Begell House Inc.
Heat Transfer Research
HTR
1064-2285
42
2
2011
Special Issue 5 of 5:Turbine-09 symposium, Antalya, Turkey, August 9−14, 2009Guest Editors:TerrenceW. Simon & Richard J. Goldstein
0
10.1615/HeatTransRes.v42.i2.10
Preface: Gas Turbine Heat Transfer
99-100
10.1615/HeatTransRes.v42.i2.20
This issue has papers selected by the Scientific Committee from the symposium Turbine-09 sponsored by the International Center for Heat and Mass Transfer (ICHMT). Turbine-09 was held in Antalya, Turkey, August 9−14, 2009. It was the third symposium related to heat transfer in high-performance gas turbines sponsored by the ICHMT. The first, held in Marathon, Greece, in August 1992, resulted in the book Heat Transfer in Turbomachinery. The second, Turbine 2000, conducted in Cesme, Turkey, in August 2000, was published in the book Heat Transfer in Gas Turbine Systems. The three symposia offered invited keynote lectures and contributed papers by some of the world’s best-known authorities on gas turbine heat transfer. Each of the two proceedings volumes and these special issues (Vol. 41, Nos. 6−8, 2010 and Vol. 42, Nos. 1 and 2, 2011) contain a wealth of information from key industrial, academic, and nonprofit laboratories.
The objective of the symposium and of these special issues is to provide an opportunity to present and review the most recent developments in heat transfer and thermal control applied to modern, high-temperature gas turbine systems. Presented are: experimental results and techniques, computational studies and methods, and design recommendations. Aspects of heat transfer in rotating machinery include:
combustor and transition section heat transfer,
heat exchange to turbine airfoil and endwall surfaces within the gas path,
stator internal heat transfer,
disk cavity and blade internal flow and heat transfer,
innovative cooling techniques, and
heat exchange in turbines with combined cycles.
The results published in these issues should be valuable to researchers in heat transfer as well as to designers of gas turbine systems.
Multiple Jet Impingement − A Review
101-142
10.1615/HeatTransRes.v42.i2.30
Bernhard
Weigand
Institute of Aerospace Thermodynamics (ITLR), University of Stuttgart,
Pfaffenwaldring 31, D-70569 Stuttgart, Germany
Sebastian
Spring
Institute of Aerospace Thermodynamics (ITLR), Unversitüt Stuttgart, Germany
jet impingement heat transfer
review
multiple jets
turbulent flow
experiments
CFD
correlation
A review of the heat transfer characteristics of systems of multiple impinging air jets is presented. The objective is to provide a profound physical knowledge for the design of these impingement configurations, for which the factors that influence heat transfer are categorized and illustrated by exemplary results collated from different sources. In the course of the review, the flow and heat transfer characteristics of multiple impinging jets are introduced and compared to single impinging jets. Influencing factors on heat transfer are discussed, which include the effects of crossflow, jet Reynolds number, jet pattern, separation distance between a jet and target plate, and of the open area. An overview of the studies considering optimization and heat transfer enhancement is provided. In the review of numerical works, the suitability of the present CFD tools in predicting local heat transfer rates for multi-jet systems is discussed. Developments in the measurement technique and numerical accuracy are summarized. The review concludes with a summary and comparison of empirical correlations for both total average and locally resolved heat transfer coefficients.
Influence of Internal Cyclone Flow on Adiabatic Film Cooling Effectiveness
143-164
10.1615/HeatTransRes.v42.i2.40
Andreas
Lerch
Institute of Gas Turbines and Aerospace Propulsion, Technische Universität Darmstadt, 64287 Darmstadt, Germany
Heinz-Peter
Schiffer
Institute of Gas Turbines and Aerospace Propulsion, Technische Universität Darmstadt, 64287 Darmstadt, Germany
turbine blade
leading edge
ammonia diazo
swirl
experimental
blowing ratio
The adiabatic film cooling effectiveness on the surface of a symmetrical blade model was measured for eight cylindrical, 59° inclined cooling holes. The holes were fed with different flow types using a cylindrical leading-edge channel. Two configurations were compared: on the one hand, a leading-edge channel flow without swirl (datum configuration), using a sharp-edged inlet; on the other hand, a new cyclone cooling configuration with a positive swirl. The experiments were carried out using the calibrated ammonia diazo technique. The blowing ratios were varied between 0.6 and 1.2, and the film cooling discharge was set to either 20% or 50%. For all these operation points, multiple experiments were conducted and combined using a weighting average method to produce a high full-range resolution. The lateral and area-averaged adiabatic effectiveness is presented up to 45D downstream of the cooling holes. The measurements show a higher area-averaged effectiveness immediately downstream of the cooling holes when using the cyclone cooling configuration. This is due to nonsymmetric flow structures inside the cooling holes. Further downstream, however, it decreases faster. With a low film cooling discharge and rising blowing ratios, these effects are more pronounced.
Advanced Aero-Thermal Investigation of High-Pressure Turbine Tip Flows
165-180
10.1615/HeatTransRes.v42.i2.50
Peter
Vass
Turbomachinery & Propulsion Department, Von Kármán Institute for Fluid Dynamics, Rhode-Saint-Genése, B-1640, Belgium
Tony
Arts
Turbomachinery & Propulsion Department, Von Kármán Institute for Fluid Dynamics, Rhode-Saint-Genése, B-1640, Belgium
gas turbine
heat transfer
blade tip
leakage
numerical simulation
turbulent flow
grid generation
parallel calculations
The present contribution gives an overview of the numerical work performed at the Von Kármán Institute in the framework of the European research program AITEB-2, concerning the numerical investigation of tip gap flows in linear turbomachinery cascades, representatives of high-pressure turbine rotor blade geometries. The primary goal of the project is the simulation of flow and heat transfer on four distinct blade tip geometries in 3D, including the entire internal cooling setup inside a blade, the validation of the results versus the experimental campaign of Hofer et al. [1] and evaluation of the geometries. The paper presents the computations performed on the first tip geometry (TG1 hereinafter) with recessed tip. The geometry and the numerical setup are described in detail, with emphasis on the grid generation and connection method between internal and external flows.
Validation is introduced on the most delicate, zero cooling flow case, in which internal flow in the cooling channels is driven exclusively by pressure difference between pressure side tip region and tip gap. The comparison with experiments is performed for one exit Reynolds number (Re = 900,000), and two exit Mach numbers; M = 0.8 (HRLM) and M = 1.1 (HRHM). Flow visualization is performed and set against experimental oil flow visualization; the basic features of the flow topology are analyzed. Typical results of from heat transfer simulations are shown in both test cases.
Liquid Crystal Thermography for Transient Heat Transfer Measurements in Complex Internal Cooling Systems
181-197
10.1615/HeatTransRes.v42.i2.60
Rico
Poser
Institute of Aerospace Thermodynamics (ITLR), Universitüt Stuttgart, Germany
Jens
von Wolfersdorf
Institute of Aerospace Thermodynamics, University of Stuttgart, Germany
thermochromic liquid crystals (TLCs)
transient heat transfer measurements
complex internal cooling systems
Thermochromic Liquid Crystals (TLCs) are frequently applied as optical temperature sensors for transient heat transfer measurements. Typical examples include the investigation of heat transfer characteristics for cooled gas turbine components using models manufactured from optical-transparent materials. By applying a suddenly changing fluid temperature to a test specimen, a delayed wall temperature response occurs that is monitored on the surface using TLCs and observed with a digital color video camera. Common evaluation techniques associate a calibrated temperature to a unique TLC hue value or peak intensity and detect the corresponding surface response time. Assuming one-dimensional heat conduction in a semi-infinite medium with a convective boundary condition, the analytical solution of Fourier's equation can be applied to calculate local heat transfer distributions. Besides the application of this measurement technique to large-scaled models of simplified representative parts of cooling systems, the investigation of full complex cooling configurations requires special considerations. To account for engine relevant conditions, these models need to represent the actual machine geometry including different surface curvature conditions, individual coolant flow distributions, flow extraction locations and small scale features. The paper presents some new developments associated with the application of the transient heat transfer measurement technique for such complex cooling systems.