Effective turbine blade cooling is necessary to enhance the efficiency of gas turbines. Usually the coolant is mainly ejected through the trailing edge of the vanes. In addition to the desired temperature reduction at the trailing edge there is a 3D-aerodynamical interaction between the hot gas and the coolant. The complex mechanisms of the mixture are a main problem in the numerical prediction of the flow situation in this region. This paper presents the experimental and numerical results of investigations of annular guide vanes. The experiments were conducted in a scaled turbine test rig. The mixing flow of coolant and hot gas was analyzed by measurement of the distribution of both velocity and turbulence very close to the trailing edge using a 2D-LDA measurement technique at different radial positions. The experimental results show that the radial and circumferential distribution of the coolant depends on the pressure gradient in both directions. Inside of the mixture region the turbulence was found to be anisotropic resulting in a non-symmetrical distribution of the coolant. For the numerical calculations a Navier-Stokes-Code was used. The numerical scheme works on the basis of an implicit finite volume method combined with a multi block technique. In order to simulate the aerodynamical effects near the injection slot of the vane it was nessessary to include the coolant flow inside the guide vane.

SHAMS 1 ("Shams" means "Sun" in Arabic) Concentrated Solar Power plant is a very successful example of a modern plant, which combines the known configuration of a parabolic trough technology with the well-established power generation technologies operated at 540°C live steam temperature while respecting the specific requirement of the daily starts and shutdowns. In addition to the high live steam temperature challenge and being located in the middle of the desert approx. 120 km south west of the city of Abu Dhabi, the plant has to face, the plant has to fact several atmospheric challenges like the high dust concentration, wind storms, and high ambient temperature. This paper, written jointly by Shams Power Company-the project and operating company and MAN Diesel & Turbo-the steam turbine original manufacturer, describes the challenges in optimizing the design of the steam turbine to fulfill the requirement of fast start up while operating the plant on daily transient pattern for minimum 30 years. It also addresses the several atmospheric challenges and how the project and operating company has overcame them. Finally, the paper gives a snap shot on the operational experience and record of the plant showing that despite the very challenging environment, the budgeted target has been exceeded in the first two years of operation. UNIQUE PLANT CONCEPT It was obvious from the very first day on this project that it will be very challenging to design a 100 MW Concentrated Solar Power (CSP) plant in the middle of the harsh desert environment. The task was not only to design the-to that time-largest CSP plant in the world, but also to demonstrate the ability to overcome technology limits given by the limited temperature of the thermal oil, used as the Heat Transfer Fluid (HTF), which is known to suffer high rate of degradations at temperatures close to 400°C. Such limitation to the temperature of the HTF obviously results in limited thermodynamic cycle efficiency. With Abu Dhabi Future Energy Company-Masdar as the leading partner, TOTAL and Abengoa Solar 1 , the project partners targeted to increase the daily electricity power output from the relative moderate level of the established 380°C CSP plant applications to the maximal known level by introducing three key improvements:

Experimental investigations have been carried out to analyze the hot gas flow and cooling gas flow in the direct vicinity of the trailing edge of a modern gas turbine vane, with cooling gas ejection through the trailing edge. The investigations were performed in one of the institute’s test turbines. The experimental set-up is designed to establish variable blowing ratios between cooling gas mass flow and hot gas mass flow. An alternative density ratio between hot gas and cooling gas was established by the use of CO2 instead of air as the cooling gas for cold test runs. The experimental investigations have been carried out for different radial positions. The measurement plane was located 0.2mm to 0.5mm downstream of the trailing edge (trailing edge width 1.6mm). Local regions of high anisotropic turbulence were detected in the mixing zone. For low blowing ratios, the trailing edge pressure side in the tip vicinity was found to be subjected to direct hot gas contact. The trailing edge ejection has an influence of at least one chordlength in axial direction. The experimental investigations were accompanied by 3-D Navier-Stokes computational simulations. The calculated velocity distributions were found to be quite consistent with the experimental results. The calculated flow angles differed locally from the measurements. This may be due to the turbulence model employed.

Subject of the paper is to present a purpose-built steam turbine test rig and its prospects for complex analysis of thermodynamic, aerodynamic and mechanical problems. The turbine at a scale of 1:1 was equipped with extensive instrumentation. Pressure and temperature rakes behind the control stage at several circumferential positions, rakes before and behind the HP, IP and LP stages and additional 5-hole probes to measure the complete flow field. Also tip timing measurement of the last LP stages were carried out to analyze their mechanic behavior in critical operating points, for example extreme part load or high condenser pressure. The turbine and its equipment are discussed, different operating points are analyzed and some comparisons of measurement results and numeric calculations are presented. The measurements create an additional database for future design optimizations. NOMENCLATURESUBSCRIPTS h height dimensionless ave averaged p pressure m mean r radius stat static t time tot total T Temperature