Effects of Temperature and Particle Size on Deposition in Land Based Turbines

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Jared M. Crosby ◽  
Scott Lewis ◽  
Jeffrey P. Bons ◽  
Weiguo Ai ◽  
Thomas H. Fletcher
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Deposition Process ◽  
Capture Efficiency ◽  
Test Series ◽  
Test Facility ◽  
Back Side ◽  
Gas Temperature ◽  
The Third ◽  
Barrier Coating

Four series of tests were performed in an accelerated deposition test facility to study the independent effects of particle size, gas temperature, and metal temperature on ash deposits from two candidate power turbine synfuels (coal and petcoke). The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes while accelerating the deposition process. Particle size was found to have a significant effect on capture efficiency with larger particles causing significant thermal barrier coating (TBC) spallation during a 4 h accelerated test. In the second series of tests, particle deposition rate was found to decrease with decreasing gas temperature. The threshold gas temperature for deposition was approximately 960°C. In the third and fourth test series, impingement cooling was applied to the back side of the target coupon to simulate internal vane cooling. Capture efficiency was reduced with increasing mass flow of coolant air; however, at low levels of cooling, the deposits attached more tenaciously to the TBC layer. Postexposure analyses of the third test series (scanning electron microscopy and X-ray spectroscopy) show decreasing TBC damage with increased cooling levels.

Effects of Particle Size, Gas Temperature and Metal Temperature on High Pressure Turbine Deposition in Land Based Gas Turbines From Various Synfuels

2007 ◽  
Author(s):  
Jared M. Crosby ◽  
Scott Lewis ◽  
Jeffrey P. Bons ◽  
Weiguo Ai ◽  
Thomas H. Fletcher
Keyword(s):  
Particle Size ◽  
High Pressure ◽  
Coal Ash ◽  
Capture Efficiency ◽  
Metal Temperature ◽  
Test Series ◽  
Gas Temperature ◽  
High Pressure Turbine ◽  
The Third ◽  
Power Turbine

Four series of tests were performed in an accelerated deposition test facility to study the independent effects of particle size, gas temperature, and metal temperature on ash deposits from two candidate power turbine synfuels. The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes while accelerating the deposition process. This is done by matching the net throughput of particulate out of the combustor with that experienced by a modern power turbine. In the first series of tests, four different size particles were studied by seeding a natural-gas combustor with finely-ground coal ash particulate. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.25 before impinging on a thermal barrier coated (TBC) target coupon at 1183°C. Particle size was found to have a significant effect on capture efficiency with larger particles causing significant TBC spallation during a 4-hour accelerated test. In the second series of tests, different gas temperatures were studied while the facility maintained a constant exit velocity of 170m/s (Mach = 0.23–0.26). Coal ash with a mass mean diameter of 3 μm was used. Particle deposition rate was found to decrease with decreasing gas temperature. The threshold gas temperature for deposition was approximately 960°C. In the third and fourth test series impingement cooling was applied to the backside of the target coupon to simulate internal vane cooling. Ground coal and petcoke ash particulates were used for the two tests respectively. Capture efficiency was reduced with increasing massflow of coolant air, however at low levels of cooling the deposits attached more tenaciously to the TBC layer. Post exposure analyses of the third test series (scanning electron microscopy and x-ray spectroscopy) show decreasing TBC damage with increased cooling levels. Implications for the power generation goal of fuel flexibility are discussed.

scholarly journals A Numerical Study of the Effect of Particle Size on Particle Deposition on Turbine Vanes and Blades

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110178
Author(s):  
Zhengang Liu ◽  
Weinan Diao ◽  
Zhenxia Liu ◽  
Fei Zhang
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Numerical Study ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Particle Capture ◽  
Factors Affecting ◽  
Pressure Surface ◽  
Deposition Area ◽  
Turbine Vanes

Particle deposition could decrease the aerodynamic performance and cooling efficiency of turbine vanes and blades. The particle motion in the flow and its temperature are two important factors affecting its deposition. The size of the particle influences both its motion and temperature. In this study, the motion of particles with the sizes from 1 to 20 μm in the first stage of a turbine are firstly numerically simulated with the steady method, then the particle deposition on the vanes and blades are numerically simulated with the unsteady method based on the critical viscosity model. It is discovered that the particle deposition on vanes mainly formed near the leading and trailing edge on the pressure surface, and the deposition area expands slowly to the whole pressure surface with the particle size increasing. For the particle deposition on blades, the deposition area moves from the entire pressure surface toward the tip with the particle size increasing due to the effect of rotation. For vanes, the particle capture efficiency increases with the particle size increasing since Stokes number and temperature of the particle both increase with its size. For blades, the particle capture efficiency increases firstly and then decreases with the particle size increasing.

scholarly journals Experimental Study of Sand Particle Deposition on a Film-Cooled Turbine Blade at Different Gas Temperatures and Angles of Attack

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 811 ◽  
Author(s):  
Fei Zhang ◽  
Zhenxia Liu ◽  
Zhengang Liu ◽  
Weinan Diao
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Particle Deposition ◽  
Angle Of Attack ◽  
Large Angle ◽  
Capture Efficiency ◽  
Gas Temperature ◽  
Trailing Edge ◽  
Pressure Surface ◽  
Film Cooling Holes

Particle deposition tests were conducted in a turbine deposition facility with an internally staged single-tube combustor to investigate the individual effect of the gas temperature and angle of attack. Sand particles were seeded to the combustor and deposited on a turbine blade with film-cooling holes at temperatures representative of modern engines. Fuel-air ratios were varied from 0.022 to 0.037 to achieve a gas temperature between 1272 and 1668 K. Results show that capture efficiency increased with increasing gas temperature. A dramatic increase in capture efficiency was noted when gas temperature exceeded the threshold. The deposition formed mostly downstream of the film-cooling holes on the pressure surface, while it concentrated on the suction surface at the trailing edge. Deposition tests at angles of attack between 10° and 40° presented changes in both deposition mass and distribution. The capture efficiency increased with the increase in the angle of attack, and simultaneously the growth rate slowed down. On the blade pressure surface, sand deposition was distributed mainly downstream of the film-cooling holes near the trailing edge in the case of the small angle of attack, while it concentrated on the region around the film-cooling holes near the leading edge, resulting in the partial blockage of holes, in the case of the large angle of attack.

High Pressure Turbine Deposition in Land Based Gas Turbines From Various Synfuels

2005 ◽  
Author(s):  
Jeffrey P. Bons ◽  
Jared Crosby ◽  
James E. Wammack ◽  
Brook I. Bentley ◽  
Thomas H. Fletcher
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Test Facility ◽  
Gas Temperature ◽  
High Pressure Turbine ◽  
Deposit Thickness ◽  
Barrier Coating ◽  
Power Turbine ◽  
Fuel Ash ◽  
Deposition Test

Ash deposits from four candidate power turbine synfuels were studied in an accelerated deposition test facility. The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes. A natural-gas combustor was seeded with finely-ground fuel ash particulate from four different fuels: straw, sawdust, coal, and petroleum coke. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.31 before impinging on a thermal barrier coating (TBC) target coupon at 1150°C. Post exposure analyses included surface topography, scanning electron microscopy, and x-ray spectroscopy. Due to significant differences in the chemical composition of the various fuel ash samples, deposit thickness and structure vary considerably for each fuel. Biomass products (e.g. sawdust and straw) are significantly less prone to deposition than coal and petcoke for the same particle loading conditions. In a test simulating one turbine operating year at a moderate particulate loading of 0.02 parts per million by weight, deposit thickness from coal and petcoke ash exceeded 1 mm and 2 mm respectively. These large deposits from coal and petcoke were found to detach readily from the turbine material with thermal cycling and handling. The smaller biomass deposit samples showed greater tenacity in adhering to the TBC surface. In all cases, corrosive elements (e.g. Na, K, V, Cl, S) were found to penetrate the TBC layer during the accelerated deposition test. Implications for the power generation goal of fuel flexibility are discussed.

THE EFFECT OF THERMAL BARRIER COATING SURFACE TEMPERATURE ON THE ADHESION BEHAVIOR OF CMAS DEPOSITS

2021 ◽  
pp. 1-14
Author(s):  
Robert A. Clark ◽  
Nicholas Plewacki ◽  
Pritheesh Gnanaselvam ◽  
Jeffrey P. Bons ◽  
Vaishak Viswanathan
Keyword(s):  
High Pressure ◽  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Back Side ◽  
Gas Temperature ◽  
Front Side ◽  
Barrier Coating ◽  
Inlet Conditions ◽  
Side Flow

Abstract The interaction of thermal barrier coating’s (TBC) surface temperature with CMAS (calcium magnesium aluminosilicate) like deposits in gas turbine hot flowpath hardware is investigated. Small Hastelloy X coupons were coated in TBC and then subjected to a thermal gradient via back-side impingement cooling and front-side impingement heating using the High Temperature Deposition Facility (HTDF) at The Ohio State University (OSU). TBC front-side surface temperatures were varied by changing a constant temperature back-side mass flow, while maintaining a constant hot-side gas temperature and jet velocity representative of modern commercial turbofan high-pressure turbine (HPT) inlet conditions (approximately 1600K and 200 m/s, or Mach 0.25). In this study, Arizona Road Dust (ARD) was utilized to mimic the behavior of CMAS attack on TBCs. Accelerated deposition tests were performed where approximately 1 gram of ARD was injected into the hot side flow while the TBC surface temperature was held at various points above the minimum observed deposition temperature. Surface deposition on the TBC coupons was evaluated using an infrared camera and a backside thermocouple. In addition, an Eulerian-Lagrangian solver was used to model the hot-side impinging jet AND deposition was predicted using the OSU Deposition model. These results can be used to improve physics-based deposition models by providing valuable data relative to CMAS deposition characteristics on TBC surfaces, which modern commercial turbofan high pressure turbines use almost exclusively.

The Effect of Particle Size and Film Cooling on Nozzle Guide Vane Deposition

2012 ◽  
Author(s):  
C. Bonilla ◽  
J. Webb ◽  
C. Clum ◽  
B. Casaday ◽  
E. Brewer ◽  
...  
Keyword(s):  
Particle Size ◽  
Film Cooling ◽  
Guide Vane ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Test Facility ◽  
Deposit Thickness ◽  
Nozzle Guide Vane ◽  
Effect Of Particle Size ◽  
Nozzle Guide

An accelerated deposition test facility is used to study the effect of particle size and film cooling on deposit roughness, spatial distribution and thickness. Tests were run at gas turbine representative inlet Mach numbers (0.08) and temperatures (1080°C). Deposits were created from a sub-bituminous coal fly ash with mass median diameters from 4 to 16 microns (Stokes numbers ranging from 0.1 to 1.9. Two CFM56-5B nozzle guide vane doublets comprising three full passages and two half passages of flow were utilized as the test articles. Tests were run with three levels of film cooling. The addition of film cooling to the vanes was shown to decrease deposit capture efficiency by as much as a factor of 3 and shift the primary location of deposit buildup to the leading edge coincident with an increased region of positive cooling backflow margin. Video taken during tests noted that film cooling holes with negative backflow margin were primary areas of deposit formation regardless of film cooling percentage. Stokes number was shown to have a marked effect on vane capture efficiency, with the largest Stokes number ash (St = 1.9) approximately 3 times as likely to stick to the vane as the smallest Stokes number ash (St = 0.1). Post test observations on deposit thickness were made using a coordinate measurement machine. Deposit thickness was noted to be reduced with decreasing Stokes number and increased film cooling percentage. Deposit surface roughness falls with particle size but is only weakly dependent on cooling level.

Independent Effects of Surface and Gas Temperature on Coal Flyash Deposition in Gas Turbines at Temperatures Up to 1400°C

2015 ◽  
Author(s):  
Robert Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Combined Cycle ◽  
Capture Efficiency ◽  
Threshold Temperature ◽  
Gas Temperature ◽  
Independent Effects

Deposition of coal flyash in gas turbines has been studied to support the concept of integrated gasification combined cycle (IGCC). Although particle filters are used in IGCC, small amounts of ash particles less than 5 μm diameter enter the gas turbine. Previous deposition experiments in the literature have been conducted at temperatures up to about 1288°C. However, few tests have been conducted that reveal the independent effects of gas and surface temperature, and most have been conducted at gas temperatures lower than 1400°C. The independent effects of gas and surface temperature on particle deposition in a gas turbine environment were measured using the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Gas temperatures were measured with a type K thermocouple and surface temperatures were measured with two-color pyrometry using the RGB signals from a camera. This facility was modified for testing at temperatures up to 1400°C. Subbituminous coal fly ash, with a mass mean diameter of 4 μm, was entrained in a hot gas flow at a Mach number of 0.25. A nickel base super alloy metal coupon 2.5 cm in diameter was held in this gas stream to simulate deposition in a gas turbine. The gas temperature (and hence particle temperature) governs the softening and viscosity of the particle, while the surface temperature governs the stickiness of the deposit. Two tests series were therefore conducted. The first series used backside cooling to hold the initial temperature of the deposition surface (Ts,i) constant at 1000°C while varying the gas temperature (Tg) from 1250°C – 1400°C. The second series held Tg constant at 1400°C while varying the initial Ts,i from 1050°C to 1200°C by varying the amount of backside cooling. Capture efficiency and surface roughness were calculated. Capture efficiency increased with increasing Tg. Capture efficiency also initially increased with Ts,i until a certain threshold temperature where capture efficiency began to decrease with increasing Ts,i.

High-Pressure Turbine Deposition in Land-Based Gas Turbines From Various Synfuels

2005 ◽  
Vol 129 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Jeffrey P. Bons ◽  
Jared Crosby ◽  
James E. Wammack ◽  
Brook I. Bentley ◽  
Thomas H. Fletcher
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Test Facility ◽  
Gas Temperature ◽  
High Pressure Turbine ◽  
Deposit Thickness ◽  
Barrier Coating ◽  
Power Turbine ◽  
Fuel Ash ◽  
Deposition Test

Ash deposits from four candidate power turbine synfuels were studied in an accelerated deposition test facility. The facility matches the gas temperature and velocity of modern first-stage high-pressure turbine vanes. A natural gas combustor was seeded with finely ground fuel ash particulate from four different fuels: straw, sawdust, coal, and petroleum coke. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.31 before impinging on a thermal barrier coating (TBC) target coupon at 1150°C. Postexposure analyses included surface topography, scanning electron microscopy, and x-ray spectroscopy. Due to significant differences in the chemical composition of the various fuel ash samples, deposit thickness and structure vary considerably for each fuel. Biomass products (e.g., sawdust and straw) are significantly less prone to deposition than coal and petcoke for the same particle loading conditions. In a test simulating one turbine operating year at a moderate particulate loading of 0.02 parts per million by weight, deposit thickness from coal and petcoke ash exceeded 1 and 2mm, respectively. These large deposits from coal and petcoke were found to detach readily from the turbine material with thermal cycling and handling. The smaller biomass deposit samples showed greater tenacity in adhering to the TBC surface. In all cases, corrosive elements (e.g., Na, K, V, Cl, S) were found to penetrate the TBC layer during the accelerated deposition test. Implications for the power generation goal of fuel flexibility are discussed.

The Effect of Particle Size Ratio on Porosity of a Particles Deposition Process

2016 ◽  
Vol 675-676 ◽  
pp. 647-650
Author(s):  
Reza Rendian Septiawan ◽  
Sparisoma Viridi ◽  
Suprijadi
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Particle Method ◽  
Deposition Process ◽  
Close Packing ◽  
Size Ratio ◽  
Random Close Packing ◽  
Packing Structure ◽  
Particle Size Ratio ◽  
Effect Of Particle Size

Porosity plays an important role on a particle deposition process which determines the strength of material. The structure of a material from deposition process can be viewed as a random close packed. References show that random close packing structure of uniform-sized particles gives a porosity of around 36%. In this work we simulate the deposition process using a particle method to study the effect of particle size ratio into a porosity of a material with the ratio of particles’ radius is ranged from 1:1 to 1:5. From the simulation we get an interesting result that shows the porosity is decreased when the size ratio is increased in range from 1:1 to 1:1.5 with its minimum porosity is 31.92% at ratio 1:1.5. Then as the ratio increases from 1:1.5 to 1:5, the porosity is also increasing.

The Effect of Particle Size and Film Cooling on Nozzle Guide Vane Deposition

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
C. Bonilla ◽  
J. Webb ◽  
C. Clum ◽  
B. Casaday ◽  
E. Brewer ◽  
...  
Keyword(s):  
Particle Size ◽  
Film Cooling ◽  
Guide Vane ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Test Facility ◽  
Deposit Thickness ◽  
Nozzle Guide Vane ◽  
Effect Of Particle Size ◽  
Nozzle Guide

An accelerated deposition test facility is used to study the effect of particle size and film cooling on deposit roughness, spatial distribution, and thickness. Tests were run at gas turbine representative inlet Mach numbers (0.08) and temperatures (1080 °C). Deposits were created from a subbituminous coal fly ash with mass median diameters from 4 to 16 micron (Stokes numbers ranging from 0.1 to 1.9). Two CFM56-5B nozzle guide vane doublets comprising three full passages and two half passages of flow were utilized as the test articles. Tests were run with three levels of film cooling. The addition of film cooling to the vanes was shown to decrease the deposit capture efficiency by as much as a factor of 3 and shift the primary location of deposit buildup to the leading edge, coincident with an increased region of positive cooling backflow margin. Video taken during the tests noted that film cooling holes with a negative backflow margin were primary areas of deposit formation, regardless of the film cooling percentage. The Stokes number was shown to have a marked effect on the vane capture efficiency, with the largest Stokes number ash (St = 1.9) approximately 3 times as likely to stick to the vane as the smallest Stokes number ash (St = 0.1). Posttest observations on the deposit thickness were made using a coordinate measurement machine. The deposit thickness was noted to be reduced with a decreasing Stokes number and an increased film cooling percentage. The deposit surface roughness falls with particle size but is only weakly dependent on the cooling level.

Sign in / Sign up

Export Citation Format

Share Document