CN110145371A - A target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs - Google Patents

Abstract

The invention discloses a target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs. An array structure is formed by arranging a number of target plate conical bosses and spanwise discontinuous straight ribs on the impact target plate. The spanwise discontinuous straight ribs are located in the middle of the conical bosses of the target plate, and are arranged repeatedly at equal intervals along the spanwise direction of the target plate. The conical bosses and spanwise discontinuous straight ribs are used for flow diversion to enhance the impact heat transfer capacity. In the area of low flow velocity on the surface of the target plate, the conical boss on the impact target plate is used to replace the low-velocity fluid, which has a good diversion effect on the impact jet, reduces the pressure loss caused by the direct impact of the jet on the flat target plate, and at the same time reduces the impact distance and is extremely Greatly increases the heat transfer coefficient on the conical boss. The spanwise intermittent straight ribs on the impact target plate can weaken the cross-flow effect generated when the array impacts, and enhance the disturbance of the two impact flows in the interface area, thereby effectively improving the impact heat transfer effect, reducing flow loss and strengthening impact heat transfer the goal of.

Description

A target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs

technical field

The invention relates to a cooling technology for strengthening array impingement heat exchange and reducing pressure loss, in particular to a cooling target plate structure for high-temperature components used in the chord region of aeroengine guide blades and electronic devices.

technical background

The cooling technology of gas turbine blades includes internal cooling, external cooling and composite cooling technology, in which internal cooling includes spoiler cooling at the trailing edge of the blade, turbulent cooling of the ribbed serpentine channel in the middle of the blade, and cooling of the midchord and leading edge. Impingement cooling and swirl cooling in the leading edge of the blade have been developed in recent years. Impingement cooling is a cooling method in which the cooling medium is sprayed to the surface of the high-temperature parts of the turbine in the form of a jet to take away heat and achieve the purpose of cooling. Because the flow boundary layer formed by impingement cooling is very thin, the heat transfer coefficient is several times higher than that of conventional convective heat transfer, so impingement cooling can most effectively improve the local heat transfer coefficient among all enhanced heat transfer technologies, so Impingement cooling is widely used in high temperature components of modern aeroengines and gas turbines. Especially at the leading edge of the blade where the turbine heat load is the highest, impingement convection cooling is usually used for cooling protection. Impingement cooling is also applied to the blade basin and blade back of the turbine blade to cool and dissipate heat. The cooling medium directly impacts the surface to be cooled, the outlet air velocity is fast, the process is very short, and a thin boundary layer is formed near the stagnation point, and the heat transfer efficiency is very high. high.

In Peter Hrycak. Heat transfer from impinging jets to a flat plate with conical and ring protuberances, International Journal of Heat and Mass Transfer, 1984, Vol.27(11), pp.2145-2154, conical and ring-shaped protrusions were studied For impact cooling, the experimental Reynolds numbers are 14000, 26000, 57000 and 67000, and the diameters of the circular nozzles are 3.18mm, 6.52mm and 9.52mm. The results show that the heat transfer at the stagnation point is significantly enhanced, and the ring-shaped protrusions reduce the local heat flux to a certain extent, but the average heat transfer of the entire target plate is relatively less affected by the protrusions, indicating that the structure is very effective for the rapid exchange of heat. Hot spots are more beneficial to cool down. Annerfeldt and Persson et al. in Experimental investigation of impingement cooling with turbulators or surface enlarging elements, ASME paper, 2001, No. 2001-GT-0149; in the experimental investigation of impingement cooling with turbulators or surface enlarging elements, ASME paper, 2001, No. 2001-GT-0149; by arranging rough elements of different geometric shapes to increase the heat transfer surface area and enhance turbulence degree, thereby achieving the possibility of enhancing the impingement cooling performance. The different geometries tested included triangle, cylinder, airfoil and short rib, and the impact holes were arranged in a forked row. The results show that the Nusselt number of the whole target plate of these structures is increased by 0 to 30% compared with the flat plate structure, and this trend decreases with the increase of impact spacing and Reynolds number. ChangminSon and PerterIreland proposed in An investigation of the application of roughness elements to enhanceheat transfer in an impingement cooling system, ASME paper, 2005, No.2005-GT-68504. Arranging spoiler elements on the target surface to enhance impingement cooling Influence, two simple shapes of cylinder and rhombus were chosen for the experimental spoiler element, and the heights were 30%, 50% and 70% of the height of the impingement channel, respectively. The results show that regions of low heat transfer coefficient between jets can be covered using rough elements, increasing the overall heat transfer capacity of impingement cooling by 22% to 35% at the expense of little additional pressure loss. Robin Brakmann and Lingling Chen studied in Bernhard Weigandand Michael Crawford. Experimental and Numerical Heat Transfer Investigation of an Impinging Jet Array on a Target Plate Roughened by Cubic Micro PinFins. Journal of Turbomachinery,2016,138(11):111010-1-9. The influence of micro-cubic ribs on the impingement heat transfer and pressure loss characteristics of the array was studied. The impact hole plate is arranged with 9×9 impact holes, and the side length of the tiny cubic ribs is 0.22 times the impact hole diameter. The existence of the micro ribs increases the heat exchange area of the target plate by 150%. The ratio of the distance between the impact orifice plate and the hole diameter is 3 to 5, and the Reynolds number is 15000, 25000, 35000. The results show that compared with the flat target plate, the heat flux of the target plate with tiny cubic ribs increases to about 134-142%, but the Nusselt number decreases slightly, and the additional pressure loss caused by the tiny cubic ribs Not more than 14%.

Contents of the invention

In order to avoid the deficiencies in the prior art and improve the heat transfer efficiency of impingement cooling in the chord region of the turbine blade, the present invention proposes a target plate structure with a combination of conical bosses and spanwise intermittent straight ribs; the target plate structure can The heat transfer is greatly enhanced without causing a large pressure loss, and the turbine blades are effectively cooled and protected.

The idea of the present invention is: when the impinging jet impacts the plane target plate, the low-velocity fluid is replaced by the conical boss on the impact target plate in the lower flow velocity area on the target plate surface, and the existence of the conical boss increases the heat transfer area and increases the heat exchange rate. Heat: The spanwise discontinuous straight ribs on the impact target plate can weaken the cross-flow effect generated during the impact of the array, and enhance the disturbance of the two impact flows in the interface area, thereby effectively improving the impact heat transfer effect, so as to reduce flow loss and strengthen The purpose of impact heat transfer.

The technical solution adopted by the present invention to solve its technical problems is: comprising impact plate, impact target plate, array impact holes, target plate spanwise discontinuous straight rib and target plate conical boss, it is characterized in that a number of targets are arranged on the impact target plate The conical bosses of the target plate and the spanwise discontinuous straight ribs of the target plate are combined to form an array structure. The spanwise discontinuous straight ribs of the target plate are located in the middle of the conical bosses of the target plate and are arranged repeatedly at equal intervals along the spanwise direction of the target plate. The conical bosses of the target plate and the spanwise discontinuous straight ribs of the target plate are used to enhance the impact heat transfer capacity; among them, the diameter D ₁ of the upper surface of the conical boss on the impact target plate is 0.571d, the diameter D ₂ of the lower surface of the conical boss is 4d, and the height of the conical boss is h ₁ is 0.714d, the radius R ₁ of the generatrix of the conical boss surface is 2.414d; the width A of the upper surface of the spanwise intermittent straight rib is 0.143d, the width B of the lower surface of the spanwise intermittent The length L is 6d, the height h ₂ of the spanwise discontinuous straight rib is 0.3H, 0.5H or 0.7H, and the radius R ₂ of the spanwise discontinuous straight rib curved surface ranges from 0.629 to 2.5d.

The array impact holes are arranged in a straight row, the diameter of the array impact holes is d, the distance between the impact plate and the impact target plate is 2d, the distance between the impact holes in the span direction and the flow direction is 10d, the spanwise intermittent straight ribs of the target plate, and the conical boss of the target plate Both are proportional to the impact hole diameter.

Beneficial effect

The present invention proposes a target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs. By arranging a number of target plate conical bosses and spanwise discontinuous straight ribs on the impact target plate, an array structure is formed. The spanwise discontinuous straight ribs are located in the middle of the conical bosses of the target plate, and are arranged repeatedly at equal intervals along the spanwise direction of the target plate. The conical bosses and spanwise discontinuous straight ribs are used for flow diversion to enhance the impact heat transfer capacity. In the area of low flow velocity on the surface of the target plate, the conical boss on the impact target plate is used to replace the low-velocity fluid, which has a good diversion effect on the impact jet, reduces the pressure loss caused by the direct impact of the jet on the flat target plate, and at the same time reduces the impact distance and is extremely Greatly increases the heat transfer coefficient on the conical boss. The function of the spanwise intermittent straight ribs is mainly to weaken the influence of the cross flow and enhance the disturbance. When the Reynolds number is large, the improvement of the heat transfer coefficient is particularly obvious at the downstream of the impacting target plate, but due to the existence of the spanwise ribs, the flow area Reduced, so the flow resistance will increase, but the magnitude is small. And the presence of the ribs increases the heat exchange area, further improving the heat exchange effect.

Description of drawings

A target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs of the present invention will be further described in detail below in conjunction with the drawings and embodiments.

Fig. 1 is a structural schematic diagram of a target plate with a combination of conical bosses and spanwise discontinuous straight ribs according to the present invention.

Fig. 2 is a cross-sectional view of the structure of the target plate with the combination of conical bosses and spanwise discontinuous straight ribs according to the present invention.

Fig. 3 is a top view of the structure of the target plate with the combination of conical bosses and spanwise discontinuous straight ribs according to the present invention.

in the picture

1. Impact plate 2. Array impact holes 3. Impact target plate 4. Target plate spanwise discontinuous straight rib 5. Target plate conical boss

d is the diameter of the array impact holes X is the distance between the transverse impact holes Y is the distance between the longitudinal impact holes

H is the distance between the impact plate and the impact target plate D ₁ is the diameter of the upper surface of the conical boss on the impact target plate

D ₂ is the diameter of the lower surface of the conical boss h ₁ is the height of the conical boss R ₁ is the radius of the generatrix of the curved surface of the conical boss

A is the upper surface width of spanwise discontinuous straight rib

B is the width of the lower surface of the spanwise intermittent straight rib

L is the length of spanwise intermittent straight rib

h ₂ is the height of spanwise intermittent straight rib

R ₂ is the radius of the generatrix of the spanwise discontinuous straight rib surface

Detailed ways

This embodiment is a target plate structure with a combination of conical bosses and spanwise discontinuous straight ribs. By arranging the conical boss structure on the array impingement airless film target plate, the flow diversion effect is carried out to strengthen the heat exchange in the stagnation zone; the spanwise discontinuous straight rib is arranged in the middle of the two conical bosses, which can reduce the influence of cross flow, Enhancing the disturbance effect can enhance the heat transfer capacity downstream of the target plate.

Referring to Fig. 1, Fig. 2 and Fig. 3, the present embodiment has a target plate structure combined with conical bosses and spanwise discontinuous straight ribs, which consists of impact plate 1, impact target plate 3, array impact holes 2, target plate spanwise discontinuous It consists of straight ribs 4 and conical bosses 5 of the target plate; among them, a number of conical bosses 5 of the target plate and intermittent straight ribs 4 in the span direction of the target plate are arranged on the impact target plate 3 to form an array structure, and the intermittent straight ribs 4 of the target plate in the span direction Located in the middle of the conical bosses 5 of the target plate, and arranged repeatedly at equal intervals along the span direction of the target plate, the conical bosses 5 of the target plate and the intermittent straight ribs 4 in the span direction of the target plate are used to enhance the impact heat transfer capacity. Among them, the diameter D1 of the upper surface of the conical boss on the impact target plate is _0.571d , the diameter D2 of the lower surface of the conical boss is 4d, the height _{h1 of} the conical boss is 0.714d, and the radius R1 _of the generatrix of the curved surface of the conical boss is 2.414d. The width A of the upper surface of the spanwise discontinuous straight rib is 0.143d, the width B of the lower surface of the spanwise discontinuous straight rib is 1d, the length L of the spanwise discontinuous straight rib is 6d, and the height h2 of the spanwise discontinuous straight rib is 0.3H, _0.5 H or 0.7H, the value range of the generatrix radius R ₂ of the spanwise discontinuous straight rib surface is 0.629～2.5d. The arrangement of the array impact holes 2 is arranged in a row, the diameter of the array impact holes is d, the distance between the impact plate 1 and the impact target plate 3 is 2d, the distance between the impact holes in the span direction and the flow direction is 10d, the conical boss of the target plate 5, the target plate spread The size of the discontinuous straight ribs 4 is proportional to the diameter of the impact hole.

In this embodiment, numerical simulation and experimental methods are used for verification, and a 6×3 hole impact model is used. The specific parameters are: the diameter d of the array impact holes is 7mm, the horizontal and vertical spacing of the array impact holes are 70mm, and the impact spacing It is 14mm, and the Reynolds number Re is 25000. When analyzing the results, the Nusselt number Nu is used to measure the heat transfer effect, and the flow coefficient Cd is used to measure the pressure loss.

Embodiment one

This embodiment is a simplified simulation of the impingement cooling structure inside the chord region of a certain type of turbine guide vane. The simplified model is a 6×3 hole array impingement cooling model, the array impingement hole diameter d is 7mm, the spanwise and flow direction impingement hole intervals are both 10d, the impingement interval is 2d, and the Reynolds number Re is 25000. The diameter D1 of the upper surface of the conical boss on the impact target plate is _0.571d , the diameter D2 of the lower surface of the conical boss is 4d, the height of the conical boss _h1 is _0.714d , and the radius of the generatrix of the curved surface of the conical boss R ₁ is 2.414d. The width A of the upper surface of the spanwise discontinuous straight rib is 0.143d, the width B of the lower surface of the spanwise discontinuous straight rib is 1d, the length L of the spanwise discontinuous straight rib is 6d, and the height h2 of the _spanwise discontinuous straight rib is 0.3H. The radius R ₂ of the generatrix to the discontinuous straight rib surface is 0.629d.

Embodiment two

This embodiment is a simplified simulation of the impingement cooling structure inside the chord region of a certain type of turbine guide vane. The simplified model is a 6×3 hole array impingement cooling model. The diameter d of the array impingement holes is 7mm, the distance between the impingement holes in the span direction and the flow direction is 10d, the impact distance is 2d, and the Reynolds number Re is 25000. The diameter D1 of the upper surface of the conical boss on the impact target plate is _0.571d , the diameter D2 of the lower surface of the conical boss is 4d, the height of the conical boss _h1 is _0.714d , and the radius of the generatrix of the curved surface of the conical boss R ₁ is 2.414d. The width A of the upper surface of the spanwise discontinuous straight rib is 0.143d, the width B of the lower surface of the spanwise discontinuous straight rib is 1d, the length L of the spanwise discontinuous straight rib is 6d, and the height h2 of the _spanwise discontinuous straight rib is 0.5H. The radius R ₂ of the generatrix to the discontinuous straight rib surface is 1.386d.

Embodiment three

This embodiment is a simplified simulation of the impingement cooling structure inside the chord region of a certain type of turbine guide vane. The simplified model is a 6×3 hole array impingement cooling model. The diameter d of the array impingement holes is 7mm, the distance between the impingement holes in the span direction and the flow direction is 10d, the impact distance is 2d, and the Reynolds number Re is 25000. The diameter D ₁ of the upper surface of the conical boss on the impact target plate is 0.571d, the diameter D ₂ of the lower surface of the conical boss is 4d, the height h ₁ of the conical boss is 0.714d, and the radius of the generatrix of the curved surface of the conical boss R ₁ is 2.414d; the width A of the upper surface of the spanwise discontinuous straight rib is 0.143d, the width B of the lower surface of the spanwise discontinuous straight rib is 1d, the length L of the spanwise discontinuous straight rib is 6d, and the height h2 of the _spanwise discontinuous straight rib is 0.7H, the radius R ₂ of the generatrix of the spanwise discontinuous straight rib surface is 2.5d.

In the above three embodiments, the impact heat transfer effect mainly depends on the impact heat transfer temperature, the heat transfer area and the heat exchange intensity between the impact fluid and the impact target plate. During positive impact heat transfer, the flow direction of the impinging jet will immediately turn to 90 degrees after impacting the target plate, and flow along the wall surface, and the boundary layer will form and develop from the center of the impact area. Near the center of impact, the surface heat transfer coefficient is very high because the boundary layer is in the coverage area of the jet cross section, or is further thinned by the impact and extrusion of the jet. When the array impacts, the impact fluid between the holes will produce a cross-flow effect, which will weaken the impact heat transfer effect.

Claims (2)

1. a kind of with conical boss and the target plate structure opened up to the straight rib combination of interruption, including shock plate, impact target plate, array punching Hit hole, target plate is opened up to the straight rib of interruption and target plate conical boss, it is characterised in that: it is convex to lay several target plate circular cones on impact target plate Platform and target plate are opened up to straight rib is interrupted, and array structure is combined into, and target plate is opened up to be located among target plate conical boss to the straight rib of interruption, and edge Target plate is opened up to be repeated to arrange to equidistant, and target plate conical boss and target plate are opened up and be used to enhance impingement heat transfer ability to the straight rib of interruption；Its In, impact conical boss upper surface diameter D on target plate₁For 0.571d, conical boss lower surface diameter D₂For 4d, conical boss Height h₁For 0.714d, the generatrix radius R of conical boss curved surface₁For 2.414d；It opens up to the straight rib upper surface width A of interruption and is 0.143d, opening up to straight rib lower surface width B is interrupted is 1d, and opening up to the length L for being interrupted straight rib is 6d, is opened up to the height for being interrupted straight rib h₂For 0.3H, 0.5H or 0.7H, open up to the generatrix radius R for being interrupted straight rib curved surface₂Value range is 0.629~2.5d.

2. according to claim 1 have conical boss and open up to the target plate structure for being interrupted straight rib combination, it is characterised in that: The cloth in array impact hole is set as in-line arrangement, and array impact bore dia is d, and shock plate and impact target plate spacing are 2d, open up to flow direction Impact pitch of holes is 10d, and target plate is opened up proportional with impact aperture to the straight rib of interruption, target plate conical boss.