Analysis of single phase flow pressure drop and heat transfer in a horizontal rifled tube

2012 ◽  
Author(s):  
Soo Poey Lam ◽  
Abas Abdul Wahab ◽  
Saparudin Ariffin ◽  
Lee Woon Kiow
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Single Phase ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Flow Pressure

scholarly journals Single phase flow pressure drop and heat transfer in rectangular metallic microchannels

2016 ◽  
Vol 93 ◽  
pp. 1324-1336 ◽  
Author(s):  
Amirah M. Sahar ◽  
Mehmed R. Özdemir ◽  
Ekhlas M. Fayyadh ◽  
Jan Wissink ◽  
Mohamed M. Mahmoud ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Single Phase ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Flow Pressure

Single-Phase Flow Characteristics and Effect of Dissolved Gases on Heat Transfer Near Saturation Conditions in Microchannels

2002 ◽  
Author(s):  
Satish G. Kandlikar ◽  
Mark E. Steinke ◽  
Prabhu Balasubramanian
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Surface Temperature ◽  
Friction Factor ◽  
Single Phase ◽  
Saturation Temperature ◽  
Slight Reduction ◽  
Phase Flow ◽  
Dissolved Gases ◽  
Single Phase Flow

An experimental investigation is carried out to study the heat transfer and pressure drop in the single-phase flow of water in a microchannel. The effect of dissolved gases on heat transfer and pressure drop is studied as the wall temperature approaches the saturation temperature of water, causing air and water vapor mixture to form bubbles on the heater surface. A set of six parallel microchannels, each approximately 200 micrometers square in cross section and fabricated in copper, with a hydraulic diameter of 207 micrometers, is used as the test section. Starting with air-saturated water at atmospheric pressure and temperature, the air content in the water is varied by vigorously boiling the water at elevated saturation pressures to provide different levels of dissolved air concentrations. The single-phase friction factor and heat transfer results are presented and compared with the available theoretical values. The friction factors for adiabatic cases match closely with the laminar single-phase friction factor predictions available for conventional-sized channels. The diabatic friction factor, after applying the correction for temperature dependent properties, also agrees well with the theoretical predictions. The Nusselt numbers, after applying the property corrections, are found to be below the theoretical values available in literature for constant temperature heating on all four sides. The disagreement is believed to be due to the three-sided heating employed in the current experiments. The effect of gas content on the heat transfer for the three gas concentrations is investigated. Nucleation was observed at a surface temperature of 90.5°C, for the reference case of 8.0 ppm. For the degassed cases (5.4 ppm and 1.8 ppm), nucleation is not observed until the surface temperature reached close to 100°C. An increase in heat transfer coefficient for surface temperatures above saturation is observed. However, a slight reduction in heat transfer is noted as the bubbles begin to nucleate. The presence of an attached bubble layer on the heating surface is believed to be responsible for this effect.

Thermofluid Characteristics of Two-Phase Microgap Coolers

2007 ◽  
Author(s):  
Dae W. Kim ◽  
Emil Rahim ◽  
Avram Bar-Cohen ◽  
Bongtae Han
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Boiling ◽  
Phase Flow ◽  
Dissolved Gas ◽  
Single Phase Flow ◽  
Two Phase ◽  
Phase Water

The thermofluid characteristics of a chip-scale microgap cooler, including single-phase flow of water and FC-72 and flow boiling of FC-72, are explored. Heat transfer and pressure drop results for single phase water are used to validate a detailed numerical model and, together with the convective FC-72 data, establish a baseline for microgap cooler performance. Experimental results for single phase water and FC-72 flowing in 120 μm, 260 μm and 600 μm microgap coolers, 31mm wide by 34mm long, at velocities of 0.1 – 2 m/s are reported. “Pseudo-boiling” driven by dissolved gas and flow boiling of FC-72 are found to provide significant enhancement in heat transfer relative to theoretical single phase values.

Thermal and Hydrodynamic Characteristics of Single-Phase Flow and Flow Boiling in a Staggered Micro-Pin-Fin Array

2008 ◽  
Author(s):  
Weilin Qu
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Single Phase ◽  
Flow Boiling ◽  
Hydrodynamic Characteristics ◽  
Inlet Temperature ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Pin Fin ◽  
Pin Fin Array

This study concerns thermal and hydrodynamic characteristics of water single-phase flow and flow boiling in a micro-pin-fin array. An array of 1950 staggered square micro-pin-fins with a 200×200 μm2 cross-section by a 670 μm height were fabricated into a copper heat sink test section. Two inlet temperatures of 30 °C and 60 °C, and six maximum mass velocities for each inlet temperature, ranging from 183 to 420 kg/m2s, were tested. The corresponding inlet Reynolds number ranged from 45.9 to 179.6. General characteristics of single-phase flow and flow boiling were described. Predictive tools were proposed for single-phase heat transfer coefficient and pressure drop. Unique features of flow boiling heat transfer in the micro-pin-fin array were identified. The classic Lockhart-Martinelli correlation incorporating a single-phase micro-pin-fin friction factor correlation and the laminar liquid–laminar vapor combination assumption was used to predict two-phase pressure drop in the micro-pin-fin array. The predictions agreed well with the experimental data.

Single Phase Flow Pressure Drop in Glass Ballotini Particulate Beds

2004 ◽  
Vol 22 (3-4) ◽  
pp. 381-396
Author(s):  
Sabah Yassin Ibrahim ◽  
Emad Talib Hashim
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Flow Pressure
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