Effects of Effusion and Film Cooling Jet Momenta on Combustor Flow Fields

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Alejandro M. Briones ◽  
Scott D. Stouffer ◽  
Konstantinos Vogiatzis ◽  
Keith Rein ◽  
Brent A. Rankin
Keyword(s):  
Mass Flow ◽  
Film Cooling ◽  
A Priori ◽  
Three Dimensional ◽  
Flow Fields ◽  
Ex Situ ◽  
Reacting Flow ◽  
Flow Measurements ◽  
Flow Rates ◽  
Flamelet Generated Manifold

The effects of effusion and film cooling momenta on combustor flow fields are investigated. Steady, compressible three-dimensional (3D) simulations are performed on a single-swirler combustor using Reynolds-averaged Navier–Stokes (RANS) with flamelet generated manifold and Lagrangian–Eulerian multiphase spray, while accounting for dome and liner cooling. Two simulations are performed on the same mesh. One simulation is conducted using a parallelized, automated, predictive, imprint cooling (PAPRICO) model with dynamic flux boundary conditions and downstream pressure probing (DFBC-DPP). PAPRICO involves removing the cooling jet geometry from the dome and liner while retaining the cooling hole imprints. The PAPRICO model does not require a priori knowledge of the cooling flow rates through various combustor liner regions nor specific mesh partitioning. The other simulation is conducted using the homogenously patched cooling (HPC) model, which involves removing all the cooling jets. The HPC model applies volumetric sources adjacent to the combustor wall regions where cooling jets are present. The momentum source, however, becomes negligible. The HPC model is not predictive and requires tedious ex situ mass flow measurements from an auxiliary flowbench experiment, afflicted with systematic errors. Hence, the actual in situ air flow splits through the several combustor regions is not known with absolute certainty. The numerical results are compared with measurements of mass flow rates, static pressure drops, and path-integrated temperatures. The results demonstrate that it is critical to account for the discrete dome and liner cooling momentum to better emulate the reacting flow in a combustor.

End-Wall Film Cooling Through Fan-Shaped Holes With Different Area Ratios

2006 ◽  
Vol 129 (2) ◽  
pp. 212-220 ◽  
Author(s):  
Giovanna Barigozzi ◽  
Giuseppe Franchini ◽  
Antonio Perdichizzi
Keyword(s):  
Secondary Flow ◽  
Mass Flow ◽  
Film Cooling ◽  
Three Dimensional ◽  
Wide Band ◽  
Lateral Spreading ◽  
Area Ratio ◽  
Adiabatic Effectiveness ◽  
Flow Effects ◽  
End Wall

The present paper reports on the aerothermal performance of a nozzle vane cascade, with film-cooled end walls. The coolant is injected through four rows of cylindrical holes with conical expanded exits. Two end-wall geometries with different area ratios have been compared. Tests have been carried out at low speed (M=0.2), with coolant to mainstream mass flow ratio varied in the range 0.5–2.5%. Secondary flow assessment has been performed through three-dimensional (3D) aerodynamic measurements, by means of a miniaturized five-hole probe. Adiabatic effectiveness distributions have been determined by using the wide-band thermochromic liquid crystals technique. For both configurations and for all the blowing conditions, the coolant share among the four rows has been determined. The aerothermal performances of the cooled vane have been analyzed on the basis of secondary flow effects and laterally averaged effectiveness distributions; this analysis was carried out for different coolant mass flow ratios. It was found that the smaller area ratio provides better results in terms of 3D losses and secondary flow effects; the reason is that the higher momentum of the coolant flow is going to better reduce the secondary flow development. The increase of the fan-shaped hole area ratio gives rise to a better coolant lateral spreading, but appreciable improvements of the adiabatic effectiveness were detected only in some regions and for large injection rates.

An Accurate Performance Prediction of Solid Fuel Ramjets Using Coupled Intake-Combustor-Nozzle Simulation

2020 ◽  
Vol 36 (6) ◽  
pp. 933-941
Author(s):  
A. M. Tahsini
Keyword(s):  
Combustion Chamber ◽  
Solid Fuel ◽  
Solid Phase ◽  
Three Dimensional ◽  
Flow Fields ◽  
Reacting Flow ◽  
Computational Domain ◽  
Regression Rate ◽  
Fuel Flow ◽  
Accurate Performance

ABSTRACTThe performance of the solid fuel ramjet is accurately predicted using full part simulation of this propulsion system, where the flow fields of the intake, combustion chamber, and the nozzle are numerically studied all together. The conjugate heat transfer is considered between the solid phase and the gas phase to directly compute the regression rate of the fuel. The finite volume solver of the compressible turbulent reacting flow is utilized to study the axisymmetric three dimensional flow fields, and two blocks are used to discretize the computational domain. It is shown that the combustion chamber's pressure is changed due to the fuel flow rate's increment which must be taken into account in predictions. The results demonstrate that omitting the pressure dependence of the regression rate and also the effect of the combustor's inlet profile on the regression rate, which specially exists when simulating the combustion chamber individually, under-predicts the solid fuel burning rate when the regression rate augmentation technique is applied to improve the performance of the solid fuel ramjets. It is also illustrated that using the inlet swirl to increase the regression rate of the solid fuel augments considerably the thrust level of the considered SFRJ, while the predictions without considering all parts of the ramjet is not accurate.

Analysis of the Mixing Plane Interface Between Stator and Rotor of a Transonic Axial Turbine Stage

2000 ◽  
Author(s):  
P. Giangiacomo ◽  
V. Michelassi ◽  
F. Martelli
Keyword(s):  
Mass Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Turbine Stage ◽  
Flow Rates ◽  
Tip Leakage ◽  
Mass Flow Rates ◽  
Stator Blade ◽  
Transonic Turbine ◽  
Rotor Mass

A three-dimensional transonic turbine stage is computed by means of a numerical simulation tool. The simulation accounts for the coolant ejection from the stator blade and for the tip leakage of the rotor blade. The stator and rotor rows interact via a mixing plane, which allows the stage to be computed in a steady manner. The analysis is focused on the matching of the stator and rotor mass flow rates. The computations proved that the mixing plane approach allows the stator and rotor mass flow rates to be balanced with a careful choice of the stator-rotor static pressure interface. At the same time, the pitch averaged distribution of the transported quantities at the interface for the stator and rotor may differ slightly, together with the value of the static pressure at the hub.

Identification of Wake Convection and Flow Outline in the Interface Region of Blade Rows With Axial Gap in a Counter Rotating Turbine

2019 ◽  
Author(s):  
Rayapati Subbarao ◽  
M. Govardhan
Keyword(s):  
Flow Pattern ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Three Dimensional ◽  
Interface Region ◽  
Turbine Stage ◽  
Deviation Angle ◽  
Flow Rates ◽  
Improved Performance

Abstract In a Counter Rotating Turbine (CRT), the stationary nozzle is trailed by two rotors that rotate in the opposite direction to each other. Flow in a CRT stage is multifaceted and more three dimensional, especially, in the gap between nozzle and rotor 1 as well as rotor 1 and rotor 2. By varying this gap between the blade rows, the flow and wake pattern can be changed favorably and may lead to improved performance. Present work analyzes the aspect of change in flow field through the interface, especially the wake pattern and deviation in flow with change in spacing. The components of turbine stage are modeled for different gaps between the components using ANSYS® ICEM CFD 14.0. Normalized flow rates ranging from 0.091 to 0.137 are used. The 15, 30, 50 and 70% of the average axial chords are taken as axial gaps in the present analysis. CFX 14.0 is used for simulation. At nozzle inlet, stagnation pressure boundary condition is used. At the turbine stage or rotor 2 outlet, mass flow rate is specified. Pressure distribution contours at the outlets of the blade rows describe the flow pattern clearly in the interface region. Wake strength at nozzle outlet is more for the lowest gap. At rotor 1 outlet, it is less for x/a = 0.3 and increases with gap. Incidence angles at the inlets of rotors are less for the smaller gaps. Deviation angle at the outlet of rotor 1 is also considered, as rotor 1-rotor 2 interaction is more significant in CRT. Deviation angle at rotor 1 outlet is minimum for this gap. Also, for the intermediate mass flow rate of 0.108, x/a = 0.3 is giving more stage performance. This suggests that at certain axial gap, there is better wake convection and flow outline, when compared to other gap cases. Further, it is identified that for the axial gap of x/a = 0.3 and the mean mass flow rate of 0.108, the performance of CRT is maximum. It is clear that the flow pattern at the interface is changing the incidence and deviation with change in axial gap and flow rate. This study is useful for the gas turbine community to identify the flow rates and gaps at which any CRT stage would perform better.

scholarly journals Leading Edge Film Cooling Effects on Turbine Blade Heat Transfer

1995 ◽  
Author(s):  
Vijay K. Garg ◽  
Raymond E. Gaugler
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flow ◽  
Film Cooling ◽  
Three Dimensional ◽  
Stagnation Temperature ◽  
Flow Ratio ◽  
Adiabatic Effectiveness ◽  
Mass Flow Ratio

An existing three-dimensional Navier-Stokes code (Arnone et al., 1991), modified to include film cooling considerations (Garg and Gaugler, 1994), has been used to study the effect of spanwise pitch of shower-head holes and coolant to mainstream mass flow ratio on the adiabatic effectiveness and heat transfer coefficient on a film-cooled turbine vane. The mainstream is akin to that under real engine conditions with stagnation temperature = 1900 K and stagnation pressure = 3 MPa. It is found that with the coolant to mainstream mass flow ratio fixed, reducing P, the spanwise pitch for shower-head holes, from 7.5 d to 3.0 d, where d is the hole diameter, increases the average effectiveness considerably over the blade surface. However, when P/d = 7.5, increasing the coolant mass flow increases the effectiveness on the pressure surface but reduces it on the suction surface due to coolant jet lift-off. For P/d = 4.5 or 3.0, such an anomaly does not occur within the range of coolant to mainstream mass flow ratios analyzed. In all cases, adiabatic effectiveness and heat transfer coefficient are highly three-dimensional.

Review of Critical Flowmeters for Gas Flow Measurements

1962 ◽  
Vol 84 (4) ◽  
pp. 447-457 ◽  
Author(s):  
B. T. Arnberg
Keyword(s):  
Mass Flow ◽  
Flow Measurement ◽  
Gas Flow ◽  
Flow Measurements ◽  
Flow Rates ◽  
Real Gas ◽  
Discharge Coefficients ◽  
Critical Nozzles ◽  
Mass Flow Rates ◽  
Flow Functions

Critical flowmeters for accurately measuring the mass flow rates of nonreacting real gases were reviewed. Discussions were presented on theoretical flow functions, on parameters for correlating discharge coefficients, and on the importance of real gas properties. The performance characteristics of critical nozzles and orifices of several designs were reviewed. Approaches were discussed to problems which must be researched before the fullest potential of this type of flow measurement can be realized.

Modeling and Analysis of the Inlet Circumferential Fluctuations in Subsonic Rotors

2017 ◽  
Author(s):  
Mingzhi Tang ◽  
Donghai Jin ◽  
Xingmin Gui
Keyword(s):  
Mass Flow ◽  
Radial Distribution ◽  
Transport Model ◽  
Three Dimensional ◽  
Flow Fields ◽  
Source Terms ◽  
Blade Loading ◽  
Modeling And Analysis ◽  
Blade Passage ◽  
Throughflow Model

Throughflow method has the limitation inherited from the axisymmetric assumption. With this assumption, the effects induced by three-dimensional blade shaping, such as sweep, cannot be sufficiently described. To conquer these shortcomings, a transport model for the circumferential fluctuation (CF) stresses is developed and integrated into a throughflow model. Three subsonic rotors are selected to validate the transport model and investigate the effect of the CF source terms on the flow fields. The results show that the CF source terms can affect the prediction of mass flow, and redistribute the radial distribution of blade loading. Besides, the radial equilibrium at the inlet of the blade passage is also altered by the CF source terms. Moreover, the CF source terms may have different effects for different swept blades.

A One-Dimensional Analytical Method for Turbine Blade Preliminary Cooling Design

2016 ◽  
Author(s):  
Chen Li ◽  
Jian-jun Liu
Keyword(s):  
Mass Flow Rate ◽  
Turbine Blade ◽  
Mass Flow ◽  
Flow Rate ◽  
Film Cooling ◽  
Three Dimensional ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
One Dimensional ◽  
Cooling Design

The turbine blade cooling design is a complex procedure including one-dimensional preliminary cooling design, detailed two-dimensional design and fluid network analyses, and three-dimensional conjugate heat transfer and FEM predictions. Frequent alteration and modification of the cooling configurations make it unpractical to obtain all of three-dimensional design results quickly. Preliminary cooling design deals mainly with the coolant requirements and can be knitted into fluid network to look up the expected cooling structural style to promote three-dimensional geometry design. Previous methods to estimate the coolant requirements of the whole turbine blade in the preliminary cooling design were usually based on the semi-empirical air-cooled blade data. This paper combines turbine blade internal and external cooling, and presents a one-dimensional theoretical analytical method to investigate blade cooling performance, assuming that the coolant temperature increases along the blade span. Firstly, a function of non-dimensional cooling mass flow rate is derived to describe the new relationship between adiabatic film cooling effectiveness and overall cooling effectiveness. Secondly, a new variable related to film cooling is found to estimate the required adiabatic film cooling effectiveness without using the empirical correlations. Finally, a theoretical calculation about the relationship between non-dimensional cooling mass flow rate and overall cooling effectiveness well corresponds to semi-empirical air-cooled blade data within regular range of cooling efficiency. The currently proposed method is also a useful tool for the blade thermal analysis and the sensitivity analysis of coolant requirements to various design parameters. It not only can provide all the possible options at the given gas and coolant inlet temperatures to meet the design requirement, but also can give the third boundary conditions for calculating the blade temperature field. It’s convenient to use the heat transfer characteristic of internal cooling structures to estimate the coolant mass flow rate and the channel hydraulic diameter for both convection cooling and film cooling.

scholarly journals Improved evaluation of granular media flows using an X-ray scanning compatible cone-plate setup

2021 ◽  
Vol 249 ◽  
pp. 03020
Author(s):  
Zohreh Farmani ◽  
Jing Wang ◽  
Ralf Stannarius ◽  
Martina Bieberle ◽  
Frank Barthel ◽  
...  
Keyword(s):  
Granular Materials ◽  
High Speed ◽  
Granular Media ◽  
Flow Behavior ◽  
Three Dimensional ◽  
High Speed Imaging ◽  
Flow Measurements ◽  
Flow Rates ◽  
X Ray ◽  
Wide Range

To understand the typically heterogeneous flowing behavior of granular materials, it is important to combine flow tests with three-dimensional imaging. To probe the flow behavior of granular materials over a wide range of flow rates, it is imperative to be able to impose such flow rates in a well controlled manner while performing imaging tests that are compatible with all imposed flow rates. Achieving both flow control and bulk imaging capacity is challenging for a number of reasons. Here, we describe the design of a setup in which we are able to do imaging while imposing a constant overall shear rate on a granular material. We characterize the setup in which flow tests will be performed, which consists of a bottom-driven cone-plate or double-cone design. We show that the setup can be integrated in x-ray microtomography devices to aid particle tracking based flow measurements. The design is also compatible with typical rheometer setups. We also perform high speed imaging of a granular flow in an ultra-fast x-ray scanner, for which we provide proof-of-principle data in a simplified shear setup. The designed flow geometry is also compatible with said high speed imaging facility, where particle image velocimetry can be employed to extract quantitative flow field data.

Large Eddy Simulation of Film Cooling Flow From an Inclined Cylindrical Jet

2003 ◽  
Author(s):  
Sumanta Acharya ◽  
Mayank Tyagi
Keyword(s):  
Flow Field ◽  
Film Cooling ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Wake Region ◽  
Complex Flow ◽  
Mixing Processes ◽  
Hairpin Vortices ◽  
Flow Measurements ◽  
Large Eddy

Predictions of turbine blade film cooling have traditionally employed Reynolds averaged Navier Stokes (RANS) solvers and two-equation models for turbulence. Evaluation of several versions of such models have revealed that the existing two equation models fail to resolve the anisotropy and the dynamics of the highly complex flow field created by the jet-crossflow interaction. A more accurate prediction of the flow field can be obtained from large eddy simulations (LES) where the dynamics of the larger scales in the flow are directly resolved. In the present paper, such an approach has been used, and results are presented for a row of inclined cylindrical holes at blowing ratios of 0.5 and 1, and a Reynolds number of 11100 and 22200 respectively based on the jet velocity and hole diameter. Comparison of the time-averaged LES predictions with the flow measurements of Lavrich and Chiappetta [1] shows that LES is able to predict the flow field with reasonable accuracy. The unsteady three-dimensional flow field is shown to be dominated by packets of hairpin shaped vortices. The dynamics of the hairpin vortices in the wake region of the injected jet and their influence on the unsteady wall heat transfer is presented. Generation of “hot spots” and their migration on the film-cooled surface is associated with the entrainment induced by the hairpin structures. Several geometric properties of a “mixing interface” around hairpin coherent structures are presented to illustrate and quantify their impact on the entrainment rates and mixing processes in the wake region.

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