Fluid and Machinery Dynamics

The Institute's fluid and machinery dynamics program encompasses machinery and piping technology, structural dynamics, acoustics, multiphase and multicomponent flow, microgravity fluid dynamics, fluid and thermal systems diagnostics, and computational fluid dynamics. Investigations range from the development of space fluid systems, to research with gas industry consortia on advanced technology, to solving noise and vibration problems for automotive manufacturers and other industries.

The Gas Research Institute (GRI) Metering Research Facility (MRF) is located at the Institute and operated by Institute staff. This year, the MRF's research and commercial testing programs made significant contributions to the development of standards for gas industry operations. Ongoing GRI-sponsored research on ultrasonic flow meters produced data that contributed to American Gas Association Report No. 9, a de facto industry standard titled "Measurement of Gas by Ultrasonic Meters." The U.S. Department of Energy is funding further research on the performance of ultrasonic flow meters for underground gas storage applications. Another GRI research program provided significant technical data input to a revision of the American Petroleum Institute's (API) orifice meter installation standard. A critical evaluation of gas sampling techniques is being conducted with funding from GRI, the Minerals Management Service, and eight gas industry companies. In conjunction with the Southern Gas Association, MRF staff continue to develop training programs for the gas industry. In 1998, there were multiple offerings of a short course on gas meter station design and operation. The MRF remains the only test facility in North America at which high-accuracy, commercial natural gas flow meter development and calibration testing can be conducted on meter sizes from 2 to 20 inches. SwRI also offers field services to diagnose and solve problems at pipeline meter stations.

SwRI's valve fire test facility for many years has assisted the petroleum and chemical industries by providing testing and evaluation of valves and valve components that must maintain mechanical and leak integrity in a fire environment. Tests are conducted in accordance with American Petroleum Institute specifications for production and refinery equipment.

SwRI has initiated several technology assessments and data-gathering projects to enhance operational flexibility and reduce costs of gas compression. SwRI developed techniques under a Pipeline Research Committee International/GRI project to extract from public data cost information that will help guide maintenance and replacement decisions. SwRI developed new performance measurement techniques for the Gas Machinery Research Council (GMRC) and plans to use them in evaluating continuous capacity control technology that minimizes capital cost for high-speed, motor-driven reciprocating compressors. A GRI project will define and prioritize technologies needed for flexibility in future compression choices. Under a project for the INGAA Foundation, SwRI will study operational and cost factors that favor installation and use of motor-driven compressors. These projects will help the natural gas transmission, storage, and power generation industries respond to deregulation.

Many industries increasingly choose turbo-machines for compression, sometimes alongside older and very different reciprocating machines. While intended to improve costs, this poses new challenges for reliability and efficiency. For the gas transmission and storage industries, SwRI has refined techniques that optimize piping for smooth, stable operation, even with vastly different machines in close proximity. A GMRC assessment of techniques for active compressor control promises safe operation closer to surge, a dangerous condition of flow instability, and therefore a wider range of operation.

The U.S. natural gas industry increasingly uses high-speed, reciprocating compressors operating at 800 rpm or faster. High-speed machines offer both capital and operational cost advantages over older, slow-speed designs; however, it is much more difficult to measure the high-speed compressors' performance and efficiency. SwRI is working closely with the GMRC to develop new methods to overcome these difficulties. One early result of this research is a nonlinear acoustic model for measuring compressor cylinder pressures. The new model is able to extract true pressure readings from highly distorted signals caused by acoustic resonance effects. A unique feature is the model's ability to derive key acoustic parameters from the signal itself. No prior knowledge of the machine's interior gas passage geometry is required. The technology is expected to have a wide impact on industry as use of high-speed compressors increases.

The gas pipeline industry has long been plagued by "black powder" production. The problem is so pervasive that efforts to control and clean the powder from pipelines are considered a routine cost of business. A multiyear research program by the Institute for the GMRC has identified the powder as primarily composed of various species of iron oxide. It also has established the root causes of powder formation, including both a chemical and a microbial source. Methods for its detection in pipelines and for its mitigation have also been determined. Armed with this information, the industry is becoming equipped with the tools and knowledge to deal more effectively with black powder and is aware of the potential cost savings from controlling black powder at its several sources rather than dealing with it after the fact.

SwRI researchers in 1998 completed the fourth year of research to help operators of large reciprocating compressors and engines troubleshoot, design, and build more reliable foundations and mountings. Over this period, the research focus has moved from foundation design issues, to crankshaft protection methods, to epoxy chock material properties, and finally to anchor bolt design and applications. Results of this GMRC-sponsored research have been published in a series of technical reports, which are available in electronic form via the Internet at www.gmrc.org.

As the oil and gas production industry develops deepwater fields in the Gulf of Mexico, one major concern is the formation of hydrate and paraffin blockages in multiphase flow pipelines caused by combinations of low temperatures and high pressures. The Institute is playing a major role in formulating an approach to this problem that is being considered by the DeepStar industry consortium. SwRI has built a unique multiphase flow facility to reproduce hydrate-forming conditions in the laboratory. This facility is used to study hydrate agglomeration and to design a field-scale hydrate test facility. In addition to hydrate-related projects, the Institute is investigating concerns related to production separators. These devices are a key element in the economical production of wellstreams that involve oil, gas, water, and solid components. SwRI is conducting research for major oil and gas companies to provide lighter and smaller production separators to provide a technical basis for dealing with foam and mist in a separator and to evaluate the use of internal structure to improve separator performance.

Oil and gas companies constantly seek to produce oil faster, better, and cheaper. Multilateral well technology, where branches are drilled from a parent wellbore, is an attractive, but complex process for accomplishing these multiple objectives. SwRI identified a number of innovative concepts to enhance the functional performance and reduce the risk of drilling and producing operations in reservoirs completed using multilateral wells. The most promising ideas have been developed into conceptual designs for further evaluation and definition by a consortium of oil companies. For a similar project, the Institute was asked to develop solutions to a critical problem in production of excess natural gas. In both studies, a multidisciplinary team of investigators from throughout the Institute was brought together to integrate solutions from outside the traditional oil and gas industry technology base.

NASA's Human Exploration and Development of Space (HEDS) Enterprise is exploring the potential of sending humans to Mars in the next decade. A critical technology required for improving the logistics of such a flight is the use of local resources. In Situ Propellant Production (ISPP) is under study for generating rocket fuel for the return trip to Earth. During the past year, the Institute has evaluated a broad range of technical approaches to accomplishing this, such as developing models to predict the performance of these ISPP plants and recommending the most promising methods of producing both the rocket fuel and oxidizer. SwRI engineers assessed chemical and separation processes and dust filtration methods. The Institute performed a similar study involving use of ISPP technology to produce propellants from lunar soil to support a potential future mission to the lunar surface. To complement these NASA-funded efforts, SwRI is conducting internal research to investigate new approaches to converting martian atmospheric carbon dioxide to oxygen for use as rocket oxidizer. These approaches would require significantly less power than methods currently being considered by NASA.

Although work began in the early 1970s on the SwRI helmet test facility, its monorail helmet drop is still recognized as the standard for impact compliance testing of a wide variety of helmet types. The facility has maintained state-of-the-art mechanical test and data acquisition systems to allow continued testing programs for the U.S. Department of Transportation and commercial helmet manufacturers. SwRI has also played a leading role in developing standards for a wide variety of helmet types, currently focused on the Headgear and Helmets Subcommittee of ASTM F08 on Sports Equipment and Facilities.

Noise sources from high-speed rotating machinery are identified using acoustic intensity measurement techniques in SwRI's large acoustic test facility. Institute engineers conduct such studies to develop control measures or redesigns to reduce noise to acceptable levels in industrial equipment and vehicles.

The harsh thermal and vibration environment in which catalytic converters operate requires knowledge of their component material properties under in-service conditions. Fatigue characteristics of materials that insulate the converter canister from the high-temperature substrate are important to meeting a 100,000-mile design goal. SwRI has developed a dynamic test apparatus to study the high-temperature fatigue characteristic of converter insulating materials. The test apparatus can maintain 1,000°C substrate and 800°C canister temperatures while imparting high levels of relative motion between the canister and substrate, thereby subjecting the insulating material to a fatigue-causing environment.

The loss of communications during and immediately following an earthquake can be catastrophic in terms of emergency response. SwRI assists the telecommunications industry by providing testing using a seismic simulator that can apply realistic earthquake motions in two axes simultaneously to determine equipment robustness and susceptibility to failure during seismic events.

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