Flow field and heat transfer analysis of local structure for regenerative cooling panel

2012 ◽  
Vol 21 (2) ◽  
pp. 172-178 ◽  
Author(s):  
Yu Feng ◽  
Hongyan Huang ◽  
Tao Li ◽  
Duo Zhang ◽  
Zhongqi Wang
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Local Structure ◽  
Heat Transfer Analysis ◽  
Regenerative Cooling

FLOW FIELD AND HEAT TRANSFER ANALYSIS IN AMON/MMH BIPROPELLANT ROCKET ENGINE

2017 ◽  
Vol 16 (3) ◽  
pp. 263-280 ◽  
Author(s):  
Yu Daimon ◽  
Hideyo Negishi ◽  
Hiroumi Tani ◽  
Yoshiki Matsuura ◽  
Shigeyasu Iihara ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Rocket Engine ◽  
Heat Transfer Analysis

Computational Investigation of Flow and Heat Transfer Characteristics of Impingement Cooling Channel

2013 ◽  
Author(s):  
B. V. N. Ramakumar ◽  
D. S. Joshi ◽  
Murari Sridhar ◽  
Jong S. Liu ◽  
Daniel C. Crites
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Heat Transfer Analysis ◽  
Computational Investigation ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Impingement Cooling ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
High Heat Transfer

Impingement cooling offers very high heat transfer coefficients. Flow field, involved in impingement cooling is dominated by stagnation zone, transition zone and developing zone. Understanding of complex flow phenomenon and its effects on heat transfer characteristics is useful for efficient designing of impingement channels. Computational fluid dynamics (CFD) has emerged as a powerful tool for the analysis of flow and heat transfer systems. Honeywell has been investigating the use of CFD to determine the characteristics of various complex turbine blade cooling heat transfer augmentation methods such as impingement. The objective of this study is to develop CFD methodology which is suitable for computational investigation of flow and heat transfer analysis of impingement cooling through validation. Single row of circular jets impinging on concave (curved) surface has been considered for this study. The validation was accomplished with the test results of Bunker and Metzger [10] and with the correlations of Chupp et al. [7]. The parameters which are varied in this study include jet Reynolds number (Re2B = 6750–10200), target plate distance to jet diameter ratio (Z/d = 3 and 4), and target surface sharpness (i.e. radius ratio, r* = 0.2, 0.4 and 1) the simulations are performed under steady state conditions. Predicted results are compared for local endwall heat transfer results along the curve length of the mid span target wall. Flow field results obtained at different locations are presented to understand the heat transfer behavior.

An Analytical Model of External Streaming and Heat Transfer for a Levitated Flattened Liquid Drop

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Sungho Lee ◽  
S. S. Sadhal ◽  
Alexei Ye. Rednikov
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Acoustic Field ◽  
Thermophysical Properties ◽  
Liquid Drop ◽  
Thermocapillary Flow ◽  
Heat Transfer Analysis ◽  
Thermal Stimulus ◽  
Steady Streaming ◽  
Stokes Layer

We present here the heat-transfer and fluid flow analysis of an acoustically levitated flattened disk-shaped liquid drop. The interest in this work arises from the noncontact measurement of the thermophysical properties of liquids. Such techniques have application to liquids in the undercooled state, i.e., the situation when a liquid stays in a fluidic state even when the temperature falls below the normal freezing point. This can happen when, for example, a liquid sample is held in a levitated state. Since such states are easily disrupted by measurement probes, noncontact methods are needed. We have employed a technique involving the use of acoustically levitated samples of the liquid. A thermal stimulus in the form of laser heating causes thermocapillary motion with flow characteristics depending on the thermophysical properties of the liquid. In a gravity field, buoyancy is disruptive to this thermocapillary flow, masking it with the dominant natural convection. As one approach to minimizing the effects of buoyancy, the drop was flattened (by intense acoustic pressure) in the form of a horizontal disk, about 0.5mm thick. As a result, with very little gravitational potential, and with most of the buoyant flow suppressed, thermocapillary flow remained the dominant form of fluid motion within the drop. This flow field is visualizable and subsequent analysis for the inverse problem of the thermal property can be conducted. This calls for numerical calculations involving a heat-transfer model for the flattened drop. With the presence of an acoustic field, the heat-transfer analysis requires information about the corresponding Biot number. In the presence of a high-frequency acoustic field, the steady streaming originates in a thin shear-wave layer, known as the Stokes layer, at a surface of the drop. The streaming develops into the main fluid, and is referred to as the outer streaming. Since the Stokes layer is asymptotically thin in comparison to the length scale of the problem, the outer streaming can be formally described by an effective slip velocity at the boundary. The presence of the thin Stokes layer, and the slip condition at the interface, changes the character of the heat-transfer mechanism, which is inherently different from the traditional boundary layer. The current analysis consists of a detailed semianalytical calculation of the flow field and the heat-transfer characteristics of a levitated drop in the presence of an acoustic field.

Flow and Heat Transfer Analysis Through a Brake Disc: A CFD Approach

2006 ◽  
Author(s):  
S. Manohar Reddy ◽  
J. M. Mallikarjuna ◽  
V. Ganesan
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Heat Dissipation ◽  
Tangential Velocity ◽  
Heat Transfer Analysis ◽  
Brake Disc ◽  
Independence Test ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Grid Independence

This paper describes the numerical simulation of the flow and heat transfer around a ventilated brake disc. The aim of this investigation is to provide more insight on ventilated brake disc flow phenomena with a view to improve heat dissipation. Analysis of brake disc has been carried out using FLUENT (CFD code based on the Finite Volume Method). Numerical predictions of the flow and heat transfer are compared with available experimental data in the literature [2]. In the present work validation of numerical results are discussed in two parts. In the first part, the optimum grid was found from the grid independence test and in the second part the effect of turbulence models on flow field development was studied. Three rotors have been considered with each of 36, 40 and 45 number of vanes. Each rotor of two flow passages has been considered for the analysis. An isothermal analysis has been carried out to analyse the heat transfer. From the grid independence test it was found that the grid with 300,000 cells is seems to be the appropriate. SST k-ω turbulence model was able to predict the flow field with an accuracy of 3% and 1% in predicting tangential velocity and radial velocity respectively. From the isothermal rotor analysis it is found that the geometry having 45 vanes dissipates 7.7% and 5% more heat compared to geometries having number of vanes 36 and 40 respectively.

An Analytical Model of External Streaming and Heat Transfer for a Levitated Flattened Liquid Drop

2007 ◽  
Author(s):  
Sungho Lee ◽  
S. S. Sadhal ◽  
Alexei Ye. Rednikov
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Acoustic Field ◽  
Thermophysical Properties ◽  
Liquid Drop ◽  
Thermocapillary Flow ◽  
Heat Transfer Analysis ◽  
Thermal Stimulus ◽  
Steady Streaming ◽  
Stokes Layer

We present here the heat transfer and fluid flow analysis of an acoustically levitated flattened disk-shaped liquid drop. This work arises due to an interest in the non-contact measurement of the thermophysical properties of liquids. Such techniques have application to liquids in the undercooled state, i.e., the situation when a liquid stays in a fluidic state even when the temperature falls below the normal freezing point. This can happen when, for example, a liquid sample is held in a levitated state. Since such states are easily disrupted by measurement probes, non-contact methods are needed. We have employed a technique involving the use of acoustically levitated samples of the liquid. A thermal stimulus in the form of laser-heating causes thermocapillary motion with flow characteristics depending on the thermophysical properties of the liquid. In a gravity field, buoyancy is disruptive to this thermocapillary flow, masking it with the dominant natural convection. As one approach to minimizing the effects of buoyancy, the drop was flattened (by intense acoustic pressure) in the form of a horizontal disk, about 0.5 mm thick. As a result, with very little gravitational potential, with most of the buoyant flow suppressed, thermocapillary flow remained the dominant form of fluid motion within the drop. This flow field is visualizable and subsequent analysis for the inverse problem of the thermal property can be conducted. This calls for numerical calculations involving a heat transfer model for the flattened drop. With the presence of an acoustic field, the heat-transfer analysis requires information about the corresponding Biot number. In the presence of a high-frequency acoustic field, the steady streaming originates in a thin shear-wave layer, known as the Stokes layer, at a surface of the drop. The streaming develops into the main fluid, and is referred to as the outer streaming. Since the Stokes layer is asymptotically thin in comparison to the length scale of the problem, the outer streaming formally appears to be caused by an effective slip velocity at the boundary. The presence of the thin Stokes layer, and the slip condition at the interface, changes the character of the heat transfer mechanism which is inherently different from the traditional boundary layer. The current analysis consists of a detailed semi-analytical calculation of the flow field and the heat transfer characteristics of a levitated drop in the presence of an acoustic field.

Heat Transfer Analysis of a Wedge Shaped Duct With Pin Fin and Pedestal Arrays: A Comparison Between Numerical and Experimental Results

2004 ◽  
Author(s):  
Antonio Andreini ◽  
Carlo Carcasci ◽  
Andrea Magi
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Experimental Results ◽  
Heat Transfer Analysis ◽  
Bottom Surface ◽  
Mean Flow ◽  
Trailing Edge ◽  
Pin Fin

The use of pin fin arrays in channels is one of the best choices to enhance overall heat transfer in gas turbine trailing edge blade cooling. Furthermore, in this particular application, the use of cross-pins in the trailing edge section of a turbine blade is a good way for supplying structural integrity to the blade itself. In this paper, results of several 3D RANS calculations performed in channels with cross-pins disposition such as in a typical trailing edge of a gas turbine blade are shown. Numerical calculations were compared with experimental results obtained on the same geometries using a transient Thermochromic Liquid Crystals (TLC) based technique. Goals of this comparison are both the evaluation of the accuracy of CFD packages with standard two equation turbulence models in heat transfer problems with complex geometries and the analysis of flow details to complete and support experimental activity. Two computational domains have been considered: they both consist in a wedge shaped channel with a stream-wise normal pin fin or pedestal arrays. The aim of the numerical analysis is the evaluation of convective Heat Transfer Coefficient (HTC) on the planar bottom surface of the wedge-shaped duct: this surface is commonly named “endwall” surface. Detailed analysis of the flow field points out the coexistence of an horse-shoe vortex, a stagnant wake behind the pin and a mean flow acceleration due to convergent shape of the channel. Calculations reveal the presence of a weak jet-like flow field toward endwall surfaces caused by the strong recirculation behind each pin.

Analytical Approach for Finding Velocity and Temperature Distribution of Electroosmotic Flow in Micro- and Transitional Nano-Channels

2009 ◽  
Author(s):  
Saeid Movahed ◽  
Reza Kamali ◽  
Mohammad Eghtesad
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Flow Field ◽  
Channel Flow ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Heat Transfer Analysis ◽  
Heating Effect ◽  
Joule Heating Effect ◽  
Miniaturized Devices

The past decade has seen tremendous growth in areas of micro- and nano-fluidics, and MEMs flow control. Nowadays, there is considerable interest in micro- and nano/technologies consisting of small structures in contact with liquid media. By increasing the motivations of using miniaturized devices such as MEMS and NEMS and inventing new methods of their manufacturing, the inspirations of their study and analysis have been increased more and more. One of the most important characteristics of these devices which have undeniable impacts on their performances is miniaturized-channel flow field. By decreasing the dimensions of channels, the influence of surface effects becomes prominent and cannot be ignored. One of the most charismatic categories of these phenomena is elecrokinetic effect which can results in electroosmotic flow field (EOF) that has many advantages such as being vibration free, being much more compact, having flat-form velocity and etc. These beneficiaries lead to the increasing stimulus of using this type of flow field. One of the most important disadvantages of EOF is the Joule heating effect, the generation of heat due to the electroosmosis effect. Besides, miniaturized-channels are usually used as heat sink in miniaturized devices. By considering these facts, it can be concluded that heat characteristics of EOF must be studied carefully in order to manage the Joule heating effect and to utilize the cooling characteristics of miniaturized-channels. By reviewing the studies that have been performed in this field of study, it can be concluded that there is not any analytical approaches in dealing with heat transfer of EOF in miniaturized-channels though analytical formulas are completely essential for investigating, monitoring and controlling of any systems. In this regards, having some analytical studies on heat transfer analysis of miniaturized-channel flow field is completely essential. In the present study, by using the Schwartz-Christoffel mapping, an analytical tactic will be proposed in order to find electroosmotic velocity and consequently temperature distribution of EOF in micro- and transitional nano-channels.

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