Cold flow increasing structure for intake and exhaust and design method thereof

Abstract

The application relates to an increased cold flow structure for air intake and exhaust and a design method thereof. The purpose of increasing the cooling air flow is achieved by fixing the shrinkage rate and reducing the outlet section diameter of the exhaust pipe. The gas turbine realizes the rated working condition by the state of the exhaust pipe with the reduced outlet section area. The injection resistance is tested to make the total pressure difference value of the injection less than the design value. The exhaust resistance is tested to make the total pressure difference value of the exhaust less than the design value. When the injection air quantity meets the required value and the gas turbine efficiency is maximum, the structure is considered as the optimal exhaust pipe outlet necking section.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and in particular to a structure for increasing cold flow in intake and exhaust, and its design method. Background Technology

[0002] Gas turbines convert the chemical energy of fuel into kinetic energy through combustion. The combustion of fuel generates a large amount of heat, which is conducted to the surface of the gas turbine. At rated power, the surface temperature of the gas turbine can reach as high as 500°C, which in turn raises the temperature of the air inside the turbine enclosure through convection and radiation. When marine gas turbines are operating, exhaust jet ventilation is used to cool the enclosure environment, ensuring that all equipment inside the enclosure operates normally within the permissible ambient temperature range.

[0003] In practical use, the same type of gas turbine is used in different ship types, and different ship types are composed of different ejector and exhaust systems. Due to the influence of the actual ejector cooling air pipeline and exhaust pipeline resistance on the cooling air of the enclosure, when the gas turbine is installed in a ship type with a large ejector and exhaust system resistance, insufficient cooling air will be caused, which will result in the gas turbine electrical components overheating and losing their function. Summary of the Invention

[0004] In response to the shortcomings of the existing production technology, the applicant provides a structure and design method for increasing the cold air volume for intake and exhaust, which can meet the needs of ejector and exhaust systems of different ship types and provide sufficient cooling air volume.

[0005] The technical solution adopted in this invention is as follows:

[0006] A structure for increasing cold airflow in intake and exhaust systems, applied at the exhaust pipe outlet position of the intake and exhaust structure, employs an exhaust constriction section, which includes:

[0007] The constricted base is located at the outlet end of the exhaust pipe.

[0008] The constricted body is fastened to the constricted base; the diameter of the constricted body gradually decreases from the constricted base along the air outlet direction.

[0009] A gas turbine exhaust ejector ventilation structure with an increased cold flow structure for intake and exhaust includes a gas turbine body, which is installed at the A-type ejector and exhaust system, and an exhaust constriction section is installed at the outlet end of the exhaust port.

[0010] A design method for increasing the cold airflow of an intake and exhaust structure includes the following steps:

[0011] Step 1: Reduce the exit cross-sectional area of ​​the constricted body at a fixed reduction rate, and obtain several sets of exit cross-sectional area data.

[0012] Step 2: Detect the actual power output of the equipment corresponding to several sets of outlet cross-sectional area data until the rated operating condition is reached.

[0013] Step 3:

[0014] Test the ejector resistance; set the air inlet position of the air inlet pipe to section J1 and the air outlet position of the air inlet pipe to section J2, respectively, so that the total air pressure difference between section J1 and section J2 is less than the design value;

[0015] To test exhaust resistance, designate the exhaust pipe outlet end face as section P2 and the section near the intake position as section P1, ensuring the total airflow pressure difference between sections P1 and P2 is less than the design value.

[0016] The cross-sectional area channel obtained by meeting the above requirements is the nozzle size of the exhaust constriction section suitable for increasing the cooling air volume.

[0017] As a further improvement to the above technical solution:

[0018] The shrinkage rate in step one can be selected from 0.5% to 1.5%.

[0019] In step three of the test, several reduced-diameter models obtained according to the reduction ratio will be installed at the exhaust pipe outlet, and the equipment will be started at its rated power.

[0020] After the gas turbine outputs its rated power, the total pressure of the ejector and exhaust pipe of each constricted model is measured by probes. The total pressure difference between the two ends of the same pipe is compared with the design value. If it is lower than the design value, it is a qualified structure.

[0021] A verification method for a design-obtained structure for increasing cold airflow in the intake and exhaust systems includes the following steps:

[0022] Measure the ejector air flow rate and the equipment thermal efficiency. If the ejector air flow rate is greater than the design value, the necking size is acceptable. Under the premise that the ejector air flow rate is greater than the design value, the higher the equipment thermal efficiency, the better.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention features a simple structure, low failure rate, convenient operation, and intuitive results. By first obtaining a wide range of test nozzle diameter parameters, then sequentially detecting the total pressure difference between the ejector tube and the exhaust pipe, and comparing it with the design value, it can accurately determine whether the actual cooling air is sufficient and whether the cooling efficiency meets the requirements under the influence of the actual ejector cooling air pipeline and exhaust pipe resistance.

[0025] Compared to the conventional approach of directly reducing the nozzle size, this invention can effectively prevent a decrease in equipment efficiency. By comparing four sets of parameters in the design process, it can simultaneously meet both cooling and power requirements.

[0026] This invention has high applicability and can meet the adaptation requirements of ejector and exhaust systems of different ship types. It is less likely to cause problems such as insufficient cooling air and overheating loss of function of gas turbine electrical components when installed on ship types with ejector and exhaust systems with high resistance. It has broad application prospects. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating an example of the narrowed section of the present invention being applied to a gas turbine.

[0028] Figure 2 This is a schematic diagram of the exhaust constriction section structure of the present invention.

[0029] Figure 3 This is a flowchart illustrating the design concept of the present invention.

[0030] The components include: 1. Gas turbine body; 2. Injector tube; 3. Airflow channel; 4. Exhaust pipe; 5. Exhaust constriction section; 6. Power measurement device; 7. Packing body;

[0031] 201. Cooling inlet / outlet total pressure probe; 202. Louver; 203. Filter; 204. Ejector chamber;

[0032] 401. Total pressure probe at the smoke exhaust outlet;

[0033] 501. Reduced base; 502. Reduced body. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0035] like Figures 1-3 As shown, the intake and exhaust structure for increasing cold airflow in this embodiment is applied to the outlet position of the exhaust pipe 4 in the intake and exhaust structure, and adopts an exhaust constriction section 5. The exhaust constriction section 5 includes:

[0036] The constriction base 501 is located at the outlet end of the exhaust pipe 4.

[0037] The constriction body 502 is fastened to the constriction base 501; the diameter of the constriction body 502 gradually decreases from the constriction base 501 along the air outlet direction.

[0038] The intake and exhaust increased cold flow structure of this embodiment includes a gas turbine body 1, which is installed at the A-type ejector and exhaust system, and an exhaust constriction section 5 is installed at the outlet end of the exhaust port.

[0039] The design method for increasing the cold airflow structure for air intake and exhaust in this embodiment includes the following steps:

[0040] Step 1: Reduce the outlet cross-sectional area of ​​the constriction body 502 at a fixed reduction rate, and obtain several sets of outlet cross-sectional area data.

[0041] Step 2: Detect the actual power output of the equipment corresponding to several sets of outlet cross-sectional area data until the rated operating condition is reached.

[0042] Step 3:

[0043] Test the ejector resistance; set the air inlet position of the air inlet pipe to section J1 and the air outlet position of the air inlet pipe to section J2, respectively, so that the total air pressure difference between section J1 and section J2 is less than the design value;

[0044] To test the exhaust resistance, designate the exhaust pipe 4 outlet end face as section P2 and the section of exhaust pipe 4 near the intake position as section P1, ensuring that the total airflow pressure difference between sections P1 and P2 is less than the design value.

[0045] The cross-sectional area channel obtained by meeting the above steps is the nozzle size of the exhaust constriction section 5, which is suitable for increasing the cooling air volume.

[0046] The shrinkage rate in step one can be selected from 0.5% to 1.5%.

[0047] In step three of the test, several reduced-diameter models obtained according to the reduction ratio are installed at the outlet of exhaust pipe 4, and the equipment is simultaneously started at its rated power. The power measuring device 6 is used to measure the actual power output.

[0048] After the gas turbine outputs its rated power, the total pressure of the ejector pipe 2 and the exhaust pipe 4 is measured by probes in each constricted model. The total pressure difference between the two ends of the same pipe is compared with the design value. If it is lower than the design value, it is a qualified structure.

[0049] The verification method for the increased cold flow structure for intake and exhaust obtained by the above design method in this embodiment includes the following steps:

[0050] Measure the ejector air flow rate and the equipment thermal efficiency. If the ejector air flow rate is greater than the design value, the necking size is acceptable. Under the premise that the ejector air flow rate is greater than the design value, the higher the equipment thermal efficiency, the better.

[0051] The ejector air flow rate is obtained by measuring the total pressure and static pressure of the ejector pipe, and then the air velocity is calculated by using the air velocity and the inner diameter of the pipe.

[0052] The thermal efficiency of the equipment was obtained in accordance with the People's Republic of China shipbuilding industry standard "Data Processing Method for Tests on Thermodynamic Performance of Gas Turbines".

[0053] The specific design method of this invention and the resulting exhaust constriction section structure are as follows:

[0054] The purpose of this invention is to provide a highly versatile exhaust constriction section 5 that can be applied to various intake and exhaust systems. The working principle of the exhaust constriction section 5 is to reduce the size of the exhaust port while meeting the requirements for exhaust resistance, short-range resistance, and efficiency; under this premise, the nozzle is reduced in size to increase the amount of air ejected.

[0055] like Figure 1 As shown, as an application example, the exhaust constriction section 5 is used in a gas turbine operating condition. Figure 1 This is a schematic diagram of the exhaust jet ventilation structure for a gas turbine. In the diagram, the arrows inside the duct indicate the airflow direction, the arrows in airflow channel 3 indicate the cooling airflow direction, and the arrows in exhaust pipe 4 indicate the flue gasflow direction. Air enters airflow channel 3 from the duct, mixes with the cooling air, and then exits from exhaust pipe 4, mixing with the flue gas.

[0056] A gas turbine is installed inside the enclosure 7. The gas turbine outputs flue gas from its exhaust port, and a power measuring device 6 is connected to the gas turbine exhaust port.

[0057] The ejector tube 2 has an ejector chamber 204 at its inlet, and a filter 203 is installed at the inlet of the ejector chamber 204. A space with louvers 202 is provided to enclose the ejector chamber 204 for introducing outside air.

[0058] The exhaust constriction section 5 is installed at the outlet end of the exhaust pipe 4. The dimensions of the exhaust constriction section 5 must meet the requirements for exhaust resistance and intake resistance. Under the premise of meeting the resistance requirements, the dimension with the highest efficiency is the preferred dimension. In one embodiment of the present invention, the exhaust resistance and intake resistance are measured using an intake probe and an exhaust probe.

[0059] A cooling air inlet total pressure probe is installed at the air inlet location.

[0060] A smoke outlet total pressure probe 401 is installed at the outlet end of the exhaust pipe 4.

[0061] To facilitate subsequent sampling and positioning, the cross section of the air inlet of ejector tube 2 that introduces outside air is designated as section J1, the cross section at the junction of ejector tube 2 and housing 7 is designated as section J2, the flue gas outlet is designated as section P1, and the exhaust pipe 4 outlet is designated as section P2.

[0062] like Figure 2As shown, this invention provides an exhaust constriction section 5 at the outlet of the exhaust pipe 4. The exhaust constriction section 5 consists of a constriction base 501 connected to the exhaust pipe 4 and a constriction body 502 bolted to the constriction base 501. Lifting lugs are provided on the side wall of the constriction body 502. By reducing the outlet cross-sectional area of ​​the constriction body 502 by a 1% reduction rate, six sets of exhaust constriction sections 5 with different values ​​were obtained: a, b, c, d, e, and f, a total of six constriction models, with outlet circle diameters of 0.99m, 0.98m, 0.97m, 0.96m, and 0.95m, respectively.

[0063] Six constriction models, a, b, c, d, e, and f, are installed at the four outlets of the exhaust pipe, and the gas turbine is started simultaneously to generate power up to the rated operating condition.

[0064] After the gas turbine outputs its rated power, the total pressure of the two ejector pipes and four exhaust pipes is obtained by measuring different constriction models.

[0065] The total pressure P at the exhaust pipe outlet is measured using an exhaust pipe outlet total pressure probe. p1截面 1. Total pressure probe 1 measures the total pressure P at the exhaust outlet. p2截面 ; Cooling intake inlet total pressure probe measurement of cooling intake inlet total pressure P J1截面 The total pressure P at the cooling intake outlet is measured by a probe. J2截面 .

[0066] ejection resistance = P J2截面 -P J1截面 Smoke exhaust resistance = P p1截面 -P p2截面 .

[0067] The measurement results are shown in Table 1.

[0068]

[0069] Table 1

[0070] As shown in Table 1, the constriction models a, b, c, and d meet the requirements for ejection and exhaust resistance.

[0071] Table 2 shows the ejector air flow rate and thermal efficiency of the six gas turbine models (a, b, c, and d) when their actual power output reaches the rated operating condition.

[0072]

[0073] Table 2

[0074] Table 2 shows that models c and d meet the ejector airflow requirements, but the gas turbine thermal efficiency of model c is higher than that of model d. Therefore, model d is the optimal exhaust pipe outlet constriction section. The constriction section of model d is suitable for the cooling requirements of the gas turbine under this type A ejector and exhaust system.

[0075] This invention employs a method of first obtaining several dimensions to be tested, and then specifically measuring the pressure difference at a designated location. By comparing the total pressure of the ejector pipe and the exhaust pipe, it can determine whether the cooling air volume is sufficient. The structure is simple, and the screw-locking structure facilitates the testing and replacement of the constriction structure. The results obtained are intuitive and reliable, and it is especially suitable for determining and adjusting the cooling air volume of gas turbines.

[0076] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A design method for an intake and exhaust structure to increase cold airflow, characterized in that: The structure for increasing cold air flow in the intake and exhaust system is applied to the outlet position of the exhaust pipe (4) of the intake and exhaust structure. An exhaust constriction section (5) is adopted, which includes: The constricted base (501) is located at the outlet end of the exhaust pipe (4). A constriction body (502) is fastened to a constriction base (501); the diameter of the constriction body (502) gradually decreases from the constriction base (501) along the gas outlet direction; it also includes a gas turbine body (1), which is installed at the A-type ejector and exhaust system, and the exhaust constriction section (5) is installed at the outlet end of the exhaust port; the design method includes the following steps: Step 1: Reduce the outlet cross-sectional area of ​​the constriction body (502) at a fixed reduction rate, and obtain several sets of outlet cross-sectional area data. Step 2: Detect the actual power output of the equipment corresponding to several sets of outlet cross-sectional area data until the rated operating condition is reached. Step 3: Test the ejector resistance; set the air inlet position of the air inlet pipe to section J1 and the air outlet position of the air inlet pipe to section J2, respectively, so that the total air pressure difference between section J1 and section J2 is less than the design value; Test the exhaust resistance by designating the exhaust pipe (4) outlet end face as section P2 and the exhaust pipe (4) section near the intake position as section P1, ensuring that the total airflow pressure difference between sections P1 and P2 is less than the design value. The cross-sectional area channel obtained by meeting the above requirements is the nozzle size of the exhaust constriction section (5) suitable for increasing the cooling air volume.

2. The design method as described in claim 1, characterized in that: The shrinkage rate in step one can be selected from 0.5% to 1.5%.

3. The design method as described in claim 1, characterized in that: During the third step of the test, several reduced-mouth models obtained according to the reduction ratio will be installed at the outlet of the exhaust pipe (4) and the equipment will be started at its rated power.

4. The design method as described in claim 3, characterized in that: After the gas turbine outputs its rated power, the total pressure of the ejector pipe (2) and exhaust pipe (4) of each constricted model is measured by probe. The total pressure difference between the two ends of the same pipe is compared with the design value. If it is lower than the design value, it is a qualified structure.

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