Jet-into-Crossflow Boundary-Layer Control: Innovation in Gas Turbine Blade Cooling

Javadi, Khodayar; Taeibi-Rahni, M.; Darbandi, Masood

doi:10.2514/1.28770

Cited by 29 publications

(8 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The anti-vortex hole technique made use of a primary cylindrical cooling hole with anti-vortex holes originating along its development length [19]. In agreement with the work of Javadi et al [17,18], both Dhungel [19] and Heidmann [20] found that the addition of these secondary holes improved effectiveness by reducing the impact of the primary vortex pair. Further, Heidmann [20] performed a parametric study to determine the optimum position of the secondary holes.…”

Section: Multi-jet Arrangementssupporting

confidence: 67%

See 1 more Smart Citation

A Numerical Study On Active Film Cooling Flow Control Through The Use Of Sister Holes

Ely¹

2021

Preprint

View full text Add to dashboard Cite

The research contained herein studied the effect of sister holes on film cooling. This novel technique surrounds a primary injection hole by two or four smaller sister holes to actively maintain flow adhesion along the surface of the blade. A numerical evaluation using the realizable κ-ε turbulence model led to the determination that the use of sister holes significantly improves adiabatic effectiveness by countering the primary vertical flow structure. Research was performed to determine the optimal hole configuration, arriving at the conclusion that placing sister holes slightly downstream of the primary injection hole improves the near-hole effectiveness, while placing sister holes slightly upstream of the primary hole improves downstream effectiveness. Similar results were found in evaluating both long and short hole geometries with a significantly less coherent flow field arising form the short hole study. However, on the whole, the sister hole approach to film cooling was found to offer viable improvements over standard cooling regimes.

show abstract

Section: Multi-jet Arrangementssupporting

confidence: 67%

“…More recent research by the group of Javadi et. al [18] attributed the performance gains of the triple jet technique to the additional CRVPs generated by the bounding jets. Their counterrotating nature effectively minimized the primary vortex structure to maintain flow adhesion and increase lateral spreading [18].…”

Section: Multi-jet Arrangementsmentioning

confidence: 99%

A Numerical Study On Active Film Cooling Flow Control Through The Use Of Sister Holes

Ely¹

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Moreover, when two sister holes are placed slightly downstream of the primary hole ( Figure 2b), their jets generate an anti-CRVP, as illustrated in Figure 3b. Therefore, film-cooling effectiveness is increased by establishing vortex interactions between the jets and by reducing the intensity of the main CRVP [9][10][11][12]. The boundary conditions in each computational domain are specified in Table 1.…”

Section: Geometry and Boundary Conditionsmentioning

confidence: 99%

Large Eddy Simulation of Film Cooling with Triple Holes: Injectant Behavior and Adiabatic Film-Cooling Effectiveness

Baek

Ahn

2020

Processes

View full text Add to dashboard Cite

This study investigated the effect of adding two sister holes placed downstream the main hole on film cooling by employing large eddy simulation. Here, film-cooling flow fields from a triple-hole system inclined by 35° to a flat plate at blowing ratios of M = 0.5 and unity were simulated. Each sister hole supplies a cooling fluid at a flow rate that is a quarter of that for the main hole. The simulations were conducted using the Smagorinsky–Lilly model as the subgrid-scale model, and the results were compared with those for a single-hole system for the same amount of total cooling air and same cross-sectional area of the holes. Relative to the single-hole system, the spanwise-averaged film-cooling effectiveness in the triple-hole configuration at M = 1.0 increased by as much as 345%. The subsequent proper orthogonal decomposition analysis showed that the kinetic energy of a counter-rotating vortex pair in the triple-hole system dropped by 30–40% relative to that of the single-hole system. This indicates that the additional sister holes promoted the suppression of the mixing of the coolant jet with the mainstream flow, thus keeping the temperature of the latter low. Cross-sectional views of the root-mean-square temperature contours were also analyzed; with the results confirming that the effect of the sister holes on the jet trajectory greatly contributes in promoting film-cooling effectiveness as compared to the effect of the reduced mixing.

show abstract

“…They also reported that manufacturing triple cylindrical holes was more economical than manufacturing holes with other shapes. Using square sister holes, Javadi et al [5] controlled the vortex interactions between injectant and main flow at the blowing ratio, M of 0.5. They numerically found that two sister holes reduced the mixing between the coolant injectant and the crossflow, thereby increasing η. Ely et al [6] numerically investigated the increase in η after forming two sister holes [3].…”

Section: Introductionmentioning

confidence: 99%

Effects of Bulk Flow Pulsations on Film Cooling with Two Sister Holes

Baek

Ahn

2021

Applied Sciences

View full text Add to dashboard Cite

In a triple-hole system comprising a primary hole and two sister holes, when the sister holes are positioned slightly downstream of the main hole under steady flow conditions, their jets generate an anti-counter-rotating vortex pair. Vortex interactions between the jets increase the effectiveness of adiabatic film cooling. In this study, a series of large-eddy simulations were conducted to understand how pulsations in the main flow affect film cooling in a triple hole. To understand the effects of pulsations on film cooling performance is important for better cooling design of the gas turbine engines. The numerical simulations were carried out on a flat plate geometry with a triple cylindrical hole system at 35° injection angle. The pulsations were approximately sinusoidal, and their effect on film cooling was investigated at several frequencies (2, 16, and 32 Hz) and Strouhal numbers (Sr = 0.1005, 0.8043, and 1.6085) at an average blowing ratio of 0.5. The results for the triple-hole system were compared with those for a single hole for the same amount of cooling air and the same cross-sectional area of the holes. Increasing the Strouhal number of the main flow decreased η in both systems. However, at each Strouhal number, η was higher in the triple hole. Furthermore, the triple-hole system was found to be better for film cooling than a single-hole system for higher values of the pulsation Strouhal number. Contours of time-averaged film cooling effectiveness and dimensionless temperature, instantaneous film cooling effectiveness contours on a test plate, mean velocity magnitude contours in the hole, and Q-contours for the triple holes under the application of pulsations to the flow were investigated.

show abstract

Jet-into-Crossflow Boundary-Layer Control: Innovation in Gas Turbine Blade Cooling

Cited by 29 publications

References 76 publications

A Numerical Study On Active Film Cooling Flow Control Through The Use Of Sister Holes

A Numerical Study On Active Film Cooling Flow Control Through The Use Of Sister Holes

Large Eddy Simulation of Film Cooling with Triple Holes: Injectant Behavior and Adiabatic Film-Cooling Effectiveness

Effects of Bulk Flow Pulsations on Film Cooling with Two Sister Holes

Contact Info

Product

Resources

About