Curtt N. Ammerman

Assembly, Commissioning and Operation of the NHMFL 100 Tesla Multi-Pulse Magnet System

The U.S. National High Magnetic Field Laboratory 100 Tesla multi-pulse magnet system is now successfully commissioned. This magnet system is the result of a long-term partnership project jointly funded by the U. S. Department of Energy - Office of Basic Energy Science and the National Science Foundation. Science experimentation inside the magnet started in December 2006 at the NHMFL Pulsed Field Science Facility located at Los Alamos National Laboratory. Repeated, non-destructive operation of the system with original components is continuing in the 85 T to 90T range. The system will eventually combine a nominal 40 T platform field produced by a controlled-waveform generator-powered long-pulse magnet with a nominal 60 T field generated by a capacitor-bank powered pulsed insert magnet to produce the rated field. Milestone non-destructive operation to 88.9 T was achieved in October 2006. This paper will present an overview of the generator driven outsert magnet system together with the high-field pulsed insert magnets design and construction. We will review commissioning and performance data through summer of 2007. Criteria for increasing the systems maximum field performance will also be reviewed addressing the goal to increase operating field level (in support of experiments) to 95 T and then to 100 T.

The U.S. NHMFL 100 Tesla multi-shot magnet

The design, analysis and fabrication progress of the 100 T Multi-Shot Magnet is described. The description includes the structural analysis of the outer coil set, the fabrication of the 100 T prototype coil 1, the fabrication of a coil 1 test shell, and the analysis of the electrical busbar assembly. Fabrication issues and their solutions are presented. This magnet will be installed as part of the user facility research equipment at the U.S. National High Magnetic Field Laboratory (NHMFL) Pulsed Field Facility at Los Alamos National Laboratory.

A New Microporous Surface Coating for Enhancement of Pool and Flow Boiling Heat Transfer

Publisher Summary This chapter focuses on the development and the performance enhancement associated with the microporous coating in nucleate pool and flow boiling of highly wetting fluids, which are inert, dielectric, and can have low boiling points making them desirable for electronics cooling applications; however, their poor thermophysical properties require the use of heat transfer enhancement methods to provide a useful operating range. The microporous coating was developed specifically to enhance nucleate boiling performance in highly wetting fluids and to be benign enough for direct application to sensitive electronic chips. The microporous coating is a mixture of small particles (1- to 20-μm-diameter) and epoxy binder that creates a thin (≈50-μm thick), porous structure that contains re-entrant cavities. It is a surface treatment used to increase vapor/gas entrapment volume and active nucleation site density by forming a porous structure with cavities much smaller than conventional metallic porous coatings. Coating development improves incipience using re-entrant cavities and to enhance nucleate boiling heat transfer and critical heat flux (CHF) by significantly increasing the number of active nucleation sites. Under flow boiling conditions, the enhanced heat transfer benefit of the microporous coating depends on the boiling regime. In the boiling-dominated, subcooled convective boiling regime, the coating enables widespread subcooled boiling, thus providing significant heat transfer enhancements. The chapter discusses the development, optimization, and performance of the microporous coating and also highlights the physics behind the enhancement provided by the microporous coating.

Low-Noise Pulsed Pre-Polarization Magnet Systems for Ultra-Low Field NMR

A liquid cooled, pulsed electromagnet of solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system has been designed, fabricated and successfully operated. The magnet design minimizes Johnson noise, minimizes the hydrogen signal and incorporates minimal metal and no ferromagnetic materials. In addition, an acoustically quiet cooling system permitting 50% duty cycle operation was achieved by designing for single-phase, laminar flow, forced convection cooling. Winding, conductor splicing and epoxy impregnation techniques were successfully developed to produce a coil winding body with integral cooling passageways and adequate structural integrity. Issues of material compatibility, housing, coolant flow system and heat rejection system design will be discussed. Additionally, this pulsed electromagnet design has been extended to produce a boiling liquid cooled version in a paired solenoid configuration suitable for duty in an ultra-low field nuclear magnetic resonance system. This pair of liquid nitrogen cooled coils is currently being tested and commissioned. Issues of material compatibility, thermal insulation, thermal contraction, housing and coolant flow design are discussed.

Experimental Characterization and Predictive Modeling of a Residential-Scale Wind Turbine

As the demand for wind energy increases, industry and policymakers have been pushing to place larger wind turbines in denser wind farms. Furthermore, there are higher expectations for reliability of turbines, which require a better understanding of the complex interaction between wind turbines and the fluid flow that drives them. As a test platform, we used the Whisper 500 residential scale wind turbine to support structural and atmospheric modeling efforts undertaken to improve understanding of these interactions. The wind turbine’s flexible components (blades, tower, etc.) were modeled using finite elements, and modal tests of these components were conducted to provide data for experimental validation of the computational models. Finally, experimental data were collected from the wind turbine under real-world operating conditions. The FAST (Fatigue, Aerodynamics, Structures, and Turbulence) software developed at the National Renewable Energy Laboratory was used to predict total system performance in terms of wind input to power output along with other experimentally measurable parameters such as blade tip and tower top accelerations. This paper summarizes the laboratory and field test experiments and concludes with a discussion of the models’ predictive capability. LA-UR-12-24832.