共查询到17条相似文献,搜索用时 93 毫秒
1.
1.引言
在超声驻波的作用下,在除气水中可以实现单个气泡的超声悬浮,同时气泡也将会以驱动频率做膨胀塌缩运动,塌缩的剧烈程度随着声压的增加而变剧烈,当声压大到一定值时,在气泡的塌缩过程中就会发出光脉冲,这就是单泡声致发光(SBSL).既然SBSL是由于气泡的运动所产生的,那么研究气泡具体是如何运动的就变得十分重要,这将有助于了解声致发光的发光机理和过程.当然,影响声致发光的因素有很多,如声压、含气量、环境温度和压力、以及一些液体参数等等,其中激励声压是最根本的一个相关量.本文我们研究激励声压对气泡运动的影响. 相似文献
2.
3.
4.
5.
1引言
声致发光是一种将声能转化为光能的复杂的物理化学过程.大量在空间和时间都随机、不稳定的声致发光是多泡声致发光.而空间上固定,时间上具有周期性的是单泡声致发光.一直以来,只在多泡声致发光中发现了明显的谱线,所以认为多泡声致发光和单泡声致发光出于不同的机制.但是D.J.Flannigan和K.S.Suslick[1]以85%的浓硫酸为单泡声致发光的工作液体,观测到了明显的Ar原子谱线.根据原子发光理论可以很好地解释Ar原子谱线.本文试图对不同温度下Ne,Kr,Xe原子气泡的单泡声致发光特征谱线进行了理论计算,期待实验的验证. 相似文献
6.
7.
8.
0引言Gaitan等人在1992年首次实现了单个气泡的声致发光,即单泡声致发光[1](Single bubble sonoluminescence,缩写为SBSL)。而之前的气泡群声致发光现象称为多泡声致发光[2](Multi-bubble sonoluminescence,缩写为MBSL)。光谱测量一直是研究声致发光的有效手段之一。1995年,Matula等人[3]根据MBSL和SBSL的光谱,分析认为两者的区别是SBSL只有连续谱,而MBSL除了有连续 相似文献
9.
10.
11.
N. V. Dezhkunov 《Technical Physics Letters》2008,34(4):346-349
A phenomenological rule establishing a relationship between the cavitation threshold and the maximum intensity of sonoluminescence (SL) induced by ultrasound is formulated on the basis of experimental data for various liquid media. According to this, the maximum SL intensity attained by varying the intensity of ultrasound within broad limits is always greater in a medium characterized by a higher cavitation threshold. 相似文献
12.
A single bubble trapped at an antinode of an acoustic standing wave field in water can emit 50ps-140ps light pulses, called "single bubble sonoluminescence" (SBSL). It arouses much interest in physical acoustics because of its highly non-linear characteristics, high concentration of energy, and stable cavitation behavior. In this paper, bubble stability, the dynamic behavior of bubbles, non-invasive measurement of driving acoustic pressure and Mie scattering method are introduced. 相似文献
13.
Ayme-Bellegarda EJ Church CC 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1989,36(5):561-564
Calculations which are relevant to the determination of the maximum collapse pressure generated inside a microbubble as a function of peak pressure in the driving ultrasonic pulse are presented. It is found that above the threshold for transient cavitation, the maximum collapse pressure has a nonmonotonic variation. This result is explained on the basis of phase differences between the external applied acoustic pulse and the resulting bubble response. 相似文献
14.
I. M. Fedotkin S. M. Konstantinov A. A. Tereshchenko 《Journal of Engineering Physics and Thermophysics》1973,24(5):589-592
On the basis of the solution to the equation of motion of a variable mass, a formula is derived for analytically calculating the critical radius of a vapor bubble in a boiling liquid during free flow of the latter.Translated from Ihzhenerno-Fizicheskii Zhurnal, Vol. 24, No. 5, pp. 831–835, May, 1973. 相似文献
15.
Lubrication oil used in refrigerant compressors forms oil mist in the compressor shell. Some of the oil mist is discharged into a refrigeration cycle with refrigerant and causes degradation of heat transfer in heat exchangers. Since the generation of the oil mist is related to the Weber number, it is necessary to measure the surface tension of the oil/refrigerant mixture before discussing the oil mist generation in the compressor. In this study, the maximum bubble pressure method was adapted to measure the surface tension of PAG (polyalkylene glycol) oil/CO2 mixture. The density of the mixture needed for the measurement was also carried out. It was found that the surface tension of PAG/CO2 mixture sharply decreases with an increase in the concentration of the refrigerant in the mixture. The surface tension of the mixture under 10 MPa and 100 °C is estimated to be 14.6 mN m−1 by an extrapolation. 相似文献
16.
John Oliver 《Measurement Techniques》2000,43(2):195-196
Consultation
Relationship between pressure units 相似文献17.
It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of the hydraulic radius and the acoustic field which is characterized by the ratio of the traveling wave component over the standing wave component. In this paper, the normalized expressions of acoustic power gain and second law efficiency are derived and calculated, and then some useful calculated results are discussed. Some conclusions have been obtained, which are of significance to explain the optimum work conditions of existing engines and to guide the designs of new thermoacoustic devices. Finally, the operation factor of regenerator is discussed, which is a dimensionless parameter defined in this paper and highly relates to the working condition of the regenerator. 相似文献