【摘要】 建立双源超声铝合金铸造熔池模型,利用fluent软件模拟相同频率与不同频率下相位差对熔池声场的影响。仿真结果显示,相同频率下,相位差显著影响熔池声场的分布,随相位差增大,熔池空化域变小;不同频率下,相位差对熔池声场的分布无影响。通过不同相位差双源超声铸造试验发现,同频率振动下,相位差对双源超声铸造边部及超声辐射区的晶粒细化效果影响很小,心部晶粒细化效果随相位差变大效果变差;不同振动频率作用下,相位差对铸锭细晶效果无影响,心部晶粒细化效果与同频率相位差为90?时接近。同频率相位差0?超声作用下,铸锭心部晶粒尺寸较常规不同频率双源超声作用下心部晶粒尺寸大幅减小。更多还原

【Abstract】 The model of aluminum alloy dual-source ultrasonic casting bath was established, and the effects of different phase-differences on the bath sound field under the same and different frequencies were simulated with fluent software. The results of simulation show that under the same frequency, the distribution of sound field is significantly affected by phase-differences, and the cavitation domain decreases with increasing phase-difference; while phase-differences have no effect on the sound field distribution under difference frequencies. The dual-source casting conducted with different phase-differences under the same frequency shows little effects on the refinement of grains in the edge and ultrasound irradiation fields, and the refinement of grains in the center part deteriorates with increasing phase-difference. While under the condition of different frequencies, the phase-differences show no effect on the refinement of grains, and the refinement of grains in the center part is similar to that under the conditions of dual-source ultrasound with the same frequency and a phase-difference of 90?. Under the conditions of dual-source ultrasound with the same frequency and a phase-difference of 0?, the grain size decreases much compared to that conducted with dual-source ultrasound with different frequencies.更多还原