Advanced Rayleigh Pressure Loss Model for High-Swirl Combustion in a Rotating Combustion Chamber

2015 ◽  
Author(s):  
Andreas Penkner ◽  
Peter Jeschke
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Dynamic Model ◽  
Gas Turbines ◽  
Total Pressure ◽  
Fluid Flows ◽  
Pressure Losses ◽  
Gas Dynamic ◽  
Swirl Combustion ◽  
Transfer Problems

This paper considers the effect of excessive total pressure losses for heat transfer problems in fluid flows with a high circumferential swirl component. At RWTH Aachen University, a novel gas generator concept is under research. This design avoids some disadvantages of small gas turbines and uses a rotating combustion chamber. During the pre-design of the rotating combustion chamber using CFD tools, unexpected high total pressure losses were detected. To analyze this unknown phenomenon, a gas-dynamic model of the rotating combustion chamber has been developed to explain the unexpected high Rayleigh pressure losses. The derivation of the gas-dynamic model, the physical phenomenon related to the high total pressure losses in high-swirl combustion, the influencing factors, as well as thermodynamic interpretation of the Rayleigh pressure losses, are presented in this paper. In addition, the CFD results are validated by the gas-dynamic model derived. The results presented here are of possible interest for a wide range of applications, since these fundamental findings can be transferred to all heat transfer problems in fluid flows with a high circumferential swirl component.

scholarly journals Internal Aerodynamics and Heat Transfer Problems Associated to Film Cooling of Gas Turbines

1979 ◽  
Author(s):  
Emile Le Grivès ◽  
J.-J. Nicolas ◽  
Jeanne Génot
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Flow Distribution ◽  
Transfer Coefficients ◽  
Pressure Losses ◽  
Effects Of Rotation ◽  
Transient Thermal ◽  
Turbine Airfoils ◽  
Transfer Problems

Heat transfer and aerodynamic processes within coolant ducts and film emission holes of high temperature gas turbine components have been investigated at ONERA by means of specially devised test rigs affording an adequate similitude of geometrical or aerothermal parameters. Results obtained in tests at steady or transient thermal regime are reported for several points of interest concerning internal coolant circuits: • Heat transfer through multihole parts of turbine airfoils • Aerodynamics of flows within perforated ducts, with special attention to coolant mass flow distribution, to pressure losses and heat transfer coefficients in small or scaled up turbine blade models • Heat transfer over a perforated wall, with mass transfer of the coolant flow through holes of various patterns and pitch-to-diameter ratio. Experimental data are discussed in regard to desired accuracy for the analysis of heat transfer in air-cooled gas turbines, except for the effects of rotation.

Pressure Losses for Jet Array Impingement With Crossflow

2012 ◽  
Author(s):  
Yeshayahou Levy ◽  
Arvind G. Rao ◽  
V. Erenburg ◽  
V. Sherbaum ◽  
I. Gaissinski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Numerical Simulations ◽  
Gas Turbines ◽  
Total Pressure ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Solar Panels ◽  
Cfd Simulations ◽  
Pressure Losses

Jet impingement is an efficient heat transfer method and has been used successfully in cooling of turbine blades in gas turbine engines. Although many studies have been conducted on the heat transfer characteristics of jet impingement array, there is a lack of knowledge in pressure drop characteristics of large jet impingement arrays. The pressure losses encountered are becoming increasingly important when applied to micro gas turbines, cooling concentrated solar panels and high density electronic chips. The present work focuses on experimental and theoretical investigation of pressure losses in low Re impingement arrays, 200< Re <3000. Experiments were carried out on jet impingement array with nozzle diameters of 200 to 800 μm. Numerical simulations were also performed with available commercial CFD tools. Reasonable comparisons between experimental results and numerical simulations were obtained. Detailed flow structure, mass flow rate distribution, jet velocity profiles, and pressure drop within the array in the streamwise direction were obtained from the CFD simulations. These simulations enhance the understanding of the physics within multiple jet impingement system. Additionally a semi empirical–analytical method is developed for calculating the total pressure loss within a multi jet impingement system. This simple methodology can provide a quick estimate of the total pressure drop and hence is suited for first order optimization. The methodology is validated by results obtained from experiments and from CFD simulations.

Effect of Divergence Angle on Flow Through Inlet Section of Diffuser of a Gas Turbine Combustion Chamber: The CFD Approach

2006 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jitendra Chaudhary ◽  
Zoeb Lakdawala ◽  
Hitesh Solanki ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Total Pressure ◽  
Divergence Angle ◽  
Velocity Head ◽  
Turbine Engine ◽  
Inlet Velocity ◽  
Pressure Losses ◽  
Flow Through ◽  
Mach Numbers

In the combustor inlet diffuser section of gas turbine engine, high-velocity air from compressor flows into the diffuser, where a considerable portion of the inlet velocity head PT3 − PS3 is converted to static pressure (PS) before the airflow enters the combustor. Modern high through-flow turbine engine compressors are highly loaded and usually have high inlet Mach numbers. With high compressor exit Mach numbers, the velocity head at the compressor exit station may be as high as 10% of the total pressure. The function of the diffuser is to recover a large proportion of this energy. Otherwise, the resulting higher total pressure loss would result in a significantly higher level of engine specific fuel consumption. The diffuser performance must also be sensitive to inlet velocity profiles and geometrical variations of the combustor relative to the location of the pre-diffuser exit flow path. Low diffuser pressure losses with high Mach numbers are more rapidly achieved with increasing length. However, diffuser length must be short to minimize engine length and weight. A good diffuser design should have a well considered balance between the confliction requirements for low pressure losses and short engine lengths. The present paper describes the effect of divergence angle on diffuser performance for gas turbine combustion chamber using Computational Fluid Dynamic Approach. The flow through the diffuser is numerically solved for divergence angles ranging from 5 to 25°. The flow separation and formation of wake regions are studied.

scholarly journals Selection of the Design of a Contact Condenser of a Gas-Steam Plant with Steam Injection into the Combustion Chamber

2021 ◽  
pp. 29-34
Author(s):  
Oksana Lytvynenko ◽  
Irina Myhaylova
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Gas Turbines ◽  
Packed Column ◽  
High Heat ◽  
Thermal Design ◽  
Gas Mixture ◽  
Design Calculation ◽  
Transfer Coefficients ◽  
High Heat Transfer

Due to the importance of the problems of implementing energy-saving technologies in modern conditions, one of the promising areas is the use of gas turbines for combined heat and power generation. One of the areas of effective development and technical re-equipment is the widespread use of highly economical combined steam and gas plants and gas turbines. The operation of the gas turbine unit “Aquarius” SE NPCG “Zorya-Mashproekt” with the injection of steam into the combustion chamber, which operates on the advanced cycle A-STIG and has in its circuit equipment for water regeneration, condensed from a vapor-gas mixture is considered. For condensation of steam from the vapor-gas mixture, a contact condenser-gas cooler is used, which is a mixing heat exchanger of complex design. The efficiency of heat transfer is determined by the design of the nozzle, namely, the developed heat transfer surface, small hydraulic supports, high heat transfer coefficients. An important aspect is the overall dimensions, which must be within certain limits. In the work it is offered to execute a design of the condenser in the form of a packed column. Different types of nozzles are considered to choose the best option. As a result of thermal design calculation of the contact capacitor, it is proposed to use Rashiga rings (15152) as a nozzle, which provide the lowest height of the nozzle at the required diameter of the device.

Design for Additive Manufacturing: Internal Channel Optimization

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
M. Pietropaoli ◽  
R. Ahlfeld ◽  
F. Montomoli ◽  
A. Ciani ◽  
M. D'Ercole
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Additive Manufacturing ◽  
Thermal Diffusivity ◽  
Gas Turbines ◽  
Steepest Descent Method ◽  
Optimization Approach ◽  
Pressure Losses ◽  
The Impact ◽  
Straight Duct

The new possibilities offered by additive manufacturing (AM) can be exploited in gas turbines to produce a new generation of complex and efficient internal coolant systems. The flexibility offered by this new manufacturing method needs a paradigm shift in the design approach, and a possible solution is offered by topology optimization. The overall goal of this work is to propose an innovative method to design internal channels in gas turbines that fully exploit AM capabilities. The present work contains a new application of a fluid topology sedimentation method to optimize the internal coolant geometries with minimal pressure losses while maximizing the heat exchange. The domain is considered as a porous medium with variable porosity: the solution is represented by the final solid distribution that constitutes the optimized structure. In this work, the governing equations for an incompressible flow in a porous medium are considered together with a conjugate heat transfer equation that includes porosity-dependent thermal diffusivity. An adjoint optimization approach with steepest descent method is used to build the optimization algorithm. The simulations are carried out on three different geometries: a U-bend, a straight duct, and a rectangular box. For the U-bend, a series of splitter is automatically generated by the code, minimizing the stagnation pressure losses. In the straight duct and in the rectangular box, the impact of different choices of the weights and of the definition of the porosity-dependent thermal diffusivity is analyzed. The results show the formation of splitters and bifurcations in the box and “riblike” structures in the straight duct, which enhance the heat transfer.

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