Quasi-critical zone improvement method based on multi-mode cooperative methane regeneration cooling and engine

Abstract

The invention relates to the technical field of airspace engine cooling, discloses a multi-mode collaborative methane regenerative cooling quasi-critical zone improvement method and an engine, and is applied to a regenerative cooling channel of a thrust chamber of an airspace engine. The method comprises the following steps: avoiding a methane quasi-critical heat transfer deterioration area through temperature anomaly identification and trend prediction and multi-mode cooperative temperature regulation and control: setting a dynamic threshold according to the working condition of an engine, and triggering heat transfer deterioration early warning through space and time double indexes; then three adjusting modes of temperature preposition, flow preposition and pressure active motion are matched according to the early warning triggering condition, so that the methane coolant avoids a quasi-critical heat transfer deterioration area; the problem that the cooling performance is reduced due to heat transfer deterioration of methane in a quasi-critical zone is solved, the cooling capacity of a cooling medium is efficiently utilized, regulation and control are automatic, response is fast, precision is high, the operation efficiency and reliability of a regenerative cooling system are effectively improved, and the safety of the wall face of a thrust chamber is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of aerospace engine cooling technology, specifically to a method for improving the quasi-critical region of methane regeneration cooling based on multi-mode synergistic cooling and an engine. Background Technology

[0002] Regenerative cooling is the most mainstream cooling method for the thrust chamber of liquid rocket engines. Its core principle is to process cooling channels on the outer wall of the engine combustion chamber. Before being injected into the combustion chamber, the fuel flows through these channels. Through convective heat exchange between the fuel and the channel wall, the heat transferred from the high-temperature combustion gas to the wall is carried away. This not only achieves cooling and protection of the thrust chamber wall, but also preheats the fuel, improving the fuel's energy utilization rate. It is a cooling method that takes into account both cooling effect and energy utilization.

[0003] In recent years, liquid methane has become a popular propellant in the aerospace field due to its advantages such as clean combustion, low carbon buildup, high density, small storage tank volume, and low cost. Compared with traditional kerosene and liquid hydrogen, it has significant comprehensive advantages and has been adopted by companies such as SpaceX, Blue Origin, and LandSpace in their liquid oxygen-methane propellant solutions for next-generation rocket engines. In aerospace engines using liquid methane as fuel, methane simultaneously serves as both a coolant and fuel. Within the regenerative cooling channel, it operates under supercritical pressure, and its temperature gradually increases from the low inlet temperature, undergoing a complete thermodynamic state change process from cold state to quasi-critical state to supercritical state.

[0004] The quasi-critical region of a fluid under supercritical pressure is a temperature range in which physical properties undergo drastic changes. For methane, the critical pressure is approximately 4.6 MPa and the critical temperature is approximately -82°C. Within the quasi-critical region, methane's physical properties exhibit a series of anomalous changes: its specific heat capacity first rises sharply to a peak and then drops rapidly, causing its heat absorption capacity to suddenly decrease after exceeding the peak; its density decreases avalanche-like with increasing temperature, triggering fluid acceleration and altering the flow boundary layer, further weakening the heat transfer effect; thermal conductivity and viscosity also exhibit extreme values ​​or inflection points, affecting flow resistance and the efficiency of heat transfer from the wall to the fluid core. These drastic changes in physical properties directly lead to significant heat transfer deterioration of methane in the quasi-critical region, manifested as a sharp drop in heat transfer coefficient and a rapid rise in thrust chamber wall temperature. If not effectively addressed, this will seriously threaten the structural safety of the thrust chamber wall, easily causing combustion gas erosion damage, rendering the engine unusable, and becoming a core technical bottleneck restricting the reliable operation of the regenerative cooling system of a liquid oxygen-methane engine.

[0005] To address the heat transfer issues in the regenerative cooling channels of aerospace engines, existing technologies primarily employ two conventional methods: first, increasing the flow rate of methane coolant to compensate for the total cooling load, attempting to alleviate wall temperature rise by increasing cooling input; second, increasing the wall thickness of the regenerative cooling thermal structure to provide safety redundancy and prevent wall damage due to high-temperature ablation. However, both methods have significant technical shortcomings, offering only passive solutions and failing to fundamentally address the heat transfer deterioration problem in the quasi-critical region of methane: increasing the flow rate does not consider avoiding the heat transfer deterioration zone, resulting in low cooling efficiency and interfering with the precise matching of engine fuel supply and demand, affecting normal engine operation; increasing the wall thickness of the thermal structure sacrifices the engine's lightweight design and increases manufacturing costs, without improving the flow and heat transfer characteristics of the methane coolant itself, failing to solve the core problem of a sharp drop in the heat transfer coefficient in the quasi-critical region, and still unable to avoid the risk of a rapid increase in wall temperature.

[0006] In summary, regarding the problem of deteriorated heat transfer in the quasi-critical region of methane under supercritical pressure in the regenerative cooling channel of a liquid oxygen-methane engine, no temperature regulation method has yet emerged that can fundamentally avoid the quasi-critical region and achieve active optimization of cooling performance. Summary of the Invention

[0007] The purpose of this invention is to provide a method and engine for improving the quasi-critical region of methane regeneration cooling based on multi-mode synergistic cooling, in order to solve the problem in the prior art where heat transfer of methane in the quasi-critical region deteriorates under supercritical pressure in the regeneration cooling channel of liquid oxygen methane engines, and there is no technical method that can fundamentally avoid the quasi-critical region and achieve active optimization of cooling performance.

[0008] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0009] The method for improving the quasi-critical region of methane regeneration cooling based on multi-mode synergistic cooling specifically includes:

[0010] The environment of the regenerative cooling channel under actual engine operating conditions is simulated. Based on the real-time pressure of the methane coolant fluid at the outlet of the regenerative cooling channel, the pseudo-critical temperature at the real-time pressure is calculated, and the temperature-position distribution relationship of the mainstream methane coolant along the regenerative cooling channel at the real-time pressure is monitored and obtained.

[0011] Based on the actual operating parameters of the engine, set the maximum allowable wall temperature threshold for the outer wall surface of the regenerative cooling channel;

[0012] The outer wall temperature of the regeneration cooling channel is monitored in real time, and the area where the outer wall temperature is higher than the highest wall temperature threshold is marked as a high heat flux zone.

[0013] Based on the temperature-location distribution relationship, determine the positional relationship between the quasi-critical region corresponding to the quasi-critical temperature and the high heat flux region;

[0014] When the quasi-critical region is close to or partially overlaps with the high heat flux region, the risk of heat transfer deterioration in the quasi-critical region increases, and at least one or more of the following modes are executed simultaneously:

[0015] Temperature pre-regulation mode: The methane coolant fluid is cooled at the inlet of the regeneration cooling channel to reduce the inlet temperature of the methane coolant fluid and increase the cooling capacity, thereby changing the position of the pseudo-critical zone to shift the high heat flux zone.

[0016] Flow pre-regulation mode: Increase the inlet flow rate of methane coolant fluid at the inlet of the regeneration cooling channel to enhance the pressure, cooling capacity and flow rate of the methane coolant fluid in the regeneration cooling channel. By utilizing the enhanced convective heat transfer coefficient and fluid momentum, the low-density thermal boundary layer near the wall of the regeneration cooling channel is disrupted, thereby changing the position of the quasi-critical region to shift the high heat flux region.

[0017] Pressure-driven regulation mode: Increase the inlet pressure of the regeneration cooling channel to raise the quasi-critical temperature, thereby changing the quasi-critical region corresponding to the high heat flux region into a non-quasi-critical region.

[0018] As a preferred embodiment of the present invention, the flow pre-regulation mode further includes:

[0019] Instantly increase the inlet flow rate of the methane coolant fluid, and gradually increase the inlet flow rate of the methane coolant fluid to a preset flow rate threshold.

[0020] As a preferred embodiment of the present invention, the wall temperature of the regeneration cooling channel is monitored in real time during the process of gradually increasing the inlet flow rate of the methane coolant fluid.

[0021] As the wall temperature begins to drop, maintain the current inlet flow rate;

[0022] Otherwise, continue to increase inbound traffic;

[0023] When the inlet flow rate increases to the preset flow rate threshold, if the wall temperature remains above the safety threshold or continues to rise, the flow rate of the methane coolant fluid is increased through the bypass of the regeneration cooling channel.

[0024] As a preferred embodiment of the present invention, when the real-time temperature of the methane coolant fluid at the outlet of the regeneration cooling channel is completely lower than the pseudo-critical danger range;

[0025] If the inlet flow rate is restored to its initial value, or if the real-time temperature at the outlet does not enter the quasi-critical danger range after a preset time, the inlet flow rate is restored to its initial value.

[0026] As a preferred embodiment of the present invention, the temperature pre-regulation mode further includes:

[0027] Instantly reduce the inlet cooling capacity of the methane coolant fluid and gradually decrease the inlet temperature of the methane coolant fluid to a preset temperature threshold.

[0028] As a preferred embodiment of the present invention, the wall temperature of the regeneration cooling channel is monitored in real time during the process of gradient reduction of the inlet temperature of the methane coolant fluid.

[0029] When the wall temperature begins to drop, maintain the current inlet temperature;

[0030] Otherwise, continue to lower the inlet temperature;

[0031] When the inlet temperature increases to the preset temperature threshold, the wall temperature remains above the safety threshold or continues to rise, exceeding the preset temperature threshold and continuing to reduce the inlet temperature.

[0032] As a preferred embodiment of the present invention, the pressure dynamic adjustment mode further includes:

[0033] Instantly boost the inlet pressure of the methane coolant fluid and gradually increase the inlet pressure of the methane coolant fluid to a preset pressure threshold.

[0034] As a preferred embodiment of the present invention, the wall temperature of the regeneration cooling channel is monitored in real time during the process of gradually increasing the inlet pressure of the methane coolant fluid.

[0035] As the wall temperature begins to drop, maintain the current inlet pressure;

[0036] Otherwise, continue to increase the pressure on imports;

[0037] When the inlet pressure increases to the preset pressure threshold, the wall temperature remains above the safety threshold or continues to rise, maintaining the current inlet pressure.

[0038] This invention provides an engine utilizing a quasi-critical region improvement method, the engine comprising at least:

[0039] The regenerative cooling channel is used for heat exchange between methane coolant fluid and the high-temperature combustion gas of the engine. The regenerative cooling channel has a fluid inlet and a fluid outlet.

[0040] A pressure detector is installed at the fluid outlet to detect the real-time pressure at the fluid outlet;

[0041] A temperature detector is installed at the fluid outlet to detect the real-time temperature of the fluid outlet;

[0042] A fuel supply system having a supply outlet connected to the fluid inlet, the fuel supply system having a flow regulating pump to regulate the output flow rate of the methane coolant fluid;

[0043] A cooling system is installed at the fluid inlet of the regeneration cooling channel to cool and reduce the temperature of the methane coolant fluid;

[0044] A pressure regulating system is installed at the fluid inlet of the regeneration cooling channel to increase the inlet fluid pressure of the regeneration cooling channel;

[0045] The control system is electrically connected to the pressure detector, cooling system, pressure regulation system, and fuel supply system.

[0046] The control system monitors and acquires the temperature-position distribution relationship of the mainstream methane coolant along the regeneration cooling channel under the real-time pressure, identifies high heat flux regions, and determines when the quasi-critical region is close to or partially overlaps with the high heat flux region:

[0047] The fuel supply system is controlled to gradually increase the inlet flow rate to a preset flow threshold.

[0048] The cooling system is controlled to gradually reduce the fluid inlet temperature to a preset temperature threshold.

[0049] The pressure regulation system increases the inlet fluid pressure of the regeneration cooling channel to a preset pressure threshold.

[0050] The preset flow rate threshold, preset temperature threshold, and pressure threshold are all set to ensure that the outlet temperature of the regeneration cooling channel is lower than the pseudo-critical danger range, or to cause the wall temperature of the regeneration cooling channel to begin to decrease.

[0051] As a preferred embodiment of the present invention, it further includes a wall temperature detector disposed on the wall surface of the regeneration cooling channel, the wall temperature detector being connected to the control system, and the wall temperature detector being used to detect the wall surface temperature of the regeneration cooling channel in real time;

[0052] The control system is used to control the fuel supply system to maintain the current inlet flow rate and / or control the cooling system to maintain the current inlet temperature when the wall temperature begins to drop.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] This invention, by actively controlling parameters such as methane inlet temperature, flow rate, and pressure, allows the methane coolant to precisely avoid the quasi-critical heat transfer deterioration zone with the lowest heat transfer coefficient, thus maintaining a high heat transfer efficiency. This fundamentally solves the problem of cooling performance degradation caused by abrupt changes in physical properties in the quasi-critical zone, effectively alleviates the problem of uneven heat flux density during thrust chamber regeneration cooling, and avoids combustion gas erosion caused by a surge in wall temperature.

[0055] This invention achieves near-critical region avoidance by adjusting the operating parameters of methane coolant, without increasing the wall thickness of the regenerative cooling thermal structure, effectively controlling the structural dead weight of the engine, and reducing the cost of structural processing and material input, which meets the design requirements of lightweight and low cost of aerospace equipment.

[0056] This invention achieves proactive prevention of heat transfer degradation based on dynamic threshold setting and dual-index early warning logic. Multi-mode coordinated adjustment can accurately match control measures according to different early warning situations, ensuring the stable and reliable operation of the cooling system across the entire engine operating range.

[0057] This invention achieves efficient utilization of cooling capacity without relying on multi-mode coordinated control, and does not need to simply rely on increasing flow rate to compensate for cooling capacity. It ensures precise matching of engine fuel supply and demand, and optimizes the cooling effect without affecting the normal operating performance of the engine. Attached Figure Description

[0058] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0059] Figure 1 This is a schematic diagram of the methane regeneration cooling temperature regulation method based on quasi-critical region avoidance in an embodiment of the present invention. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Example 1:

[0062] A method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy specifically includes:

[0063] The environment of the regenerative cooling channel under actual engine operating conditions is simulated. Based on the real-time pressure of the methane coolant fluid at the outlet of the regenerative cooling channel, the pseudo-critical temperature at the real-time pressure is calculated, and the temperature-position distribution relationship of the mainstream methane coolant along the regenerative cooling channel at the real-time pressure is monitored and obtained.

[0064] Based on the actual operating parameters of the engine, set the maximum allowable wall temperature threshold for the outer wall surface of the regenerative cooling channel;

[0065] The outer wall temperature of the regeneration cooling channel is monitored in real time, and the area where the outer wall temperature is higher than the highest wall temperature threshold is marked as a high heat flux zone.

[0066] Based on the temperature-location distribution relationship, determine the positional relationship between the quasi-critical region corresponding to the quasi-critical temperature and the high heat flux region;

[0067] When the quasi-critical region is close to or partially overlaps with the high heat flux region, the heat transfer deterioration of the quasi-critical region is determined to be an upward airflow, and at least one of the following modes or simultaneous execution is performed:

[0068] Temperature pre-regulation mode: The methane coolant fluid is cooled at the inlet of the regeneration cooling channel to reduce the inlet temperature of the methane coolant fluid and increase the cooling capacity, thereby changing the position of the pseudo-critical zone to shift the high heat flux zone.

[0069] Flow pre-regulation mode: Increase the inlet flow rate of methane coolant fluid at the inlet of the regeneration cooling channel to enhance the pressure and cooling capacity of the regeneration cooling channel. Utilize the enhanced convective heat transfer coefficient and fluid momentum to disrupt the low-density thermal boundary layer near the wall of the regeneration cooling channel, thereby changing the position of the quasi-critical region to shift the high heat flux region.

[0070] Pressure-driven regulation mode: Increase the inlet pressure of the regeneration cooling channel to raise the quasi-critical temperature, thereby changing the quasi-critical region corresponding to the high heat flux region into a non-quasi-critical region.

[0071] The main reason for the deterioration of heat transfer is that heat, heat load, or heat flux density is applied to the wall of the regeneration cooling channel and transferred to the methane coolant fluid through solid wall heat transfer. Therefore, the coolant at the solid-liquid interface is the first to come into contact with heat and rise in temperature, changing from a high-density compressed fluid state to a low-density (gas-like) supercritical state. This state has weak heat transfer capacity, so a thermal boundary layer with large temperature changes is formed, affecting the transfer of heat from the wall to the center of the coolant.

[0072] The relationship between pseudocritical temperature and real-time pressure was obtained using NASA software REFPROP, and it showed a positive correlation.

[0073] In actual operating conditions, the mainstream methane coolant continuously absorbs heat from the inlet to the outlet, and its temperature gradually increases. Therefore, numerical simulation can be used to obtain the temperature-position distribution relationship of the mainstream methane coolant along the regeneration cooling channel under the corresponding pressure.

[0074] Therefore, based on the pseudo-critical temperature under this pressure, the pseudo-critical zone in the regeneration cooling channel is determined according to the temperature-location distribution relationship.

[0075] In practice, the wall temperature of the regenerative cooling channel should be within a certain safe range; otherwise, it will have an adverse effect on the operation of the engine. Based on experiments under actual simulated working conditions, the maximum allowable wall temperature threshold was obtained through analysis.

[0076] The outer wall temperature of the regenerative cooling channel varies depending on the actual operating conditions. Areas with higher temperatures (high heat flux zones) require greater cooling capacity to dissipate heat. When the quasi-critical zone is close to this high heat flux zone, the risk of heat transfer deterioration increases.

[0077] Therefore, by comparing whether the quasi-critical zone where the quasi-critical temperature is located is close to or partially overlaps with the location of the outer wall with a relatively high temperature, we can determine the situation where the risk will increase and then take action.

[0078] The measures taken can be any of the above. When all three are implemented at the same time, they can be implemented in a specific order or simultaneously.

[0079] In the active pressure regulation mode, the pressure can only be adjusted slightly to exceed the engine's requirements for actual operating conditions.

[0080] The flow pre-regulation mode also includes:

[0081] Instantly increase the inlet flow rate of the methane coolant fluid, and gradually increase the inlet flow rate of the methane coolant fluid to a preset flow rate threshold.

[0082] During the process of gradually increasing the inlet flow rate of methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time.

[0083] As the wall temperature begins to drop, maintain the current inlet flow rate;

[0084] Otherwise, continue to increase inbound traffic;

[0085] When the inlet flow rate increases to the preset flow rate threshold, if the wall temperature remains above the safety threshold or continues to rise, the flow rate of the methane coolant fluid is increased through the bypass of the regeneration cooling channel.

[0086] Since the inlet flow rate is limited in actual operating conditions, it is advisable to add a bypass to the path of the regeneration cooling channel to directly increase the flow rate of methane coolant fluid to the location near the quasi-critical region (i.e. increase the cooling capacity, and at the same time, to break the original thermal boundary layer through turbulent flow and enhance the convective heat transfer coefficient), thereby better solving the problem of heat transfer deterioration.

[0087] Because the supply of fuel (methane coolant fluid) has specific requirements in actual application conditions, when the real-time temperature of the methane coolant fluid at the outlet of the regeneration cooling channel is completely below the pseudo-critical danger range;

[0088] If the inlet flow rate is restored to its initial value, or if the real-time temperature at the outlet does not enter the quasi-critical danger range after a preset time, the inlet flow rate is restored to its initial value.

[0089] When the real-time temperature of the methane coolant fluid at the outlet of the regeneration cooling channel is completely below the pseudo-critical danger range;

[0090] If the inlet flow rate is restored to its initial value, or if the real-time temperature at the outlet does not enter the quasi-critical danger range after a preset time, the inlet flow rate is restored to its initial value.

[0091] The temperature pre-adjustment mode also includes:

[0092] Instantly reduce the inlet cooling capacity of the methane coolant fluid and gradually decrease the inlet temperature of the methane coolant fluid to a preset temperature threshold.

[0093] During the process of gradually reducing the inlet temperature of the methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time.

[0094] When the wall temperature begins to drop, maintain the current inlet temperature;

[0095] Otherwise, continue to lower the inlet temperature;

[0096] When the inlet temperature increases to the preset temperature threshold, the wall temperature remains above the safety threshold or continues to rise, exceeding the preset temperature threshold and continuing to reduce the inlet temperature.

[0097] Specifically, the inlet temperature of the methane coolant is reduced by using a refrigeration unit or liquid nitrogen cooling system. By utilizing a lower inlet temperature and increasing cooling capacity, the quasi-critical region is shifted downstream to a safer location, allowing the high heat flux region to bypass the section with the worst methane working fluid properties.

[0098] The pressure dynamic regulation mode also includes:

[0099] The inlet pressure of the methane coolant fluid is instantaneously increased and gradually increased to a preset pressure threshold. Increasing the inlet flow rate is equivalent to increasing the pressure in the regeneration cooling channel, which to some extent raises the quasi-critical temperature, making it more difficult for the methane coolant fluid to reach the quasi-critical temperature. However, since the pressure cannot be increased indefinitely, and increasing the pressure will affect heat exchange.

[0100] During the process of gradually increasing the inlet pressure of the methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time.

[0101] As the wall temperature begins to drop, maintain the current inlet pressure;

[0102] Otherwise, continue to increase the pressure on imports;

[0103] When the inlet pressure increases to the preset pressure threshold, the wall temperature remains above the safety threshold or continues to rise, maintaining the current inlet pressure.

[0104] This method can precisely control the initial temperature and wall temperature of methane entering the cooling channel by means of cooling or heating devices, based on changes in operating parameters such as combustion temperature and heat flux density in the combustion chamber. Through this dynamic adjustment, the methane working fluid is always kept away from the quasi-critical trough region where the heat transfer coefficient is lowest, thereby effectively maintaining and optimizing its cooling capacity.

[0105] The temperature pre-regulation mode, flow pre-regulation mode, and pressure active regulation mode of this embodiment are all different from simple threshold alarms. This stage introduces trend prediction to achieve a leap from post-processing to pre-prevention. Based on the current operating conditions of the engine, the maximum allowable wall temperature rise is obtained in real time.

[0106] Example 2:

[0107] The present invention further provides an engine utilizing a quasi-critical region improvement method, the engine comprising at least:

[0108] The regenerative cooling channel is used for heat exchange between methane coolant fluid and the high-temperature combustion gas of the engine. The regenerative cooling channel has a fluid inlet and a fluid outlet.

[0109] A pressure detector is installed at the fluid outlet to detect the real-time pressure at the fluid outlet.

[0110] A temperature detector is installed at the fluid outlet to detect the real-time temperature of the fluid outlet.

[0111] The fuel supply system has its supply outlet connected to the fluid inlet and includes a flow regulating pump to regulate the output flow rate of the methane coolant fluid.

[0112] The cooling system, located at the fluid inlet of the regeneration cooling channel, cools and de-temperatures the methane coolant fluid.

[0113] A pressure regulation system is installed at the fluid inlet of the regeneration cooling channel to increase the inlet fluid pressure of the regeneration cooling channel;

[0114] The control system includes electrical signal connections to pressure detectors, cooling systems, pressure regulation systems, and fuel supply systems.

[0115] Based on real-time pressure, the control system monitors and acquires the temperature-position distribution relationship of the mainstream methane coolant along the regeneration cooling channel under real-time pressure, identifies high heat flux regions, and detects when the quasi-critical region is close to or partially overlaps with the high heat flux region:

[0116] The fuel supply system is controlled to gradually increase the inlet flow rate to a preset flow threshold.

[0117] The cooling system is controlled to gradually reduce the fluid inlet temperature to a preset temperature threshold.

[0118] The pressure regulation system increases the inlet fluid pressure of the regeneration cooling channel to a preset pressure threshold.

[0119] Among them, the preset flow rate threshold, preset temperature threshold, and pressure threshold are all set to ensure that the outlet temperature of the regeneration cooling channel is lower than the pseudo-critical danger range, or to cause the wall temperature of the regeneration cooling channel to begin to decrease.

[0120] It also includes a wall temperature detector, which is installed on the wall of the regeneration cooling channel. The wall temperature detector is connected to the control system and is used to detect the wall temperature of the regeneration cooling channel in real time.

[0121] The control system is used to control the fuel supply system to maintain the current inlet flow and / or control the cooling system to maintain the current inlet temperature when the wall temperature begins to drop.

[0122] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A method for improving the quasi-critical region of methane regeneration cooling based on multi-mode synergistic cooling, characterized in that, Specifically, it includes: The environment of the regenerative cooling channel under actual engine operating conditions is simulated. Based on the real-time pressure of the methane coolant fluid at the outlet of the regenerative cooling channel, the pseudo-critical temperature at the real-time pressure is calculated, and the temperature-position distribution relationship of the mainstream methane coolant along the regenerative cooling channel at the real-time pressure is monitored and obtained. Based on the actual operating parameters of the engine, set the maximum allowable wall temperature threshold for the outer wall surface of the regenerative cooling channel; The outer wall temperature of the regeneration cooling channel is monitored in real time, and the area where the outer wall temperature is higher than the highest wall temperature threshold is marked as a high heat flux zone. Based on the temperature-location distribution relationship, determine the positional relationship between the quasi-critical region corresponding to the quasi-critical temperature and the high heat flux region; When the quasi-critical region is close to or partially overlaps with the high heat flux region, the risk of heat transfer deterioration in the quasi-critical region increases, and at least one or more of the following modes are executed simultaneously: Temperature pre-regulation mode: The methane coolant fluid is cooled at the inlet of the regeneration cooling channel to reduce the inlet temperature of the methane coolant fluid and increase the cooling capacity, thereby changing the position of the pseudo-critical zone to shift the high heat flux zone. Flow pre-regulation mode: Increase the inlet flow rate of methane coolant fluid at the inlet of the regeneration cooling channel to enhance the pressure, cooling capacity and flow rate of the methane coolant fluid in the regeneration cooling channel. By utilizing the enhanced convective heat transfer coefficient and fluid momentum, the low-density thermal boundary layer near the wall of the regeneration cooling channel is disrupted, thereby changing the position of the quasi-critical region to shift the high heat flux region. Pressure-driven regulation mode: Increase the inlet pressure of the regeneration cooling channel to raise the quasi-critical temperature, thereby changing the quasi-critical region corresponding to the high heat flux region into a non-quasi-critical region.

2. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 1, characterized in that, The flow pre-regulation mode also includes: Instantly increase the inlet flow rate of the methane coolant fluid, and gradually increase the inlet flow rate of the methane coolant fluid to a preset flow rate threshold.

3. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 2, characterized in that, During the process of gradually increasing the inlet flow rate of methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time. As the wall temperature begins to drop, maintain the current inlet flow rate; Otherwise, continue to increase inbound traffic; When the inlet flow rate increases to the preset flow rate threshold, if the wall temperature remains above the safety threshold or continues to rise, the flow rate of the methane coolant fluid is increased through the bypass of the regeneration cooling channel.

4. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 1, characterized in that, When the real-time temperature of the methane coolant fluid at the outlet of the regeneration cooling channel is completely below the pseudo-critical danger range; If the inlet flow rate is restored to its initial value, or if the real-time temperature at the outlet does not enter the quasi-critical danger range after maintaining the initial value for a preset time, the inlet flow rate will be restored to its initial value.

5. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 1, characterized in that, The temperature pre-regulation mode also includes: Instantly reduce the inlet cooling capacity of the methane coolant fluid and gradually decrease the inlet temperature of the methane coolant fluid to a preset temperature threshold.

6. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 5, characterized in that, During the process of gradually reducing the inlet temperature of the methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time. When the wall temperature begins to drop, maintain the current inlet temperature; Otherwise, continue to lower the inlet temperature; When the inlet temperature increases to the preset temperature threshold, the wall temperature remains above the safety threshold or continues to rise, exceeding the preset temperature threshold and continuing to reduce the inlet temperature.

7. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 1, characterized in that, The pressure-dynamic regulation mode also includes: Instantly boost the inlet pressure of the methane coolant fluid and gradually increase the inlet pressure of the methane coolant fluid to a preset pressure threshold.

8. The method for improving the quasi-critical region in the methane regeneration cooling process based on multi-mode synergy according to claim 7, characterized in that, During the process of gradually increasing the inlet pressure of the methane coolant fluid, the wall temperature of the regeneration cooling channel is monitored in real time. As the wall temperature begins to drop, maintain the current inlet pressure; Otherwise, continue to increase the pressure on imports; When the inlet pressure increases to the preset pressure threshold, the wall temperature remains above the safety threshold or continues to rise, maintaining the current inlet pressure.

9. An engine utilizing the quasi-critical region improvement method according to any one of claims 1-8, characterized in that, The engine includes at least: The regenerative cooling channel is used for heat exchange between methane coolant fluid and the high-temperature combustion gas of the engine. The regenerative cooling channel has a fluid inlet and a fluid outlet. A pressure detector is installed at the fluid outlet to detect the real-time pressure at the fluid outlet; A temperature detector is installed at the fluid outlet to detect the real-time temperature of the fluid outlet; A fuel supply system having a supply outlet connected to the fluid inlet, the fuel supply system having a flow regulating pump to regulate the output flow rate of the methane coolant fluid; A cooling system is installed at the fluid inlet of the regeneration cooling channel to cool and reduce the temperature of the methane coolant fluid; A pressure regulating system is installed at the fluid inlet of the regeneration cooling channel to increase the inlet fluid pressure of the regeneration cooling channel; The control system is electrically connected to the pressure detector, cooling system, pressure regulation system, and fuel supply system. The control system monitors and acquires the temperature-position distribution relationship of the mainstream methane coolant along the regeneration cooling channel under the real-time pressure, identifies high heat flux regions, and determines when the quasi-critical region is close to or partially overlaps with the high heat flux region: The fuel supply system is controlled to gradually increase the inlet flow rate to a preset flow threshold. The cooling system is controlled to gradually reduce the fluid inlet temperature to a preset temperature threshold. The pressure regulation system increases the inlet fluid pressure of the regeneration cooling channel to a preset pressure threshold. The preset flow rate threshold, preset temperature threshold, and pressure threshold are all set to ensure that the outlet temperature of the regeneration cooling channel is lower than the pseudo-critical danger range, or to cause the wall temperature of the regeneration cooling channel to begin to decrease.

10. The engine according to claim 9, characterized in that, It also includes a wall temperature detector, which is installed on the wall of the regeneration cooling channel. The wall temperature detector is connected to the control system and is used to detect the wall temperature of the regeneration cooling channel in real time. The control system is used to control the fuel supply system to maintain the current inlet flow rate and / or control the cooling system to maintain the current inlet temperature when the wall temperature begins to drop.

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