A numerical investigation of nucleate boiling at a constant surface temperature

2015 ◽  
Vol 88 ◽  
pp. 248-257 ◽  
Author(s):  
H.W. Jia ◽  
P. Zhang ◽  
X. Fu ◽  
S.C. Jiang
Keyword(s):  
Surface Temperature ◽  
Numerical Investigation ◽  
Nucleate Boiling

scholarly journals Numerical investigation of nucleate boiling heat transfer on thin substrates

2014 ◽  
Vol 76 ◽  
pp. 45-64 ◽  
Author(s):  
A. Sanna ◽  
C. Hutter ◽  
D.B.R. Kenning ◽  
T.G. Karayiannis ◽  
K. Sefiane ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Nucleate Boiling Heat Transfer

Experimental Study on Behavior of Bubbles and Temperature Fluctuation of Heat Transfer Surface by Using Heat Transfer Surface With Artificial Cavities Created by MEMS Technology

2009 ◽  
Author(s):  
Takato Sato ◽  
Yasuo Koizumi ◽  
Hiroyasu Ohtake
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Correlation Coefficients ◽  
Side Surface ◽  
Nucleate Boiling ◽  
Heat Transfer Surface ◽  
Back Side ◽  
Mems Technology ◽  
Standard Deviations ◽  
Thermal Influence

Pool nucleate boiling heat transfer experiments were performed for water using heat transfer surfaces having a unified cavity. A single cylindrical hole of 10 μm in diameter and 40 μm in depth was formed on a mirror-finished silicon wafer of 0.2 mm in thickness using the Micro-Electro Mechanical Systems (MEMS) technology. This silicon plate was used as the heat transfer surface. The back side of the heat transfer surface was heated by a semi-conductor laser beam. The back-side surface temperature was measured by a radiation thermograph with a temperature resolution of 0.08 K and a time resolution of 3 ms/line. Experiments were conducted in the range up to 1.35 × 105 W/m2. The standard deviations of the local fluctuating heat transfer surface temperature were calculated. So the cross-correlation coefficients between the cavity center and a certain point were calculated by using the standard deviations and the time-series surface temperature data. Then, the intensity of the thermal influence exerted by the boiling bubbles on the local position was derived. The thermal influence extents determined from the intensity were 2.1 – 3.3 times larger than the mean diameter of all departure bubbles in the present experimental range.

A Compact Nanostructure Integrated Pool Boiler for Microscale Cooling Applications

2009 ◽  
Author(s):  
Muhsincan S¸es¸en ◽  
Cem Baha Akkartal ◽  
Wisam Khudhayer ◽  
Tansel Karabacak ◽  
Ali Kos¸ar
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
High Efficiency ◽  
Cooling System ◽  
Bubble Formation ◽  
Heat Removal ◽  
Nucleate Boiling ◽  
External Energy ◽  
Excessive Heat ◽  
Aluminum Base

An efficient cooling system consisting of a plate, on which copper nanorods (nanorods of size ∼100nm) are integrated to copper thin film (which is deposited on Silicon substrate), a heater, an Aluminum base, and a pool was developed. Heat is transferred with high efficiency to the liquid within the pool above the base through the plate by boiling heat transfer. Near the boiling temperature of the fluid, vapor bubbles started to form with the existence of wall superheat. Phase change took place near the nanostructured plate, where the bubbles emerged from. Bubble formation and bubble motion inside the pool created an effective heat transfer from the plate surface to the pool. Nucleate boiling took place on the surface of the nanostructured plate helping the heat removal from the system to the liquid above. The heat transfer from nanostructured plate was studied using the experimental setup. The temperatures were recorded from the readings of thermocouples, which were successfully integrated to the system. The surface temperature at boiling inception was 102.1°C without the nanostructured plate while the surface temperature was successfully decreased to near 100°C with the existence of the nanostructured plate. In this study, it was proved that this device could have the potential to be an extremely useful device for small and excessive heat generating devices such as MEMS or Micro-processors. This device does not require any external energy to assist heat removal which is a great advantage compared to its counterparts.

Numerical Study on Layout of Refractory Belt and Fouling Deposition in Tangentially Fired Boiler

2016 ◽  
Author(s):  
Qiongliang Zha ◽  
Kai Chen ◽  
Jianwen Zhang ◽  
Jiangtao Li ◽  
Chang’an Wang ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Numerical Investigation ◽  
Numerical Study ◽  
High Surface ◽  
Three Dimensional ◽  
Furnace Wall ◽  
Combustion Stability ◽  
Particle Capture ◽  
Dimensional Simulation ◽  
Ignition And Combustion

The refractory belt installed in primary combustion zone provides simplest and most effective solution to suppress ignition delay and enhance combustion stability for low volatile anthracite and lean coal. The fouling deposition generally formed on radiative refractory lined wall of the boiler due to a high surface temperature. The growth of deposition thickness is mainly dependent on the parcile impact on the surface of water wall. A particle capture submodel was used to determine whether a particle was captured to form deposition or not when it reached the furnace wall, and the particle capture criterion was based on the particle’s viscosity and the temperature of the furnace wall. A reduced fouling deposition model was implemented in a three dimensional simulation of a tangentially fired boiler. The numerical investigation was conducted to assess the performance of different layouts of refractory belt. Furnace temperature, surface temperature of refractory belt, and deposition distributions on the furnace wall should be taken into account when layouts of refractory belt are optimized. Based on this, three layouts of refractory belt were proposed for tangentially fired boilers. A numerical investigation was conducted to assess the performance of different layouts of refractory belt and the results showed that the temperature in furnace was increased, and the ignition and combustion processes were stabilized when refractory belts were installed. The reasonable arrangement of refractory belt could reduce the possibility of fouling deposition in furnace.

Visual Onset of Nucleate Boiling in Water Spray Cooling on Hot Steel Plate

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Jungho Lee ◽  
Sang Gun Lee ◽  
Jinsub Kim
Keyword(s):  
Temperature Gradient ◽  
Surface Temperature ◽  
Steel Plate ◽  
Outer Zone ◽  
Nucleate Boiling ◽  
Spray Cooling ◽  
Spray Nozzle ◽  
Water Spray ◽  
Nozzle Height ◽  
Water Spray Cooling

The onset of nucleate boiling in water spray cooling on hot steel plate was investigated by a simultaneous boiling visualization and heat transfer measurement. The boiling phenomena were visualized with 4K video camera and the surface temperature of the hot steel plate was determined by solving 2-D inverse heat conduction during water spray cooling. The temperature was measured by a sampling rate of 10 data/sec. The hot steel plate was initially heated up to 900°C and the coolant temperature was kept at a constant temperature of 20°C. The spray nozzle with fullcone pattern was mounted with the three different heights (100, 200 and 300 mm). The more spray height was increased, the more scattered the spray pattern became, which could affect the partial spray intensity and overall cooling uniformity. The lower spray nozzle height of 100 mm shows the steep temperature gradient in inner zone. As the spray particles are more intense at inner zone which wets faster than outer zone. But the higher spray nozzle height of 300 mm, the temperature profile keeps constant within the 400 sec. After this time, the outer zone is wetted faster than inner zone. At the middle height of 200 mm, although the temperature gradient in inner zone is slightly higher than that in outer zone, the overall surface wetting is relatively uniform in the inner and outer zone. These results exhibit that the spray cooling uniformity can be controlled with optimized spray nozzle height. Furthermore the boiling visualization agrees well with the onset of nucleate boiling in surface temperature profiles.

Sign in / Sign up

Export Citation Format

Share Document