Winds of Change

Tuesday, December 20, 2011

By Jean Florman

When Pablo Carrica feels the wind sail across the Iowa prairie and tumble through the streets and buildings of Iowa City, he thinks of opportunity—for the country, the state, and especially for his students. As the United States continues to grapple with its energy needs, Iowa has moved into a position of leadership in the development and production of wind energy, and Carrica wants University of Iowa engineering students to seize this opportunity to help enhance this important renewable energy resource.

In 2009, the associate professor of mechanical and industrial engineering and research engineer at IIHR-Hydroscience & Engineering helped the University of Iowa acquire and set up a small wind turbine that he now uses to teach experimental methods and procedures to UI engineering students. Purchased with a $20,000 collegiate teaching grant and located on campus a few blocks from the college, the three-blade Skystream 3.7 turbine can generate 2.4 kW of power—the ideal size for teaching purposes. To provide instrumentation for the device, Carrica secured almost $40,000 in grant funds from the Iowa Alliance for Wind Innovation and Novel Development (IAWIND). Carrica’s students have conducted a variety of experiments that measure wind speed, power, and rotation of the turbine blades in an effort to calculate mechanical and electrical efficiency of the device.

“I want my students to get hands-on engineering experience,” Carrica says. “The turbine allows them not only to learn about the mechanics of energy production but also to appreciate the importance of wind power for our future.”

When Pablo Carrica feels the wind sail across the Iowa prairie and tumble through the streets and buildings of Iowa City, he thinks of opportunity— for the country, the state, and especially for his students. As the United States continues to grapple with its energy needs, Iowa has moved into a position of leadership in the development and production of wind energy, and Carrica wants University of Iowa engineering students to seize this opportunity to help enhance this important renewable energy resource.

Iowans also are beginning to appreciate that resource, and Iowa companies are tapping into the growing wind energy market. The state ranks first in the generation of wind power per individual as well as first in overall wind-generated electricity, with 17% of our electricity produced by wind. Several significant wind energy companies call Iowa home, including blade factories in Newton and Fort Madison, turbine manufacturing plants in Cedar Rapids and West Branch, and tower production facilities in Newton and Sioux City.

“Wind energy is relatively low-tech, but the industry is ripe for innovation and growth,” says Carrica, who hopes to erect his own turbine for home use some day.

Students in Carrica’s senior-level Experimental Engineering course who choose to experiment on the turbine work in three-person teams explore a range of questions, including how transient forces on the six-foot-long fiberglass blades affect the gearbox, the relationship between the speed of rotation and the generation of electricity, and the degree to which the blades’ movement impacts the shaft. As the students measure a range of variables over time, the data is fed into a computer for future analysis. The 37-foot-tall turbine tower is hinged so students and researchers can periodically change the instrumentation located in the nose or in the nacelle, the lozenge-shaped housing behind the nose, as well as gain access to the gearbox, also located in the nacelle.

Located just west of the University Services Building (USB), the turbine generates a small amount of power which is transmitted to the power panel in the USB Energy Control Center. In the future, additional green energy technologies on campus will include a solar E-car charging station, photovoltaic/solar panels near the new Cambus Maintenance facility, and expansion of the biomass energy program at the UI Power Plant.

Carrica notes that despite the small output of the turbine, it is an important symbol of the Iowa’s commitment to sustainability as well as an innovative teaching tool that underscores the College’s dedication to hands-on student learning that address real-world needs.

His students agree. As a junior, Michael Carbone completed Experimental Engineering the semester before the turbine was installed, but when Carrica invited him to work as an undergraduate assistant the following year, this young mentee jumped at the opportunity.

“Students in the course learn fundamental data collection and data reduction techniques, as well as how to transform that data into something meaningful,” says Carbone, who is earning a Master’s degree in mechanical engineering at Iowa. They also better understand the importance of experimental validation as an important step in computer simulation.”

Graduate teaching assistant Yuwei Li adds that both undergraduate and graduate students who work with the turbine learn how to turn their ideas into reality.

“Because the turbine is a real machine and product students gain a direct understanding about how a real machine works instead of just studying it on paper,” says the PhD candidate in mechanical engineering. “They also learn how to implement their ideas to solve problems. What instrument will work best and why? Should we use wireless? What factors will affect the measurements, and how can the data best be transferred to the computer? There are no written instructions telling them how to finish their lab—they have to accomplish that effort by themselves.”

Li adds that the solid theoretical and practical knowledge that students acquire by working with the wind turbine will help them better understand the complicated—but promising—field of wind energy. And it’s a subject that may encourage them to cross disciplinary boundaries, much like their professor Pablo Carrica was lured into the field of computational fluid dynamics.

Educated as a nuclear engineer, Carrica became intrigued by computational fluid dynamics, ship hydrodynamics, and aerodynamics. Like generations of budding engineers before him who built crystal radio sets, tinkered with erector sets, and constructed sturdy Lincoln Log cabins, the young Carrica channeled his childhood fascination with the workings of the world into the creation of Lego™ machines, buildings, and cities.

Today, he applies those design and analytic skills to create and test computational fluid dynamics codes for experimental deep water offshore wind turbines.

“I want to develop tools that are efficient and useful and to help my students do the same,” says Carrica, who recently received a $101,000 grant from the National Science Foundation to study simulation-based design for deep water offshore wind turbines. “I focus on parameters such as optimal pitch—the angle of the turbine blades for a given wind speed as it relates to power output. I’m also interested in answering questions about the fluid dynamics of ship design that will help companies analyze the effectiveness of the floating offshore towers that support wind turbines.”

Through both his research and teaching, the UI professor works to encourage his students to consider wind energy as an important resource to develop a sustainable world. Although wind energy currently satisfies only about two per cent of the US demand for electricity, Carrica is optimistic that research and development can meet the US Department of Energy’s goal to satisfy 20 per cent of that need in the near future. And if some of his students are part of that effort,he will have met one of his own goals as a teacher and mentor.