Magnetic Resonance Thermometry Experimental Setup: A Portable Heat Transfer Experiment

Author(s):  
Elliott T. Williams ◽  
Jonathan R. Spirnak ◽  
Marc C. Samland ◽  
Brant G. Tremont ◽  
Alfred L. McQuirter ◽  
...  

This work provides a detailed description of the setup and execution of an experiment employing Magnetic Resonance Thermometry (MRT) techniques for measuring the three-dimensional temperature field of a fully turbulent jet mixing with a cross flow. The proposed methodology has the flexibility of applying different thermal boundary conditions — adiabatic and conductive — by varying the materials used in the test section as well as varying the temperatures of the mixing flows. The experiment described in this paper employs a standard magnetic resonance imaging system comparable to those used in medical radiology departments worldwide. A series of MR scans with both isothermal and thermal mixing conditions were conducted and results are presented with sub-millimeter resolution across the measured 3D domain of interest within one degree Celsius. The methodology presented here holds unique advantages over conventional techniques because measurements can be acquired without introducing flow disturbances and in regions without any optical access. When coupled with other established MR-based measurement techniques, MRT provides large, robust data sets that can be used for validation, design, and insight into system thermal performance for complex, turbulent flows. The materials and components employed in this work cost approximately $13,900, and the experimental setup and data collection required approximately 48 hours.

Author(s):  
Michael J. Benson ◽  
Bret P. Van Poppel ◽  
Christopher J. Elkins ◽  
Mark Owkes

Magnetic Resonance Thermometry (MRT) is a maturing diagnostic used to measure three-dimensional temperature fields. It has great potential for investigating fluid flows within complex geometries leveraging medical grade MRI equipment and software along with novel measurement techniques. The efficacy of the method in engineering applications increases when coupled with other well established MRI-based techniques such as Magnetic Resonance Velocimetry (MRV). In this study, a challenging geometry is presented with direct application to a complex gas turbine blade cooling scheme. Turbulent external flow with a Reynolds number of 136,000 passes a hollowed NACA-0012 airfoil with internal cooling features. Inserts within the airfoil, fed by a second flow line with an average temperature difference of 30 K from the main flow and a temperature-dependent Reynolds number in excess of 1,800, produce a conjugate heat transfer scenario including impingement cooling on the inside surface of the airfoil. The airfoil cooling scheme also includes zonal recirculation, surface film cooling, and trailing edge ejection features. The entire airfoil surface is constructed of a stereolithography resin — Accura 60 — with low thermal conductivity. The three-dimensional internal and external velocity field is measured using MRV. The fluid temperature field is measured within and outside of the airfoil with MRT and the results are compared with a computational fluid dynamics (CFD) solution to assess the current state of the art for combined MRV/MRT techniques for investigating these complex internal and external flows. The accompanying CFD analysis provides a prediction of the velocity and temperature fields, allowing for errors in the MRT technique to be estimated.


2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Michael J. Benson ◽  
Bret P. Van Poppel ◽  
Christopher J. Elkins ◽  
Mark Owkes

Magnetic resonance thermometry (MRT) is a maturing diagnostic tool used to measure three-dimensional temperature fields. It has a great potential for investigating fluid flows within complex geometries leveraging medical grade magnetic resonance imaging (MRI) equipment and software along with novel measurement techniques. The efficacy of the method in engineering applications increases when coupled with other well-established MRI-based techniques such as magnetic resonance velocimetry (MRV). In this study, a challenging geometry is presented with the direct application to a complex gas turbine blade cooling scheme. Turbulent external flow with a Reynolds number of 136,000 passes a hollowed NACA-0012 airfoil with internal cooling features. Inserts within the airfoil, fed by a second flow line with an average temperature difference of 30 K from the main flow and a temperature-dependent Reynolds number in excess of 1,800, produces a conjugate heat transfer scenario including impingement cooling on the inside surface of the airfoil. The airfoil cooling scheme also includes zonal recirculation, surface film cooling, and trailing edge ejection features. The entire airfoil surface is constructed of a stereolithography resin—Accura 60—with low thermal conductivity. The three-dimensional internal and external velocity field is measured using an MRV. The fluid temperature field is measured within and outside of the airfoil with an MRT, and the results are compared with a computational fluid dynamics (CFD) solution to assess the current state of the art for combined MRV/MRT techniques for investigating these complex internal and external flows. The accompanying CFD analysis provides a prediction of the velocity and temperature fields, allowing for errors in the MRT technique to be estimated.


1995 ◽  
Vol 13 (6) ◽  
pp. VI-VII
Author(s):  
Machida Yoshio ◽  
Hatanaka Masahiko ◽  
Kitane Shinichi

1987 ◽  
Vol 21 (2) ◽  
pp. 204-207 ◽  
Author(s):  
Hidehiko Nabatame ◽  
Hidenao Fukuyama ◽  
Ichiro Akiguchi ◽  
Masakuni Kameyama ◽  
Kazumasa Nishimura ◽  
...  

2016 ◽  
Vol 16 (6) ◽  
pp. 294-299 ◽  
Author(s):  
S. Solis-Najera ◽  
F. Vazquez ◽  
R. Hernandez ◽  
O. Marrufo ◽  
A.O. Rodriguez

Abstract A surface radio frequency coil was developed for small animal image acquisition in a pre-clinical magnetic resonance imaging system at 7 T. A flexible coil composed of two circular loops was developed to closely cover the object to be imaged. Electromagnetic numerical simulations were performed to evaluate its performance before the coil construction. An analytical expression of the mutual inductance for the two circular loops as a function of the separation between them was derived and used to validate the simulations. The RF coil is composed of two circular loops with a 5 cm external diameter and was tuned to 300 MHz and 50 Ohms matched. The angle between the loops was varied and the Q factor was obtained from the S11 simulations for each angle. B1 homogeneity was also evaluated using the electromagnetic simulations. The coil prototype was designed and built considering the numerical simulation results. To show the feasibility of the coil and its performance, saline-solution phantom images were acquired. A correlation of the simulations and imaging experimental results was conducted showing a concordance of 0.88 for the B1 field. The best coil performance was obtained at the 90° aperture angle. A more realistic phantom was also built using a formaldehyde-fixed rat phantom for ex vivo imaging experiments. All images showed a good image quality revealing clearly defined anatomical details of an ex vivo rat.


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