COMPUTER SIMULATION OF TRANSFER PROCESSES IN MICROJET BURNER DEVICES WITH SPECIAL COOLING SYSTEMS

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
Viktor Prokopov ◽  
Sergiy Alioshko ◽  
Julii Sherenkovskiy ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Cooling System ◽  
Cooling Systems ◽  
Transfer Processes ◽  
Flow And Heat Transfer ◽  
Inner Surface ◽  
Air Blowing

The analysis of efficiency of cooling system of the microjet stabilization burner devices is performed. The features of the flow and heat transfer in cooling systems with air blowing of the inner surface of flame stabilizator and with flat and circular impact jets are studied.

scholarly journals Investigation of Thermo-Flow Characteristics of Natural Draft Dry Cooling Systems Designed with Only One Tower in 2 × 660 MW Power Plants

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1308
Author(s):  
Mohan Liu ◽  
Lei Chen ◽  
Kaijun Jiang ◽  
Xiaohui Zhou ◽  
Zongyang Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Cooling System ◽  
Flow Characteristics ◽  
Cooling Systems ◽  
Natural Draft ◽  
Wind Speeds ◽  
Flow And Heat Transfer ◽  
Power Load ◽  
Dry Cooling

In recent years, natural draft dry cooling systems with only one tower have been adopted in some 2 × 660 MW power-generating units owing to the advantage of lower construction costs. The operating cases of two power-generating units and one power-generating unit will both appear based on the power load requirement, which may lead to very different flow and heat transfer performances of this typical cooling system. Therefore, this research explores the local thermo-flow characteristics of air-cooled heat exchangers and sectors, and then analyzes the overall cooling performance of the above two operating cases under various wind conditions. Using the numerical modeling method, the results indicate that the flow and heat transfer performance of this cooling system decreases significantly in the case of one unit with half sectors dismissed. At wind speeds lower than 8 m/s, the difference in turbine back pressure between two units and one unit appears obviously higher than in other wind conditions, even reaching 4.37 kPa. Furthermore, the air-cooled heat exchanger in the lower layer always has better cooling capability than that in the upper layer, especially in conditions where there is an absence of wind and under low wind speeds. The operating case of one unit is not recommended for this dry cooling system because of the highly decreased energy efficiency. In conclusion, this research could provide theoretical support for the engineering operation of this typical natural draft dry cooling system in 2 × 660 MW power plants.

Flow and Heat Transfer in a Rotating Cavity With a Stationary Stepped Casing

2000 ◽  
Author(s):  
Abdul A. Jaafar ◽  
Fariborz Motallebi ◽  
Michael Wilson ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Laser Doppler Anemometry ◽  
Tangential Component ◽  
Rotating Disc ◽  
Turbine Engine ◽  
Flow And Heat Transfer ◽  
Rotating Cavity ◽  
Rotating Discs ◽  
Cooling Air

In this paper, new experimental results are presented for the flow in a co-rotating disc system with a rotating inner cylinder and a stationary stepped outer casing. The configuration is based on a turbine disc-cooling system used in a gas turbine engine. One of the rotating discs can be heated, and cooling air is introduced through discrete holes angled inward at the periphery of this disc. The cooling air leaves the system through axial clearances between the discs and the outer casing. Some features of computed flows, and both measured and computed heat transfer, were reported previously for this system. New velocity measurements, obtained using Laser Doppler Anemometry, are compared with results from axisymmetric, steady, turbulent flow computations obtained using a low-Reynolds-number k-ε turbulence model. The measurements and computations show that the tangential component of velocity is invariant with axial location in much of the cavity, and the data suggest that Rankine (combined free and forced) vortex flow occurs. The computations fail to reproduce this behaviour, and there are differences between measured and computed details of secondary flow recirculations. Possible reasons for these discrepancies, and their importance for the prediction of associated heat transfer, are discussed.

Computation of flow and heat transfer through channels with periodic dimple/protrusion walls using low-Reynolds number turbulence models

2019 ◽  
Vol 29 (3) ◽  
pp. 1178-1207 ◽  
Author(s):  
Mohammad Fazli ◽  
Mehrdad Raisee
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Correction Term ◽  
Turbine Blades ◽  
Turbulence Models ◽  
Internal Cooling ◽  
Recirculation Bubble ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Numerical Predictions

PurposeThis paper aims to predict turbulent flow and heat transfer through different channels with periodic dimple/protrusion walls. More specifically, the performance of various low-Rek-ε turbulence models in prediction of local heat transfer coefficient is evaluated.Design/methodology/approachThree low-Re numberk-εturbulence models (the zonalk-ε, the lineark-εand the nonlineark-ε) are used. Computations are performed for three geometries, namely, a channel with a single dimpled wall, a channel with double dimpled walls and a channel with a single dimple/protrusion wall. The predictions are obtained using an in house finite volume code.FindingsThe numerical predictions indicate that the nonlineark-εmodel predicts a larger recirculation bubble inside the dimple with stronger impingement and upwash flow than the zonal and lineark-εmodels. The heat transfer results show that the zonalk-εmodel returns weak thermal predictions in all test cases in comparison to other turbulence models. Use of the lineark-εmodel leads to improvement in heat transfer predictions inside the dimples and their back rim. However, the most accurate thermal predictions are obtained via the nonlineark-εmodel. As expected, the replacement of the algebraic length-scale correction term with the differential version improves the heat transfer predictions of both linear and nonlineark-εmodels.Originality/valueThe most reliable turbulence model of the current study (i.e. nonlineark-εmodel) may be used for design and optimization of various thermal systems using dimples for heat transfer enhancement (e.g. heat exchangers and internal cooling system of gas turbine blades).

scholarly journals Special Issue “Fluid Flow and Heat Transfer”

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3044
Author(s):  
Artur J. Jaworski
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Special Issue ◽  
Science And Engineering ◽  
Planetary Scale ◽  
Transfer Processes ◽  
Flow And Heat Transfer

Fluid flow and heat transfer processes play an important role in many areas of science and engineering from the planetary scale (e [...]

CFD Modeling of the Multiphase Flow and Heat Transfer for Piston Gallery Cooling System

2007 ◽  
Author(s):  
Yong Yi ◽  
Madhusudhana Reddy ◽  
Mark Jarrett ◽  
Pin Shyu ◽  
Cletus Kinsey ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Multiphase Flow ◽  
Cooling System ◽  
Cfd Modeling ◽  
Flow And Heat Transfer
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