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Kiruba Haran

Publications and source records attributed to Kiruba Haran.

3 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2026

Center for High-Efficiency Electrical Technologies for Aircraft: Phase I Final Report

Under the University Leadership Initiative (ULI), the Center for High-Efficiency for Electrical Technologies (CHEETA) was established to develop and mature early-stage technologies pertaining to hydrogen-electric power and energy systems for aircraft. In particular, integration of these technologies on an aircraft system is envisioned to leverage the high specific energy content of liquid hydrogen (LH2) with fuel cell energy conversion and an electrically driven ducted fan system to provide an ultra-efficient propulsion drivetrain. For this concept, the LH2 system is not just used as an energy storage mechanism, but also as a cryogen to enable highly efficient superconducting electric systems. The end result of this concept is an integrated aircraft system with a quiet, efficient propulsion architecture that produces zero CO2, NOx, SOx, and particulate matter emissions at the vehicle level.

Hydrogen↗
NASA NTRSDate not supplied

Electromagnetic Redesign of NASA’s High Efficiency Megawatt Motor

NASA’s High Efficiency Megawatt Motor (HEMM) is being developed to achieve the performance needed by single aisle class electrified aircraft. It is a 1.4 MW electric machine designed as a generator for NASA’s STARC-ABL concept vehicle. It has performance objectives of greater than 16 kW/kg electromagnetic specific power and efficiency of greater than 98%. A significant flaw in the preliminary electromagnetic design of HEMM was recently discovered. The stator teeth in the preliminary design cause the magnetic flux in the rotating components of HEMM to oscillate at a very high frequency (12,240 Hz). Two independent energy loss analyses are presented to show that the frequency is high enough to cause eddy current losses that significantly exceed the rotor’s loss limit (50 W), despite the very small magnitude of this flux oscillation (<0.01 T). To eliminate these rotor losses, while continuing to meet the target performance, it was determined that the stator teeth needed to be removed and the electromagnetic geometry of the motor needed to be revised. The revised, slotless HEMM motor design is summarized. Sensitivity of the new design to key unknown variables such as the temperature of and number of turns in the superconducting rotor coils and the stator winding’s average temperature.

Thomas T Tallerico↗