Transient boiling and pressure recovery in a vacuum vessel during cooling of a high temperature body with an impinging jet
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
|Research Institution||Saga University|
MONDE Masanori Saga Univ., Dept.of Mech.Eng.Professor, 理工学部, 教授 (80109222)
MITSUTAKE Yuichi Saga Univ., Dept.of Mech.Eng.Assistant Professor, 理工学部, 助手 (20253586)
MOHAMMED Has 佐賀大学, 理工学部, 助教授 (40274576)
HASAN Mohammed Saga Univ., Dept.of Mech.Eng.Associate Professor
|Project Period (FY)
1997 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥2,800,000 (Direct Cost : ¥2,800,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥2,200,000 (Direct Cost : ¥2,200,000)
|Keywords||Transient boiling / Quenching / Impinging jet cooling / Pressure recovery / 非定常沸騰|
An experimental study has been made on transient heat transfer during cooling of a high temperature (300ﾟC) cylindrical body mounted in a vacuum vessel with an impinging jet and then recovery of pressure in the vessel. The experiment was carried out for initial pressure of 500 to 1000 Pa, jet velocity of 1 to 15 m/s, jet diameter of 1 to 3 mm, and jet temperature of 10 to 90ﾟC using water as test liquid. Copper, brass and steel are used as test material in order to check effect of different thermal properties on the transient cooling. The following results are obtained :
1. Characteristics of pressure recovery and heat transfer are categorized in to three regions as
Region A : The pressure recovery is dominated by flush evaporation of superheated liquid. This region finishes at a short time. The heat transfer rate from high temperature body is limited resulting into little evaporation of liquid of jet.
Region B : The pressure recovery is influenced by amount of vapor generated by boiling
on high temperature disk. Boiling area moves toward outer edge of disk surface with time.
Region C : The pressure recovers to a corresponding state and is kept constant during which heat transfer from the surface becomes forced convective, only.
2. The pressure recovery and heat transfer rate are strongly influenced by test material since the time at which wetting of the high temperature surface starts depends on thermal properties. The heat transfer rate from the surface would be controlled by thermal properties of material.
3. A computation procedure is developed to estimate surface heat flux from transient temperature during cooling, although a time lag exist between surface and measuring points and then is not predicted accurate.
4. A relationship between movement of boiling area and heat transfer rate is made clear, although a time lag between them exists.
5. A model to predict pressure recovery from heat transfer rate during cooling is developed, showing that the value predicted is in good agreement with experimental one. Less
Research Output (18results)