat in electronics, the better prepared you are when heat problems inevitably occur and the more valuable you will be perceived at your company. Advanced Thermal Solutions breaks down the often complex field of thermal management into individual, key topics that are more easily understood and mastered. Our next webinar, Natural Convection Cooling: Optimizing Heat Sink Fin Spacing and More for Heat Transfer, is on Thursday, November 29, 2012 at 2pm EST.

Most high-powered electronic devices are cooled by forced convection airflow, but occasionally there is a need for natural convection cooling. Determining factors, which include cost, noise, vibration and reliability, can cause the need to eliminate the use of a fan or blower – particularly in consumer electronics and outdoor enclosures. Attendees will learn more about how to implement natural convection cooling, how to optimize for fin spacing and other important design elements for a successful thermal management solution.

Register Now for the free webinar “Natural Convection Cooling: Optimizing Heat Sink Fin Spacing and More for Heat Transfer” on Thursday, November 29, 2012 at 2pm EST.

In the meantime, check out the article on “Natural Convection in Vertical Channels” from Qpedia to see how techniques for optimizing heat transfer in natural convection situations.

 

Performance Differences between Fan Types Used for Electronics Cooling

Billions of fans are now in use for active cooling of PCBs and other hot electronic components. An article in Qpedia, the thermal e-magazine from Advanced Thermal Solutions, Inc., (ATS), explores the two most common types of fans used in electronics cooling: the radial (or centrifugal) fan and the axial fan.

The difference between the axial fan and radial fans can be divided into two parts, namely geometry and fluid dynamics.

An axial-flow fan has blades that force air to move in a parallel direction to the shaft around which the blades rotate. For a radial fan, the air flows in on a side of the fan housing, then turns 90 degrees and accelerates, due to centrifugal force as it exits the fan housing. These differences in air flow direction have design implications. For example, a radial fan can blow air across a PCB more efficiently, and use less space, than mounting an axial fan to blow air down onto a board.

The fluid flow rate through an electronics system, e.g., enclosure, is determined by the intercept between the fan and system curves that plot the air pressure drop over volumetric flow rate. A system’s air flow curve can be calculated using 1D fluid mechanics, or it may require the use of high performance CFD or experimental data. In general, for the same power and rotation speed, the radial fan can achieve a higher pressure head than an axial fan. However, an axial fan can achieve a higher maximum flow rate than a radial fan.

In theory, this same approach applies when using two fans in series or in parallel. When the fans are in series, the maximum flow rate should stay the same as for the single fan, but the maximum pressure head doubles. When using two fans in parallel, the maximum pressure head should remain the same as for the single fan, but the flow rate doubles. In real situations, though, the fans may interfere with each other, thus providing lower than expected results. Thus, actual experimentation is typically needed.

Download the Full ATS White Paper Performance Differences Between Fans and Blowers and Their Implementation

What are Fan Laws and how do you use them in thermal management design?

During a product’s life cycle a redesign may be carried out which replaces older components with new, higher powered ones. Due to the resulting higher heat flux, increased thermal management is often needed to maintain adequate component junction temperatures and reduce temperature rise within the system.  Fan Laws are useful mathematical tools to understand, compare and contrast different fan approaches.  Using Fan Laws before choosing a fan can help engineers to make solid choices to reduce cost, experimentation and time to market.  ATS’s five-page presentation on Fan Laws for thermal management which includes examples on how to use them, is a good introduction to this important engineering tool:



Tony Koryban Mail Bag Archives: Which is a better fan thermal management strategy? Push air into your chassis or pull it out?

Our readers know of Tony Koryban.   He always has an interesting take or two on thermal engineering and on the topic of fans in thermal management he’s not silent.  Tony receieved this question in his mailbag on fan use and it’a an age old question:

Dear Tony,

Which is better, mounting a fan at the inlet of my chassis so it pushes the air in, or at the outlet, so it draws the air out?

Hobson
from Quandary, Minnesota

What’s your guess? Or what’s your standard practice?  Let’s give Tony a chance to answer by clicking to his answer at this link here:   Tony Koryban Mailbag Archives

…. and don’t forget, you can see Tony in person, at Cooling Zone 2010

ATS, Inc. announces “on demand” Webinar for Thermal Engineers: Methodologies for Fan Characterization

ATS, Inc. is announcing a new “on-demand” webinar from our thermal engineering team, “Methodologies for Fan Characterization”.  This webinar is ready for download and listening 24 hours  day from the ATS web site.

Topics covered include:

  • What are the fan types and points of application?
  • Understanding how fans operate and the effect of bypass flow on their operation
  • Fan selection
  • Fan assemblies and their implementation
  • Use of fan laws for sizing
  • Managing acoustic noise
  • Fan characterization

To take part in this webinar, just click to our site to reach the webinar at: Methodologies for Fan Characterization