CN-120720077-B - Big or small air film cooling hole type under big intercostal spacing of cross flow channel

Abstract

The invention belongs to the technical field of gas turbines, and provides a large-small air film cooling hole type under a large rib spacing of a cross flow channel, wherein a main flow channel is a flow direction channel, a cold air channel is a cross flow ribbed channel, each rib section comprises two air film holes, namely a rib front hole and a rib rear hole, each air film hole comprises a cold air inlet, a cylindrical hole section, an expansion section and an air film hole outlet, one end of the cylindrical hole is communicated with the air film hole inlet, the other end of the cylindrical hole is communicated with one end of the expansion section, the other end of the expansion section is communicated with the air film hole outlet, the air film hole inlet is connected with the cross flow ribbed channel, and the air film hole outlet is connected with the main flow channel.

Inventors

• ZHANG CHAO
• LI WEISHUO
• SHAO YAZHOU
• TONG ZHITING

Assignees

• 天津理工大学

Dates

Publication Date

20260512

Application Date

20250619

Claims (3)

1. 1. The large-small air film cooling hole type under the large rib spacing of the cross flow channel is characterized in that the main flow channel is a flow direction channel, the cold air channel is a cross flow ribbed channel, each rib section comprises two air film holes which are respectively a rib front hole and a rib rear hole, and each air film hole comprises a cold air inlet, a cylindrical hole section, an expansion section and an air film hole outlet; One end of the cylindrical hole is communicated with the air film hole inlet, the other end of the cylindrical hole is communicated with one end of the expansion section, the other end of the expansion section is communicated with the air film hole outlet, the air film hole inlet is connected with the cross flow ribbed channel, and the air film hole outlet is connected with the main flow channel; the rib front holes are atmosphere film holes, and the rib rear holes are small film holes; The length-diameter ratio L m /D of the cylinder Kong Duanchang degree L m of the air film hole and the aperture D of the cylinder hole meets the conditions that L m /D is less than or equal to 1.5 and less than or equal to 4, the spreading angle b lat is less than or equal to 4 degrees and less than or equal to 15 degrees, and the back inclination angle b fwd is less than or equal to 0 degree and less than or equal to 15 degrees; the air film holes close to the incoming flow side of the cross-flow cold air are rib rear holes, and the air film holes far away from the incoming flow side are rib front holes.
2. 2. A crossflow duct large intercostal space large size film cooling hole pattern as recited in claim 1 wherein the rib front hole has a cylindrical length to diameter ratio L m /D of 2.8, a splay angle β lat of 13.4 °, a back rake angle β fwd of 4.6 °, the rib rear hole has a cylindrical length to diameter ratio L m /D of 1.9, a splay angle β lat of 12.8 °, and a back rake angle β fwd of 3.0 °.
3. 3. A design method of a large and small air film cooling hole pattern under a large rib spacing of a cross flow channel is applied to the design method of the large and small air film cooling hole pattern under the large rib spacing of the cross flow channel in claim 1, and is characterized by comprising the steps of selecting a design variable range according to literature experience data, constructing an initial sample library for 25 groups of data by using a Latin hypercube sampling method, performing CFD calculation on the sample library, constructing a nonlinear proxy model between multiple inputs and multiple outputs by taking eta ave,M and Nu/Nu 0ave,M as optimization targets through a radial basis neural network, then performing multi-objective artificial bird nest optimization based on the proxy model to obtain a group of Pareto optimal solution set, comparing a numerical simulation calculation result with an optimization prediction result, judging whether the absolute value of an error of the numerical simulation calculation result and the optimization prediction result is less than 2%, and completing the optimization design, otherwise, putting the optimization design variable value and the calculation result into the sample library together, and training again until convergence deviation standard is met, and finally obtaining an optimal scheme by using a TOPSI method; η ave,M is the average air film cooling efficiency of the cooling wall surface under the working condition of the specified blowing ratio M; Nu/Nu 0ave,M is the average relative Nussel number of the cooling wall surface under the condition of the designated blowing ratio M.

Description

Big or small air film cooling hole type under big intercostal spacing of cross flow channel Technical Field The invention belongs to the technical field of gas turbines, and particularly relates to a large and small air film cooling hole type under a large rib spacing of a cross flow channel. Background The gas turbine is widely applied to the fields of ship power, energy power generation, power propulsion and the like as power mechanical equipment for driving turbine blades to rotate to do work by using high-temperature and high-pressure gas generated by combustion of natural gas, synthetic gas and other fuels. The efficiency and the single power of the gas turbine can be effectively improved by increasing the turbine inlet temperature, however, along with the continuous increase of the turbine inlet temperature, more and more serious tests are put forward for the safe operation of the gas turbine, so that corresponding measures must be taken to ensure that the blade temperature is lower than the allowable temperature of the material so as to ensure the safe operation of the turbine blade of the gas turbine. The film cooling technique plays an important role in the thermal protection of the hot end components of the gas turbine. The principle of air film cooling is that jet cool air is sprayed out from discrete air film holes, and interacts with the main flow to form a layer of air film layer formed by mixing the main flow and cool air and covered on the surface of the blade, so that the high-temperature main flow is isolated to cool the turbine blade. In the prior art of air film cooling, two or more air film holes with large rib spacing are taken as a whole to carry out hole type design adjustment to improve the air film cooling efficiency, but in the practical application process, the air film cooling performance of the front hole and the rear hole of the rib in the large rib spacing is different, and the cooling efficiency of a single air film hole is obviously reduced after the adjustment design. Therefore, the film hole patterns with large rib pitches are respectively adjusted and designed to improve the film cooling efficiency. The invention provides a large-small air film cooling hole type under a large rib spacing of a cross flow channel, which is used for improving the cooling performance of an integral air film hole. Disclosure of Invention The invention provides a large and small air film cooling hole type under a large rib spacing of a cross flow channel, which solves the problems in the prior art, and adopts the following technical scheme: The main flow channel is a flow direction channel, the cold flow channel is a cross flow ribbed channel, each rib section comprises two air film holes which are respectively a rib front hole and a rib rear hole, and each air film hole comprises a cold flow inlet, a cylindrical hole section, an expansion section and an air film hole outlet. One end of the cylindrical hole is communicated with the air film hole inlet, the other end of the cylindrical hole is communicated with one end of the expansion section, the other end of the expansion section is communicated with the air film hole outlet, the air film hole inlet is connected with the cross flow ribbed channel, and the air film hole outlet is connected with the main flow channel. Further, the rib front hole and the rib rear hole are respectively a large and a small air film hole, the air film hole close to the incoming flow side of the cross flow cold air is the rib rear hole, and the air film hole far away from the incoming flow side is the rib front hole. Further, the length-diameter ratio L m/D of the cylindrical section of the rib front hole is 2.8, the spreading angle beta lat is 13.4 degrees, the back inclination angle beta fwd is 4.6 degrees, the length-diameter ratio L m/D of the cylindrical section of the rib rear hole is 1.9, the spreading angle beta lat is 12.8 degrees, the back inclination angle beta fwd is 3 degrees, the rib front hole is a large air film hole, and the rib rear hole is a small air film hole. Further, the length-diameter ratio L m/D of the cylinder Kong Duanchang degrees L m of the air film hole and the aperture D of the cylinder hole meets 1.5-L m/D-4, the spreading angle is 4-15 degrees beta lat -15 degrees, and the back inclination angle is 0- fwd -15 degrees. A design method for a large-size air film cooling hole pattern under a large rib spacing of a cross flow channel comprises the steps of selecting a design variable range according to literature experience data, constructing an initial sample library by using a Latin hypercube sampling method, performing CFD calculation on the sample library, constructing a nonlinear agent model between multiple inputs and multiple outputs through a radial basis neural network by taking eta ave,M and Nu/Nu 0ave,M as optimization targets, then performing multi-target artificial humming optimization based on the agent model to obtain a g