CHINESE JOURNAL OF MECHANICAL ENGINEERING ·645·
if the length of pipe is shorter and ωnl/a is smaller, the natural frequency of system is
volume in this critical line is equal to 1, namely, Al/V=1。 The dimensionless volume is an important parameter used for discriminating between internal condensation and
external condensation。 Al/V≥1, only internal condensation
could occur; Al/V<1, only external condensation could occur。
The natural frequency n effects the motion performance
5 Conclusions
of system directly,
too。
is a comprehensive parameter
(1) The dimensionless volume of discharging pipe is proposed as the first parameter to discriminate occurrence
4。3 Analysis of interior condensation and exterior
condensation using dimensionless volume
Using the dimensionless volume of discharging pipe
of internal condensation or external condensation in a pneumatic system。 If the value of dimensionless volume is
larger than or equal to 1, the internal condensation occurs in
and A/V as comprehensive parameter of
system possibly, and no external condensation occurs;
condensation, we could analyze the distribution of all the
experimental points at which internal condensation and external condensation creates, and the analyzing results revealed the distribution of experimental points at which condensation or no condensation occurs in a certain regular rule as shown in Fig。 4, in which A/V is abscissa axis
oppositely, If the value of dimensionless volume is smaller than 1, the external condensation occurs in system possibly, and no internal condensation occurs。
(2) Condensation is defined that interior condensation
occurs in smaller volume cylinder and exterior condensation occurs in larger volume cylinder。 The
andis ordinate axis。
problem of piding line for cylinder volume exists in this definition。 Instead of the volume of cylinder, the dimensionless volume can be directly used to determine whether internal condensation or external condensation occurs in system, which provides an effective quantitative definition method for internal condensation or external condensation。 Meanwhile, the authors provide a possibility of evaluation and discrimination of condensation by using comprehensive parameter in experimental study。
(3) The study on condensation in pneumatic system involves many problems, such as the whole process of internal condensation including status of compressed air changes during charging and discharging, the water droplets producing and growing, the water droplets keeping in the system and the internal condensation occurring, or heat transfer taking place between the air and surface of
Fig。 4。 Distribution of experimental points at which internal condensation or external condensation occurs
The following can be noted by observing Fig。 4:
(1) The structural parameters of system in which internal condensation or external condensation meet a certain distribution。 In the area of upper left, external condensation occurs, and that of the lower right, internal condensation occurs。 气动系统中的冷凝英文文献和中文翻译(6):http://www.youerw.com/fanyi/lunwen_81820.html