Preliminary Design and Projected Performance for Intercooled-Recuperated Microturbine

2008 ◽  
Author(s):  
Thomas L. Wolf ◽  
James B. Kesseli ◽  
James S. Nash
Keyword(s):  
High Pressure ◽  
High Efficiency ◽  
Power Level ◽  
Pressure Ratio ◽  
Turbine Rotor ◽  
Preliminary Design ◽  
High Pressure Turbine ◽  
Engine Design ◽  
Power Turbine ◽  
Ceramic Components

The Inter-Cooled-Recuperated (ICR) cycle is recognized for its high efficiency potential in gas-turbine applications. This paper reports on a proposed implementation of the ICR cycle in a microturbine setting, using a three-spool configuration incorporating a variable-geometry nozzle on the low-pressure ‘free’ power turbine. Hardware specified for the high-pressure turbine is an existing ceramic rotor fabricated and spin-tested in connection with a prior DOE-sponsored program. Rated engine design-point power and efficiency are projected at 378kWe and 39.5% (net LHV), under realistic prescriptions for component efficiencies and parasitic losses, and with TIT = 1366K (2000°F) specified for the ceramic rotor. Detailed off-design performance projections are carried out, demonstrating exceptional range and part-load efficiency. A key attraction of the ICR compared to a non-intercooled recuperated cycle is its compatibility with high cycle pressure ratio, making for dramatic size and cost reductions for high-pressure components, most importantly the recuperator. A related advantage is reduced ceramic-turbine rotor diameter for a given power level, extending the applicability of ceramic components under conservative manufacturability limits. Engine layout and preliminary mechanical designs for the major subassemblies are developed for application to a forty-foot transport bus with hybrid-electric drive. Further applications under evaluation for the proposed microturbine are stationary power generation, and in a hybrid powerplant setting using a solid-oxide fuel cell.

A Generalized Procedure to Estimate Matching of Power Turbine With Aeroderivative Gas Generator at High Speed Settings

2005 ◽  
Author(s):  
Inam U. Haq
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Pressure Ratio ◽  
Gas Generator ◽  
High Pressure Turbine ◽  
Data Manipulation ◽  
Turbine Inlet ◽  
Engine Design ◽  
Power Turbine ◽  
Set Up

This paper encapsulates generalized considerations of power turbine matching with aeroderivative gas generator at high power settings. A computation route is set up to estimate the magnitude of the desired parameters from design point knowledge of a gas generator. Then, a method is delineated to verify matching of power turbine inlet nozzle area with exhaust of gas generator by measuring tangible tested parameters. Data manipulation revealed that there exists a favorable correlation between pressure ratio of high pressure turbine and gas generator speed that may directly reflect the influence of physical area change of power turbine inlet nozzle area. A practical example is presented to demonstrate the procedure. From engine design to retirement, the generalized considerations may be applied on several occasions where question of matching may become important and require explanation for performance and financial justifications. Some generalized rules of matching are condensed and their applications are suggested.

scholarly journals A 3-Shaft Gas Turbine to Meet Automotive Requirements

1967 ◽  
Author(s):  
P. J. Collet
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Variable Geometry ◽  
Automotive Applications ◽  
High Pressure Turbine ◽  
Part Load ◽  
Power Turbine ◽  
Novel Method ◽  
Design Pressure

At present the regenerative, low-pressure, 2-shaft gas turbine seems to be the generally accepted cycle layout for automotive applications. The performance of such an arrangement in its simplest form is assessed with regard to sfc (especially at part load), engine response, torque characteristics, and engine braking capability. The application of variable geometry, e.g., movable power-turbine nozzles, can be used to reduce part-load sfc in addition to providing engine braking. A more drastic approach towards improving performance to meet automotive requirements is described in this paper. The addition of a “turbocharger,” two freewheels, and variable high-pressure turbine nozzles results in an increased specific output, decreased fuel consumption, a higher torque ratio permitting a simplified transmission, and a major braking capability. Significant features of this 3-shaft arrangement include the retention of a comparatively low design pressure ratio and a novel method of maintaining adequate engine response.

scholarly journals Rapid Airfoil Design for Uncooled High Pressure Turbine Blades

2015 ◽  
Author(s):  
Niloofar Moradi ◽  
Edward Vlasic ◽  
Hany Moustapha
Keyword(s):  
High Pressure ◽  
System Integration ◽  
Turbine Blades ◽  
Turnaround Time ◽  
Preliminary Design ◽  
Generation Process ◽  
Design Phase ◽  
High Pressure Turbine ◽  
Engine Design ◽  
House Design

The aero-engine design process is highly iterative, multidisciplinary in nature and complex. The success of any engine design depends on best exploiting and considering the interactions among the numerous traditional engineering disciplines such as aerodynamics and structures. More emphasis has been placed lately on system integration, cross disciplines leveraging of tools and multi-disciplinary-optimization at the preliminary design phase. This paper investigates the automation of the airfoil generation process, referred to as Rapid Airfoil 3D (RAF 3D), for uncooled high pressure turbine blades at the preliminary design phase. This Matlab based program, uses the turbine aero meanline (TAML) in parallel with a database of previously designed P&WC airfoils, in-house design rules and best practices to define a pre-detailed airfoil shape which can be fed back to other analytical groups for pre-detail analyses, such as for structures and vibrations. Resulting airfoil shapes have been aerodynamically validated using an in-house 3D RANS code. RAF 3D will shorten the turnaround time for P&WC’s turbine aerodynamics group to provide a preliminary 3D airfoil shape to turbine structures group by up to a factor of ten. Additionally, the preliminary assessments of stress and vibration specialists will be more accurate as their assessments will be based on an airfoil that has had inputs from all functional groups even though it is “first pass” design.

Influence of Hot Streak Temperature Ratio on Low Pressure Stage of a Vaneless Counter-Rotating Turbine

2007 ◽  
Author(s):  
Qingjun Zhao ◽  
Fei Tang ◽  
Huishe Wang ◽  
Jianyi Du ◽  
Xiaolu Zhao ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Secondary Flow ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Pressure Stage ◽  
Low Pressure Turbine ◽  
Hot Streak

In order to explore the influence of hot streak temperature ratio on low pressure stage of a Vaneless Counter-Rotating Turbine, three-dimensional multiblade row unsteady Navier-Stokes simulations have been performed. The predicted results show that hot streaks are not mixed out by the time they reach the exit of the high pressure turbine rotor. The separation of colder and hotter fluids is observed at the inlet of the low pressure turbine rotor. After making interactions with the inner-extending shock wave and outer-extending shock wave in the high pressure turbine rotor, the hotter fluid migrates towards the pressure surface of the low pressure turbine rotor, and the most of colder fluid migrates to the suction surface of the low pressure turbine rotor. The migrating characteristics of the hot streaks are predominated by the secondary flow in the low pressure turbine rotor. The effect of buoyancy on the hotter fluid is very weak in the low pressure turbine rotor. The results also indicate that the secondary flow intensifies in the low pressure turbine rotor when the hot streak temperature ratio is increased. The effects of the hot streak temperature ratio on the relative Mach number and the relative flow angle at the inlet of the low pressure turbine rotor are very remarkable. The isentropic efficiency of the Vaneless Counter-Rotating Turbine decreases as the hot streak temperature ratio is increased.

Impact of Individual High-Pressure Turbine Rotor Purge Flows on Turbine Center Frame Aerodynamics

2017 ◽  
Author(s):  
S. Zerobin ◽  
C. Aldrian ◽  
A. Peters ◽  
F. Heitmeir ◽  
E. Göttlich
Keyword(s):  
High Pressure ◽  
Pressure Loss ◽  
Turbine Rotor ◽  
Flow Conditions ◽  
High Pressure Turbine ◽  
Reference Case ◽  
University Of Technology ◽  
Purge Flow ◽  
Generation Mechanisms ◽  
The Impact

This paper presents an experimental study of the impact of individual high-pressure turbine purge flows on the main flow in a downstream turbine center frame duct. Measurements were carried out in a product-representative one and a half stage turbine test setup, installed in the Transonic Test Turbine Facility at Graz University of Technology. The rig allows testing at engine-relevant flow conditions, matching Mach, Reynolds, and Strouhal number at the inlet of the turbine center frame. The reference case features four purge flows differing in flow rate, pressure, and temperature, injected through the hub and tip, forward and aft cavities of the high-pressure turbine rotor. To investigate the impact of each individual cooling flow on the flow evolution in the turbine center frame, the different purge flows were switched off one-by-one while holding the other three purge flow conditions. In total, this approach led to six different test conditions when including the reference case and the case without any purge flow ejection. Detailed measurements were carried out at the turbine center frame duct inlet and outlet for all six conditions and the post-processed results show that switching off one of the rotor case purge flows leads to an improved duct performance. In contrast, the duct exit flow is dominated by high pressure loss regions if the forward rotor hub purge flow is turned off. Without the aft rotor hub purge flow, a reduction in duct pressure loss is determined. The purge flows from the rotor aft cavities are demonstrated to play a particularly important role for the turbine center frame aerodynamic performance. In summary, this paper provides a first-time assessment of the impact of four different purge flows on the flow field and loss generation mechanisms in a state-of-the-art turbine center frame configuration. The outcomes of this work indicate that a high-pressure turbine purge flow reduction generally benefits turbine center frame performance. However, the forward rotor hub purge flow actually stabilizes the flow in the turbine center frame duct and reducing this purge flow can penalize turbine center frame performance. These particular high-pressure turbine/turbine center frame interactions should be taken into account whenever high-pressure turbine purge flow reductions are pursued.

Time-Averaged and Time-Accurate Aerodynamic Effects of Forward Rotor Cavity Purge Flow for a High-Pressure Turbine: Part I—Analytical and Experimental Comparisons

2012 ◽  
Author(s):  
Brian R. Green ◽  
Randall M. Mathison ◽  
Michael G. Dunn
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Flow Path ◽  
Field Analysis ◽  
High Pressure Turbine ◽  
Purge Flow

The effect of rotor purge flow on the unsteady aerodynamics of a high-pressure turbine stage operating at design corrected conditions has been investigated both experimentally and computationally. The experimental configuration consisted of a single-stage high-pressure turbine with a modern film-cooling configuration on the vane airfoil as well as the inner and outer end-wall surfaces. Purge flow was introduced into the cavity located between the high-pressure vane and the high-pressure disk. The high-pressure blades and the downstream low-pressure turbine nozzle row were not cooled. All hardware featured an aerodynamic design typical of a commercial high-pressure ratio turbine, and the flow path geometry was representative of the actual engine hardware. In addition to instrumentation in the main flow path, the stationary and rotating seals of the purge flow cavity were instrumented with high frequency response, flush-mounted pressure transducers and miniature thermocouples to measure flow field parameters above and below the angel wing. Predictions of the time-dependent flow field in the turbine flow path were obtained using FINE/Turbo, a three-dimensional, Reynolds-Averaged Navier-Stokes CFD code that had the capability to perform both steady and unsteady analysis. The steady and unsteady flow fields throughout the turbine were predicted using a three blade-row computational model that incorporated the purge flow cavity between the high-pressure vane and disk. The predictions were performed in an effort to mimic the design process with no adjustment of boundary conditions to better match the experimental data. The time-accurate predictions were generated using the harmonic method. Part I of this paper concentrates on the comparison of the time-averaged and time-accurate predictions with measurements in and around the purge flow cavity. The degree of agreement between the measured and predicted parameters is described in detail, providing confidence in the predictions for flow field analysis that will be provided in Part II.

Aerodynamic Performance of an Unlocated High Pressure Turbine Rotor With Worn Tip Seal Fins

2017 ◽  
Author(s):  
Lucas Pawsey ◽  
David John Rajendran ◽  
Vassilios Pachidis
Keyword(s):  
High Pressure ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Aerodynamic Performance ◽  
Axial Displacement ◽  
High Pressure Turbine ◽  
Design Modification ◽  
Turbine Casing ◽  
Secondary Air ◽  
Shaft Failure

An unlocated shaft failure in the high pressure turbine spool of an engine may result in a complex orbiting motion along with rearward axial displacement of the high pressure turbine rotor sub-assembly. This is due to the action of resultant forces and limitations imposed by constraints such as the bearings and turbine casing. Such motion of the rotor following an unlocated shaft failure, results in the development of multiple contacts between the components of the rotor sub-assembly, the turbine casing, and the downstream stator casing. Typically, in the case of shrouded rotor blades, the tip region is in the form of a seal with radial protrusions called ‘fins’ between the rotor blade and the turbine casing. The contact between the rotor blade and the turbine casing will therefore result in excessive wear of the tip seal fins, resulting in changes in the geometry of the tip seal domain that affects the characteristics of the tip leakage vortex. The rotor sub-assembly with worn seals may also be axially displaced rearwards, and consequent to this displacement, changes in the geometry of the rotor blade may occur because of the contact between the rotor sub-assembly and the downstream stator casing. An integrated approach of structural analyses, secondary air system dynamics, and 3D CFD is adopted in the present study to quantify the effect of the tip seal damage and axial displacement on the aerodynamic performance of the turbine stage. The resultant geometry after wearing down of the fins in the tip seal, and rearward axial displacement of the rotor sub-assembly is obtained from LS-DYNA simulations. 3D RANS analyses are carried out to quantify the aerodynamic performance of the turbine with worn fins in the tip seal at three different axial displacement locations i.e. 0 mm, 10 mm and 15 mm. The turbine performance parameters are then compared with equivalent cases in which the fins in the tip seal are intact for the same turbine axial displacement locations. From this study it is noted that the wearing of tip seal fins results in reduced turbine torque, power output and efficiency, consequent to changes in the flow behaviour in the turbine passages. The reduction in turbine torque will result in the reduction of the terminal speed of the rotor during an unlocated shaft failure. Therefore, a design modification that can lead to rapid wearing of the fins in the tip seal after an unlocated shaft failure holds promise for the management of a potential over-speed event.

Development of New Single and High-Density Heat-Flux Gauges for Unsteady Heat Transfer Measurements for a Rotating Transonic Turbine

2020 ◽  
Author(s):  
Richard Celestina ◽  
Spencer Sperling ◽  
Louis Christensen ◽  
Randall Mathison ◽  
Hakan Aksoy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
Pressure Ratio ◽  
High Density ◽  
Secondary Flows ◽  
Single Stage ◽  
High Pressure Turbine ◽  
Transonic Turbine ◽  
New Generation

Abstract This paper presents the development and implementation of a new generation of double-sided heat-flux gauges at The Ohio State University Gas Turbine Laboratory (GTL) along with heat transfer measurements for film-cooled airfoils in a single-stage high-pressure transonic turbine operating at design corrected conditions. Double-sided heat flux gauges are a critical part of turbine cooling studies, and the new generation improves upon the durability and stability of previous designs while also introducing high-density layouts that provide better spatial resolution. These new customizable high-density double-sided heat flux gauges allow for multiple heat transfer measurements in a small geometric area such as immediately downstream of a row of cooling holes on an airfoil. Two high-density designs are utilized: Type A consists of 9 gauges laid out within a 5 mm by 2.6 mm (0.20 inch by 0.10 inch) area on the pressure surface of an airfoil, and Type B consists of 7 gauges located at points of predicted interest on the suction surface. Both individual and high-density heat flux gauges are installed on the blades of a transonic turbine experiment for the second build of the High-Pressure Turbine Innovative Cooling program (HPTIC2). Run in a short duration facility, the single-stage high-pressure turbine operated at design-corrected conditions (matching corrected speed, flow function, and pressure ratio) with forward and aft purge flow and film-cooled blades. Gauges are placed at repeated locations across different cooling schemes in a rainbow rotor configuration. Airfoil film-cooling schemes include round, fan, and advanced shaped cooling holes in addition to uncooled airfoils. Both the pressure and suction surfaces of the airfoils are instrumented at multiple wetted distance locations and percent spans from roughly 10% to 90%. Results from these tests are presented as both time-average values and time-accurate ensemble averages in order to capture unsteady motion and heat transfer distribution created by strong secondary flows and cooling flows.

Linear Deterministic Source Terms for Hot Streak Simulations

2000 ◽  
Author(s):  
Paul D. Orkwis ◽  
Mark G. Turner ◽  
John W. Barter
Keyword(s):  
Boundary Condition ◽  
High Pressure ◽  
Source Term ◽  
Aircraft Engine ◽  
Turbine Rotor ◽  
High Pressure Turbine ◽  
Order Of Accuracy ◽  
Time Average ◽  
Hot Streak ◽  
Unsteady Effects

Steady state surface rothalpy results obtained with a lumped deterministic source term are compared with results obtained from a traditional nonlinear inviscid unsteady solution for an aircraft engine first stage high-pressure turbine rotor configuration. Boundary condition/potential field effects and the order of accuracy of the available schemes are shown to have a significant effect on surface rothalpy results. However, the new technique demonstrates a significant potential for including unsteady effects in time average calculations with minimal computer effort.

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