Yuan Hongyong

Research on Early Fire Smoke Movements and Detection Method in Stable Thermally Stratified Environments

The movements of smoldering cotton wick smoke and flaming diesel oil smoke plumes in thermally stratified environments in a small scale enclosure were investigated by experiments and CFD simulations. The reasonably good agreements of the experimental and simulated results indicated that the thermally stratified environments intensified the decreases of the axial temperatures and velocities of a fire smoke plume. The previous integral equation was shown to underestimate the maximum smoke rises, and also unable to explain the differences of the maximum heights of low and high density smoke with the same stratification and outlet conditions. An improved integral equation and an effective detection method were introduced and discussed.

A Study of the Vibration of the Charging Belt in an Electrostatic Accelerator

The vibration of the charging belt in an electrostatic accelerator has intense influences on the accelerator operation. A calculating model was set up in this paper to study the belt vibration. The results show that the belt tension, belt velocity and belt current all contribute to the belt vibration. There is an optimal relationship among the three factors by which the belt would run most smoothly. There exists a minimum value of optimal tension for various belt velocities. The vibrating frequency of the is generally around several Hz.

Study on the Focusing Properties of the Accelerating Tube

An accelerating tube is an electrostatic lens system. This paper made use of the micro unit model to derive the path equations of an accelerating tube by integrating the ion path of a unit electrostatic lens. The focusing properties are discussed according to the calculated results.

Characteristics of a R.F. Ion Source Used in an Electrostatic Accelerator

A radio frequency (r.f.) ion source used in the electrostatic accelerator was designed and built for the study on the ion beam bioengineering. The extracting characteristics were determined by experiments, from which the results showed that a maximal beam current is obtained under the condition of the extracting voltage 1700V and the gas pressure in the range of (4–8) × 10-4 Pa. And the diameter of the ion beam was measured as well.