The Tenth Drop in the Pitch Drop Experiment

image of pitch drop experiment

The pitch drop experiment
© Image published with the permission of the University of Queensland

The Pitch drop experiment was initiated in 1927 at the University of Queensland, Australia. It consists of observing the very slow flow of a highly viscous material through a convergent, under gravity effect. In this experiment, one drop grows and falls within about a decade.

The ninth drop has fallen in April 2014; it needed about 14 years to grow and fall. One may wonder when the tenth drop will fall. Although the key material property, the viscosity, is difficult to measure, it is possible to perform a numerical simulation with ANSYS POLYFLOW software. The very long time interval involved in the experiment suggests using the month as time unit, instead of the second as is usually the case for transient cases. Of course, this requires converting the physical data accordingly. The calculation involves not only the motion of the drop from the conical reservoir into the channel; it also incorporates the development of the pitch drop under the channel exit; this is an important ingredient to the mechanism of the drop formation. Continue reading

Improving Performance and Durability of Heat Exchangers

image of heat exchangers with vapor volume fraction

Vapor Volume Fraction in EGR Cooler Due to Boiling

Heat exchangers are among the most common process equipment. They come in different sizes (e.g. cold plate within your mobile phone vs a waste heat recovery system in a plant), shapes (shell and tube, tube in tube, plate and frame, for example) and types (recuperative and regenerative).

Although many heat exchangers have been thoroughly studied, analyzed and even optimized, the need to improve heat exchanger performance, reduce their capital and running costs, and increase their durability will never end. Continue reading

Coupling Piezoelectric and Fluid Simulations

ink jet nozzle

Ink jet nozzle

Piezoelectric devices surround us in our everyday life. Our cars and trucks contain many piezoelectric devices, including fuel level sensors, air bag deployment sensors, parking sensors and piezoelectric generators in the wheels to power the tire pressure monitoring system. Your smartphones or tablet contains piezoelectric sensors that detect the motion and orientation of the device, which my kids were using to good effect to play “Need For Speed” yesterday. Many of us have ink jet printers at home, which can use piezoelectric printer heads to eject thousands of drops per second. Continue reading

How Bioreactors Are Keeping Cells Happy

image of mixing tank velocity surface cell bioreactor

Velocity iso-surface colored by Eddy viscosity

Cell-culture bioreactors lie at the heart of the processes used to produce large-molecule, protein-based therapeutics. In cell culture, mammalian cells are grown outside the human/plant body. These cells produce therapeutic proteins and antibodies. This is much easier said than done. In fact, cells do not cooperate much when they are grown outside the (human or plant) body. The question then is: Why is it so difficult for cells in culture to have the same physiological function in laboratory as in our body? Continue reading

Meeting CAFE standards Through Improved Engine Simulations

The U.S. Environmental Protection Agency (EPA) recently released new Corporate Average Fuel Economy, or CAFE standards for light duty cars and trucks. These standards are designed to reduce greenhouse gas emissions and improve fuel economy, leading to model year 2025 vehicles that will emit just one-half the greenhouse gasses that model year 2010 vehicles do.

To reach these ambitious goals, the new CAFE standards mandate that automakers raise the average fuel efficiency of new cars and trucks to 54.5 miles per gallon by 2025. These are lofty and commendable goals. But for engine designers and automakers, are the new standards even feasible for real-world vehicles? The EPA believes they are, and has established a new program to prove it. Continue reading

Master’s Degree in Numerical Simulation in Engineering with ANSYS

For several years, I have seen engineers working in the industry or finishing their degree in engineering that have been looking for advanced education in ANSYS.
Some of them were unable to find a course with enough specialization, without the restrictions of classroom training, or with certified content from ANSYS.

numerical simulation Madrid with ANSYSNow, the Technical University of Madrid (UPM) has responded to this request by organizing, in collaboration with ANSYS, an online master’s degree with the goal of training experts in fluid mechanics and solid mechanics numerical simulation using ANSYS engineering tools. Continue reading

Readers Choice for Top 5 ANSYS Advantage Articles

I enjoy working on every article I coordinate for ANSYS Advantage magazine. I always learn something new while assisting ANSYS customers and staff tell their stories of excellence in engineering simulation. I have no favorites as I appreciate all of the articles. But, I decided to let our readers choose their top five, based on the power of downloading. The following are the most-read articles from the four issues (three regular issues and one special issue for oil and gas) of ANSYS Advantage published last year. All these stories have one thing in common: They feature robust and reliable design practices. Drumroll please …

Continue reading

Submodeling of Composites Laminate Structures Using ANSYS Composite Prepost 15.0

Delamination or interlaminar fractures of composite laminates are generally caused by high interlaminar stresses that arise due to mismatch in elastic properties between plies and at free edge. Therefore, understanding the behavior of these stresses is of critical importance in the assessment of structural integrity of composite materials and structures. Continue reading