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U.S. Department of Energy
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Steady-state cooling of a high-temperature superconducting motor

Conference ·
OSTI ID:7172787
; ; ; ;  [1]; ; ;  [2]
  1. Sandia National Labs., Albuquerque, NM (United States)
  2. Reliance Electric Co., Cleveland, OH (United States)

Development of a high-temperature, superconducting, synchronous motor for large applications (>1000 hp) could offer significant electrical power savings for industrial users. Presently 60% of all electric power generated in the United States is utilized by electric motors. A large part of this power is utilized by motors 1000 hp or larger. The use of high-temperature superconducting materials with critical temperatures above that of liquid nitrogen (77 K) in the field winding would reduce the losses in these motors significantly, and therefore, would have a definite impact on the electrical power usage in the US. These motors will be 1/3 to 1/2 the size of conventional motors of similar power and, thus, offer potential savings in materials and floor space. The cooling of the superconducting materials in the field windings of the rotor presents a unique application of cryogenic engineering. The rotational velocity results in significant radial pressure gradients that affect the flow distribution of the cryogen. The internal pressure fields can result in significant nonuniformities in the two-phase flow of the coolant. A multiphase flow computer model of the cryogenic cooling is developed to calculate the boiling heat transfer and phase distribution of the nitrogen coolant in the motor. The model accounts for unequal phase velocities and nonuniform cooling requirements of the rotor. Model results indicate a factor of 10 difference in the flow through axial coolant channels as a function of radius. The effect of this flow distribution needs to be accounted for in the design of the motor. Continuing improvements on the model will allow the investigation of the transient thermal issues associated with localized quenching of the superconducting components of the motor.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
DOE; EPRI; USDOE, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
7172787
Report Number(s):
SAND-92-0216C; CONF-921110--4; ON: DE92012624
Country of Publication:
United States
Language:
English