Electrohydrodynamically Enhanced Convective Boiling of Alternative Refrigerants: Fundamental Understanding and Applicability
摘要:
Electrohydrodynamically (EHD) enhanced convective boiling, based on the extraction phenomenon, is experimentally investigated. The working fluids are R-134a and R404A refrigerants. Both smooth and enhanced tubes are investigated in a horizontal configuration. The heat transfer enhancement and suppression with the corresponding pressure-drop data are presented. The ratio of EHD power consumption relative to the heat transferred was less than 1.5% for the data presented A theoretical analysis is presented to determine the contributing terms of the EHD power consumption, and it was determined that the electric conduction mechanism was the primary contributing factor to current flow. The transient application of EHD, in the case that resulted in the suppression of the heat transfer under steady-state conditions, provided transient enhancements for convective boiling of R-404A in a horizontal smooth tube. Additional, applicability of the EHD extraction phenomenon to convective boiling is discussed.
Background: Avulsion fractures of the anterior superior iliac spine are uncommon injuries. Most of them occur in adolescent athletes. Traditionally, they have been treated conservatively. We describe operative treatment of avulsion fractures that might shorten the period of rehabilitation. Methods and results: Six patients with avulsion fractures of the anterior superior iliac spine were treated operatively by open reduction and osteosynthesis with two Kirschner wires and a wire loop. After 6 weeks, all of them had resumed their sports activities. No complications were recorded. Conclusions: Operative treatment of anterior superior iliac spine avulsions may reduce the time to full recovery. It should be considered for athletes requiring a short period of rehabilitation.