Heat Transfer and Film Dynamic in Shear-Driven Liquid Film Cooling System of Microelectronic Equipment

2004 ◽  
Author(s):  
O. A. Kabov ◽  
V. V. Kuznetsov ◽  
J. C. Legros
Keyword(s):  
Liquid Film ◽  
Gas Phase ◽  
Film Cooling ◽  
Gas Flow ◽  
Cooling System ◽  
Plane Channel ◽  
Wave Theory ◽  
Nitrogen Gas ◽  
Large Channel ◽  
Steady Laminar

The conjugated two-dimensional model, based on long-wave theory, of a steady laminar flow of liquid film and co-current gas flow in plane channel with the height varied from 150 to 500 μm is performed. A chip with the several millimeters length is located on the bottom wall of channel. The linearised approximation of the problem is obtained analytically. Numerical calculations are executed for liquid FC-72 and Nitrogen gas flow. In contrast to a case of a large channel, there is essential an influence of liquid film deformations on pressure and velocity in a gas phase.

Comparative study of high concentrating photovoltaics integrated with phase-change liquid film cooling system

2019 ◽  
Vol 43 (6) ◽  
pp. 2108-2122 ◽  
Author(s):  
Yiping Wang ◽  
Junpeng Huo ◽  
Liqun Zhou ◽  
Qunwu Huang
Keyword(s):  
Comparative Study ◽  
Liquid Film ◽  
Phase Change ◽  
Film Cooling ◽  
Cooling System

The Thermocapillary Convection in Locally Heated Laminar Liquid Film Flow Caused by a Co-Current Gas Flow in Narrow Channel

2003 ◽  
Author(s):  
E. Y. Gatapova ◽  
Y. V. Lyulin ◽  
I. V. Marchuk ◽  
O. A. Kabov ◽  
J.-C. Legros
Keyword(s):  
Free Surface ◽  
Analytical Solution ◽  
Liquid Film ◽  
Gas Flow ◽  
Surface Deformation ◽  
Plane Channel ◽  
Film Surface ◽  
Local Heat ◽  
Narrow Channel ◽  
Liquid Film Flow

A two-dimensional model of a steady laminar flow of liquid film and co-current gas flow in a plane channel is considered. It is supposed that the height of a channel is much less than its width. There is a local heat source on the bottom wall of the channel. An analytical solution for the temperature distribution problem in locally heated liquid film is obtained, when the velocity profile is linear. An analytical solution of the linearized equation for thermocapillary film surface deformation is found. A liquid bump caused by the thermocapillary effect in the region where thermal boundary layer reaches the film surface is obtained. Damped oscillations of the free surface may exist before the bump. This is obtained according to the solution of the problem in an inclined channel. It depends on the forces balance in the film. The defining criterion is found for this effect. The oscillations of free surface do not exist for horizontally located channel.

Nonthermal Microwave Plasma Synthesis of Crystalline Titanium Oxide & Titanium Nitride Nanoparticles

1991 ◽  
Vol 249 ◽  
Author(s):  
Prabhjot Mehta ◽  
A. K. Singh ◽  
A. I. Kingon
Keyword(s):  
Titanium Nitride ◽  
Gas Phase ◽  
Titanium Oxide ◽  
Gas Flow ◽  
Microwave Plasma ◽  
Molecular Nitrogen ◽  
Plasma Synthesis ◽  
Titanium Tetraisopropoxide ◽  
Low Oxygen ◽  
Nitrogen Gas

ABSTRACTWe report the nonthermal synthesis of ultrafine crystalline nanoparticles of titanium oxide and titanium nitride. The nanoparticles are formed by gas phase reactions between precursor gases dissociated in the microwave plasma. For the production of titanium nitride, titanium tetraisopropoxide (TTIP) and ammonia or nitrogen precursor gases are used. For titanium oxide production TTIP and oxygen are used as precursor gases. In both cases ultrahigh purity argon serves as a carrier gas and diluent.Transmission electron microscopy (TEM) revealed that the titanium nitride powders so formed were either cubic (TiN) or tetragonal (Ti2N) depending on the operational conditions, particularly the relative nitrogen gas flow rates. Ammonia gas was found to be a much more reactive nitrogen source than molecular nitrogen gas. For the titanium oxide growth an excess of oxygen was utilized to achieve TiO2. Powders collected from the gas phase corresponded to the rutile (tetragonal) phase. However, powders collected from the cavity walls corresponded to the high temperature and pressure (orthorhombic) 13-TiO2. There was also evidence of a polytypically modulated phase of TiO2, with the observed c-periodicity double the parent c-periodicity of the rutile phase. Using a low oxygen flow rate during powder formation led to the formation of orthorhombic Ti3O5 “powders”. The powders were easily sinterable by in situ electron beam annealing in the electron microscope, with an estimated temperature of around 550°C. This is much lower than the temperatures normally required to sinter these materials.

Experimental and Numerical Study of the Thermal Performance of a Film Cooled Turbine Platform

2009 ◽  
Author(s):  
D. Charbonnier ◽  
P. Ott ◽  
M. Jonsson ◽  
F. Cottier ◽  
Th. Ko¨bke
Keyword(s):  
Thermal Performance ◽  
Film Cooling ◽  
Gas Flow ◽  
Cooling System ◽  
Numerical Study ◽  
Guide Vane ◽  
Density Ratio ◽  
Secondary Flows ◽  
Test Case ◽  
Film Cooling Effectiveness

Detailed surface measurements of the thermal performance of a film cooling system have been performed on the endwall of a nozzle guide vane (NGV) mounted in a linear cascade facility at EPFL. An external cooling scheme including several rows of fan-shaped and cylindrical cooling holes has been designed. By testing different cooling flow rates at a NGV exit Reynolds number of 1.7E+06 and Mach number of 0.88, detailed aerodynamic and heat transfer values were obtained destined to assess the design tools for film cooled platforms. The surface static pressure distribution and the film cooling effectiveness on the endwall surface have been experimentally determined. The measurements were obtained applying the pressure sensitive paint technique measuring the coolant gas concentration. An engine representative density ratio between the coolant and the external hot gas flow was achieved by the injection of CO2. The working conditions of the test case similar to realistic engine conditions allow for the validation of in-house CFD codes and the investigation of the reliability of modern commercial tools in such a complex cooling system. The numerical campaign has been performed on the same numerical grid, using the commercial codes FLUENT and CFX, used by EPFL and MTU respectively. A detailed analysis of the grid effects on the obtained results has been previously realised as well as the study of the influence of the modelling approximations. Three cooling mass flows have been simulated and the performance parameters of the film cooling system have been compared to the experimentally obtained data. Special emphasis has been put on the jet penetration effects and on the interaction of secondary flows with the coolant flow. The experimental and numerical efforts were part of the EU funded research project TATEF2 (Turbine Aero-Thermal External Flows 2).

A conduction-cooled stage for high-resolution Cryo-SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1282-1283
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Liquid Nitrogen ◽  
Mechanical Stability ◽  
Cooling System ◽  
Cold Trap ◽  
Nitrogen Gas ◽  
Particulate Suspensions ◽  
Advantages And Disadvantages ◽  
Convection Cooling ◽  
Styrene Butadiene

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

Numerical simulation of swirling flow effect on the first stage vane film cooling distribution

2016 ◽  
Vol 07 (03) ◽  
pp. 1650031
Author(s):  
Hong Yin
Keyword(s):  
Flow Field ◽  
Film Cooling ◽  
Swirling Flow ◽  
Cooling System ◽  
Leading Edge ◽  
Suction Side ◽  
Local Area ◽  
Swirl Flow ◽  
Flow Effect ◽  
Recirculation Flow

In advanced gas turbine technology, lean premixed combustion is an effective strategy to reduce peak temperature and thus, NO[Formula: see text] emissions. The swirler is adopted to establish recirculation flow zone, enhancing mixing and stabilizing the flame. Therefore, the swirling flow is dominant in the combustor flow field and has impact on the vane. This paper mainly investigates the swirling flow effect on the turbine first stage vane cooling system by conducting a group of numerical simulations. Firstly, the numerical methods of turbulence modeling using RANS and LES are compared. The computational model of one single swirl flow field is considered. Both the RANS and LES results give reasonable recirculation zone shape. When comparing the velocity distribution, the RANS results generally match the experimental data but fail to at some local area. The LES modeling gives better results and more detailed unsteady flow field. In the second step, the RANS modeling is incorporated to investigate the vane film cooling performance under the swirling inflow boundary condition. According to the numerical results, the leading edge film cooling is largely altered by the swirling flow, especially for the swirl core-leading edge aligned case. Compared to the pressure side, the suction side film cooling is more sensitive to the swirling flow. Locally, the film cooling jet is lifted and turned by the strong swirling flow.

Effect of impingement jet on the full-coverage film cooling system with double layered wall

2017 ◽  
Vol 30 (6) ◽  
pp. 544-562 ◽  
Author(s):  
Eui Yeop Jung ◽  
Sang Hyun Oh ◽  
Dong Hyun Lee ◽  
Kyung Min Kim ◽  
Hyung Hee Cho
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Impingement Jet ◽  
Full Coverage

Combined Experimental and CFD Study of a HP Blade Multi-Pass Cooling System

2009 ◽  
Author(s):  
D. Jackson ◽  
P. Ireland ◽  
B. Cheong
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Cooling System ◽  
Detailed Comparison ◽  
Bulk Temperature ◽  
Internal Cooling ◽  
3 Dimensional ◽  
Turbine Cooling ◽  
Cooling Hole ◽  
The Difference

Progress in the computing power available for CFD predictions now means that full geometry, 3 dimensional predictions are now routinely used in internal cooling system design. This paper reports recent work at Rolls-Royce which has compared the flow and htc predictions in a modern HP turbine cooling system to experiments. The triple pass cooling system includes film cooling vents and inclined ribs. The high resolution heat transfer experiments show that different cooling performance features are predicted with different levels of fidelity by the CFD. The research also revealed the sensitivity of the prediction to accurate modelling of the film cooling hole discharge coefficients and a detailed comparison of the authors’ computer predictions to data available in the literature is reported. Mixed bulk temperature is frequently used in the determination of heat transfer coefficient from experimental data. The current CFD data is used to compare the mixed bulk temperature to the duct centreline temperature. The latter is measured experimentally and the effect of the difference between mixed bulk and centreline temperature is considered in detail.

Comparative Study of GaN Growth Process by MOVPE

1999 ◽  
Vol 572 ◽  
Author(s):  
Jingxi Sun ◽  
J. M. Redwing ◽  
T. F. Kuech
Keyword(s):  
High Temperature ◽  
Comparative Study ◽  
Gas Phase ◽  
Residence Time ◽  
Gas Flow ◽  
Flow Sheet ◽  
Flow Zone ◽  
High Quality ◽  
Phase Temperature ◽  
High Temperature Gas

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.

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