309 The Flow Pattern in Working Process of Oscillating Capillary Tube Heat Pipe (OCHP)

2007 ◽  
Vol 2007.43 (0) ◽  
pp. 77-78
Author(s):  
Akira HOSHI ◽  
Tatsuro YONEKURA
Keyword(s):  
Heat Pipe ◽  
Flow Pattern ◽  
Capillary Tube ◽  
Working Process

Theoretical Realizability of Dream-Pipe-Like Oscillating/Pulsating Heat Pipe

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Masao Furukawa
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Capillary Tube ◽  
Feasibility Studies ◽  
Temperature Fields ◽  
Pulsating Heat Pipe ◽  
Long Distance ◽  
Effective Thermal Diffusivity ◽  
Energy Equations ◽  
Adiabatic Section

The state of the art of thermally self-excited oscillatory heat pipe technology is briefly mentioned to emphasize that there exists no oscillating/pulsating heat pipe (OHP/PHP) suited to long-distance heat transport. Responding to such conditions, this study actively proposes a newly devised conceptually novel type of OHP/PHP. In that heat pipe, the adiabatic section works as it were the dream pipe invented by Kurzweg. This striking quality of the proposed new-style OHP/PHP produces high possibilities of long-distance heat transport. To support such optimistic views, an originally planned mathematical model is introduced for feasibility studies. Hydraulic considerations have first been done to understand what conditions are required for sustaining bubble-train flows in a capillary tube of interest. Theoretical analysis has then been made to solve the momentum and energy equations governing the flow velocity and temperature fields in the adiabatic section. The obtained analytical solutions are arranged to give algebraic expressions of the effective thermal diffusivity, the performance index combined with the tidal displacement, and the required electric power. Computed results of those three are displayed in the figures to demonstrate the realizability of that novel OHP.

scholarly journals Flow Pattern and Pressure Drop Characteristics on Gas/Liquid Two-phase Flow in a Serpentine Capillary Tube

2007 ◽  
Vol 2 ◽  
pp. 25-32 ◽  
Author(s):  
Toru SUKAWA ◽  
Tomoya HASEGAWA ◽  
Kenji YOSHIDA ◽  
Isao KATAOKA
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Capillary Tube ◽  
Phase Flow ◽  
Two Phase

Multi-Fields Coupled Simulation on Casting Process of Aluminum Alloy Based on Heat Conduction by Rotating Heat Pipe Bundle

2012 ◽  
Vol 621 ◽  
pp. 237-245
Author(s):  
Jian Mei Chen ◽  
Yu Qiang Li ◽  
Jia Qiang E
Keyword(s):  
Aluminum Alloy ◽  
Heat Conduction ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Casting Process ◽  
Working Process ◽  
New Approach ◽  
Molten Liquid ◽  
Ingot Solidification ◽  
Structure Layout

Based on the knowledge to defects and advantages of traditional ingot casting, a new approach for casting of aluminum alloy ingot, based on heat conduction by rotating heat pipes, is put forward in this paper. Different from the conventional casting method that cooling around ingot, the microstructure and properties of casting ingots can be significantly improved due to cooling of molten liquid from the central by rotating heat pipes proposed by this paper. Through simulation on the working process and the fields of flow and temperature, it can be speculatively seen that the ingot solidification is from inside to outside and that inner stress inside the ingot is compressive. The influences of speed of heat pipe bundle, casting speed and casting temperature on the temperature field in the ingot have been systematically studied. The ingots with different sizes can be prepared by changing size and structure layout of the heat pipes.

Flow Pattern and Condensation Mechanism in a Condenser of Loop Heat Pipe

2019 ◽  
Vol 2019 (0) ◽  
pp. 0102
Author(s):  
Noriyuki Watanabe ◽  
Masayuki Yamamoto ◽  
Shoji Uryu ◽  
Hosei Nagano
Keyword(s):  
Heat Pipe ◽  
Flow Pattern ◽  
Loop Heat Pipe

Visualization of an Oscillating Heat Pipe with Hydraulic Diameter Far Exceeding the Conventional Maximum Hydraulic Diameter

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Yulong Ji ◽  
Lilin Chu ◽  
Chunrong Yu ◽  
Zongyu Wang ◽  
Hongbin Ma
Keyword(s):  
Heat Pipe ◽  
Flow Pattern ◽  
Bubbly Flow ◽  
Research Work ◽  
Filling Ratio ◽  
Hydraulic Diameter ◽  
Working Fluid ◽  
Oscillating Heat Pipe ◽  
Fundamental Research ◽  
Small Bubbles

Abstract For an oscillating heat pipe (OHP), the hydraulic diameter must be sufficiently small so that vapor plug and liquid slug can be formed by the capillary action. Therefore, the hydraulic diameter should not exceed a critical value named maximum hydraulic diameter (MHD). In the current research, a glass OHP with a hydraulic diameter of 6 mm was fabricated, and ethanol was used as the working fluid (Figs. 1 and 2). With a hydraulic diameter far exceeding the maximum hydraulic diameter (MHD) defined by dh,max≤{2σBo[(ρl−ρv)g]}1/2, the OHP can function. But the flow pattern is very different from that with a diameter smaller than the MHD, and depends on the filling ratio. When the OHP is charged with a higher filling ratio, the flow pattern is from the bubbly flow to the slug flow as shown in Fig, 3. When the charging ratio is low, the dispersed bubbly flow with many small bubbles generated on the surface was observed, and the dispersed bubbly flow was directly transformed into the annular flow as shown in Fig. 4. [This research work was supported by National Natural Science Foundation of China under Grant No. 51876019, the Preresearch of General Armament Department (6140922011310), LiaoNing Revitalization Talents Program (XLYC1807117), and the Fundamental Research Funds for the Central Universities of China under Grant No.3132019331.]

Flow visualization of oscillation characteristics of liquid and vapor flow in the oscillating capillary tube heat pipe

2003 ◽  
Vol 17 (10) ◽  
pp. 1507-1519 ◽  
Author(s):  
Jong-Soo Kim ◽  
Ngoc Hung Bui ◽  
Ju-Won Kim ◽  
Jeong-Hoon Kim ◽  
Hyun Seok Jung
Keyword(s):  
Flow Visualization ◽  
Heat Pipe ◽  
Capillary Tube ◽  
Vapor Flow ◽  
Oscillation Characteristics

scholarly journals A Dynamic Film Model of the Pulsating Heat Pipe

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Vadim S. Nikolayev
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Capillary Tube ◽  
Numerical Code ◽  
Oscillating Flow ◽  
Pulsating Heat Pipe ◽  
Two Phase ◽  
Thermally Induced ◽  
Film Evaporation ◽  
Condensation Model

This article deals with the numerical modeling of the pulsating heat pipe (PHP) and is based on the film evaporation/condensation model recently applied to the single-bubble PHP (Das et al., 2010, “Thermally Induced Two-Phase Oscillating Flow Inside a Capillary Tube,” Int. J. Heat Mass Transfer, 53(19–20), pp. 3905–3913). The described numerical code can treat the PHP of an arbitrary number of bubbles and branches. Several phenomena that occur inside the PHP are taken into account: coalescence of liquid plugs, film junction or rupture, etc. The model reproduces some of the experimentally observed regimes of functioning of the PHP such as chaotic or intermittent oscillations of large amplitudes. Some results on the PHP heat transfer are discussed.

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