Fuel temperature control system, fuel preparation system and fuel preparation method

Abstract

The present invention relates to a fuel temperature control system, comprising: a pre-cooling module, including a first refrigerant pipeline, a pre-cooling heat exchanger, and a first fuel pipeline. The refrigerant flowing in the first refrigerant pipeline flows through the pre-cooling heat exchanger as the cold side, while the fuel flowing in the first fuel pipeline flows through the pre-cooling heat exchanger as the hot side, thereby generating heat exchange to cool the fuel to a pre-cooling temperature above the freezing point of water; and a final cooling module, including a second refrigerant pipeline, a final cooling heat exchanger, and a second fuel pipeline. The refrigerant flowing in the second refrigerant pipeline flows through the final cooling heat exchanger as the cold side, while the fuel flowing in the second fuel pipeline flows through the final cooling heat exchanger as the hot side, thereby generating heat exchange to cool the fuel to a target temperature below the pre-cooling temperature. In this way, the fuel can be cooled to the target temperature in stages, achieving precise control of the water content in the fuel. The present invention also relates to a fuel preparation system and a fuel preparation method.

Description

Technical Field

[0001] The present invention relates to the field of fuel system testing, and more particularly to a fuel temperature control system, a fuel preparation system including the fuel temperature control system, and a fuel preparation method. Background Art

[0002] In recent years, numerous flight accidents caused by fuel system icing have drawn the attention of various airworthiness certification authorities. New airworthiness regulations have been introduced for fuel system certification, requiring civil aircraft to undergo fuel system icing testing to verify and demonstrate compliance with these regulations. For example, icing testing can be conducted in accordance with aircraft fuel system and component icing test standards such as SAE ARP 1401B, GJB 3577-99, and MH / T9004-2013. Currently, only the B787 and A350 have conducted such testing abroad, and domestic experience is lacking.

[0003] Cooling fuel saturated with water is a particularly challenging aspect of fuel system icing testing. This difficulty stems from the low test temperature, where undissolved water in the fuel easily aggregates and forms ice. During the test fuel preparation process, the state of the water in the fuel, the fuel cooling rate, and the accuracy of fuel temperature control must all be considered. Therefore, the design of the fuel cooling system significantly impacts the efficiency, reliability, and energy consumption of the entire fuel system icing test.

[0004] China has achieved some success in low-temperature fuel testing. Refrigeration system designs can be broadly categorized into two types: compressor refrigeration and liquid nitrogen refrigeration. However, due to the large volume of test fuel required for fuel system icing testing and the relatively low extreme test temperatures, compressor refrigeration suffers from poor low-temperature cooling performance, high power consumption, and high noise levels.

[0005] Compared with compressor refrigeration, the cooling capacity of liquid nitrogen as a cold source is significantly improved. Currently, there are two main types of refrigeration methods using liquid nitrogen as a cold source. The first is direct refrigeration with liquid nitrogen, for example, see CN205678969U. However, this existing liquid nitrogen refrigeration system mostly uses liquid nitrogen to directly exchange heat with the fuel through a heat exchanger. Its temperature control ability is poor, which can easily cause the moisture in the fuel to accumulate in the heat exchanger, resulting in a decrease in the water content of the test fuel, or even test failure. The second is intermediate medium circulation refrigeration, which can effectively improve the fuel refrigeration efficiency and temperature control accuracy. For example, CN 205203423U describes that the first-stage heat exchanger cannot cool the test fuel to the target temperature, and the second-stage compressed gas must be used to cool it down again. This existing solution has high requirements on the compressor refrigeration power, and adopts a circulation refrigeration method. The cooling process has a great impact on the water content in the fuel.

[0006] In general, both methods utilize fuel circulation refrigeration, cooling the prepared fuel through refrigeration equipment to the target temperature. However, as the low-temperature fuel circulates multiple times through the equipment, a large amount of water accumulates in the circulation lines, significantly reducing the fuel's water content. This water content is difficult to precisely control.

[0007] Therefore, there is always a demand for a fuel preparation system that can have better temperature control performance and maintain the water content in the fuel, so as to improve the efficiency of the fuel system icing test and reduce the test cost. Summary of the Invention

[0008] The present invention relates to a fuel temperature control system, which may include: a pre-cooling module, which may include a first refrigerant pipeline, a pre-cooling heat exchanger and a first fuel pipeline, wherein the refrigerant flowing in the first refrigerant pipeline flows through the pre-cooling heat exchanger as a cold side, and the fuel flowing in the first fuel pipeline flows through the pre-cooling heat exchanger as a hot side, so as to cool the fuel to a pre-cooling temperature by generating heat exchange, and the pre-cooling temperature is higher than the freezing point of water; a final cooling module, which may include a second refrigerant pipeline, a final cooling heat exchanger and a second fuel pipeline, wherein the refrigerant flowing in the second refrigerant pipeline flows through the final cooling heat exchanger as a cold side, and the fuel flowing in the second fuel pipeline flows through the final cooling heat exchanger as a hot side, so as to cool the fuel to a target temperature lower than the pre-cooling temperature by generating heat exchange.

[0009] The fuel temperature control system of the present invention can cool the fuel to the target temperature in stages, thereby reducing the possibility of water accumulation in the fuel circulation pipeline, achieving precise control of the water content in the fuel, and thus improving the efficiency of the fuel system icing test.

[0010] In some embodiments, the final cooling heat exchanger may include a final cooling first-stage heat exchanger and a final cooling second-stage heat exchanger, and the final cooling module may further include an intermediate medium heat exchange pipeline, and the intermediate medium may circulate between the final cooling first-stage heat exchanger and the final cooling second-stage heat exchanger via the intermediate medium heat exchange pipeline, wherein the refrigerant on the second refrigerant pipeline flows through the final cooling first-stage heat exchanger, so that the refrigerant realizes heat exchange with the intermediate medium through the final cooling first-stage heat exchanger, and wherein the fuel with a pre-cooling temperature flows through the final cooling second-stage heat exchanger, so that the intermediate medium realizes heat exchange with the fuel through the final cooling second-stage heat exchanger.

[0011] Through two-stage final cooling, the requirement for refrigeration power can be reduced, the test requirements can be met, and the preparation efficiency can be improved.

[0012] Preferably, the first fuel line is fluidically connected to a fuel storage tank for containing fuel, so that the fuel can circulate through the first fuel line and the fuel storage tank. The circulating flow can quickly reduce the temperature of the fuel and maintain the fuel at a pre-cooling temperature in the fuel storage tank, thereby preparing for subsequent final cooling.

[0013] Advantageously, the first fuel line can include a first low-temperature fuel line and a first high-temperature fuel line. Fuel from the fuel storage tank can flow to the pre-cooling heat exchanger via the first high-temperature fuel line, and fuel heat-exchanged in the pre-cooling heat exchanger can flow back to the fuel storage tank via the first low-temperature fuel line. This enables a one-way circulation of fuel between the fuel storage tank and the pre-cooling heat exchanger.

[0014] In particular, one end of the second fuel line can be fluidically connected to a fuel storage tank for containing fuel, and the other end of the second fuel line can be fluidically connected to the test tank, so that the fuel from the fuel storage tank flows through the final cooling heat exchanger and directly flows into the test tank at the target temperature.

[0015] In this way, the fuel can be directly cooled to the target temperature according to the required flow rate, avoiding circulating heat exchange at sub-zero temperatures, effectively reducing water loss, achieving precise control of the water content in the fuel, and greatly improving the success rate of fuel preparation.

[0016] In particular, the pre-cooling temperature may be 2-5 degrees Celsius, and / or the final cooling temperature may be -5 degrees Celsius to -40 degrees Celsius.

[0017] By keeping the precooling temperature above the freezing temperature, the accumulation of water and / or ice in the circulation pipeline during the precooling process can be avoided, the water loss can be reduced, and the test accuracy can be improved.

[0018] Preferably, the first fuel line and the second fuel line can be isolated from each other. With these relatively independent fuel lines, the fuel is not circulated between the pre-cooling module and the final cooling module for cooling. Instead, the fuel is pre-cooled in stages and then final-cooled independently as needed. For example, the pre-cooling and final cooling stages can include other stages or a desired duration (during which the fuel can be maintained at its pre-cooling temperature or another suitable lower temperature).

[0019] The present invention also relates to a fuel preparation system, which may include: the fuel temperature control system as described above; a cold source device for providing refrigerant to the fuel temperature control system; a fuel storage tank for containing fuel, the fuel from the fuel storage tank can be cooled to a pre-cooling temperature through a pre-cooling module; and a collecting tank, the fuel cooled by the pre-cooling module can flow from the fuel storage tank through a final cooling module at a target temperature into the collecting tank.

[0020] The fuel preparation system of the present invention can obtain a precisely controllable fuel water content, thereby improving test efficiency and avoiding inaccurate results caused by excessive water addition.

[0021] Advantageously, the fuel preparation system may further include a water adding module, which may be configured to add water to the fuel before the fuel in the fuel storage tank is cooled to the precooling temperature by the precooling module, so as to achieve a good effect of maintaining the fuel temperature during the water adding process.

[0022] In addition, the present invention also relates to a fuel preparation method, which may include: a pre-cooling step: the fuel in a fuel storage tank for containing the fuel can be cooled to a pre-cooling temperature through a pre-cooling module, and the pre-cooling temperature is higher than the freezing temperature of water, wherein, in the pre-cooling module, the refrigerant flows through the pre-cooling heat exchanger as the cold side, and the fuel from the fuel storage tank flows through the pre-cooling heat exchanger as the hot side to produce heat exchange; a final cooling step: the fuel in the fuel storage tank can be cooled to a target temperature lower than the pre-cooling temperature through the final cooling module, wherein, in the final cooling module, the refrigerant can flow through the final cooling heat exchanger as the cold side, and the fuel from the fuel storage tank can flow through the final cooling heat exchanger as the hot side to produce heat exchange.

[0023] The fuel preparation method of the present invention achieves initial fuel temperature adjustment through a pre-cooling step and maintains it at the pre-cooling temperature. This effectively prevents moisture from freezing and accumulating during the cycle, while also reducing the refrigeration power required for the final cooling step. This final cooling step allows the fuel to be directly cooled to the target temperature at the required flow rate, significantly improving the success rate of fuel preparation.

[0024] In particular, the final cooling step can be performed after the pre-cooling step is completed. Thus, the task of cooling the fuel to the target temperature can be completed flexibly when needed, without the need to perform final cooling immediately after reaching the pre-cooling temperature.

[0025] Preferably, water may be added to the fuel before performing the pre-cooling step.

[0026] Particularly preferably, the final cooling step may include causing the fuel to flow into the collection tank at a target temperature, thereby avoiding circulating heat exchange at freezing temperatures and achieving precise control of the water content in the fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The flow path principle diagram of a fuel preparation system according to an embodiment of the present invention is schematically shown.

[0028] List of reference numerals:

[0029] 100 Fuel temperature control system;

[0030] 120 liquid nitrogen pipeline;

[0031] 121 first refrigerant pipeline;

[0032] 122 second refrigerant pipeline;

[0033] 132 solenoid valve;

[0034] 134 temperature sensor;

[0035] 135 pre-cooling fuel circulation pump;

[0036] 137 Final cooling fuel circulation pump;

[0037] 140 discharge line;

[0038] 142 nitrogen exhaust port;

[0039] 150 pre-cooling heat exchanger;

[0040] 162 First fuel low temperature pipeline;

[0041] 164 First fuel high temperature pipeline;

[0042] 172 Final cooling first stage heat exchanger;

[0043] 174 Final cooling secondary heat exchanger;

[0044] 182 Low-temperature intermediate medium heat exchange pipeline;

[0045] 184 High-temperature intermediate medium heat exchange pipeline;

[0046] 186 Intermediate medium circulation pump;

[0047] 187 Intermediate medium flow meter;

[0048] 188 Intermediate medium flow control valve;

[0049] 189 intermediate medium storage tank;

[0050] 192 Second fuel low temperature pipeline;

[0051] 194 Second fuel high temperature pipeline;

[0052] 210 cooling source device;

[0053] 220 fuel tanks;

[0054] 230 Test fuel tank. DETAILED DESCRIPTION

[0055] The present invention will be further described below with reference to specific embodiments and drawings, but the scope of protection of the present invention should not be limited thereto.

[0056] The present invention primarily relates to the field of fuel system testing. While the present invention primarily addresses the problem of reducing the accumulation of water within the refrigeration system during fuel cooling or refrigeration, which can lead to inaccurate test results and low test efficiency, the fuel temperature control system, fuel preparation system, and fuel preparation method of the present invention are not limited to fuel testing applications and can be used in any application requiring fuel water content control.

[0057] Although the present invention is described using aircraft fuel as an example, the system and method of the present invention are not limited to application in the aerospace field. For example, they can also be used in ships, vehicles, operating machinery, and other occasions, as long as these occasions require controlling the water content in the fuel during the cooling process.

[0058] The fuel temperature control system of the present invention can be used as part of a fuel preparation system to control the cooling temperature of the fuel and prevent an undesirable reduction in the water content of the fuel during the fuel preparation process. However, it will be appreciated that the fuel temperature control system of the present invention can also be provided independently of other devices or modules of the fuel preparation system, for example, provided or sold separately.

[0059] In the present invention, the term "module" is intended to cover various devices and components that realize a given function (for example, pre-cooling, final cooling, etc.). The "module" can also be regarded as working as a system. The "module" can include its own independent control device, but can also be controlled by the controller of the entire system.

[0060] In the present invention, the term "pipeline" refers to various tubular flow paths that contain fluids. Its cross-sectional shape is not limited, and its physical parameters, such as flow resistance, diameter, etc. are not limited, as long as it can achieve the specified function (for example, fluid transfer).

[0061] First, the present invention includes a fuel temperature control system 100, which is used to control the temperature of fuel to, mainly to, a target temperature. Here, the fuel to be controlled is not limited to the fuel from a device containing fuel, but can be the fuel flowing in a fuel pipeline.

[0062] The fuel temperature control system 100 according to the present invention can achieve staged fuel temperature control. To this end, the fuel temperature control system 100 can include two different cooling systems or modules. These two cooling systems or modules are relatively independent of each other, meaning they do not operate in series, unlike the two-stage cooling system used in the prior art. However, it is worth noting that "relatively independent" does not exclude the possibility of shared piping or components; it simply means that the functions of each system do not depend on the simultaneous operation of the other.

[0063] Specifically, the fuel temperature control system 100 includes a precooling module for reducing the fuel temperature to a precooling temperature. This precooling temperature is typically lower than, and particularly significantly lower than, the temperature of the fuel before cooling. The present invention does not preclude performing other temperature control on the fuel before the precooling module is used to cool the fuel to the precooling temperature, such as maintaining the fuel at a desired temperature that is higher than, and particularly significantly higher than, the precooling temperature.

[0064] The pre-cooling module may include a first refrigerant line 121, through which a refrigerant, particularly a refrigerant from a cold source device 210, may flow. In the present invention, the refrigerant is, for example, liquid nitrogen, but other known refrigerants are also contemplated. The cold source device 210 may be part of the pre-cooling module, but may be provided independently of the pre-cooling module.

[0065] The pre-cooling module may also include a first fuel line, through which fuel, particularly fuel to be subjected to system icing testing, can flow. This fuel may come from a fuel storage tank 220, which is used to store fuel. Fuel storage tank 220 may be part of the pre-cooling module, but may also be located independently of the pre-cooling module. In the present invention, the term "tank" may refer to any suitable container for holding fuel, and does not limit the container's shape, size, or sealing properties. However, it should be understood that the fuel to be pre-cooled in the first fuel line may not come from fuel storage tank 220, but rather from another fuel line.

[0066] In order to achieve cooling, the pre-cooling module may include a pre-cooling heat exchanger 150, in particular, only one pre-cooling heat exchanger 150. Generally, a heat exchanger includes a cold side (or cold end) and a hot side (or hot end), and the fluids flowing on the cold side and the hot side may not be in direct contact with each other. In the present invention, the refrigerant flowing on the first refrigerant pipeline 121, such as liquid nitrogen, flows through the pre-cooling heat exchanger 150 as the cold side, while the fuel flowing on the first fuel pipeline flows through the pre-cooling heat exchanger 150 as the hot side, so as to cool the fuel (flowing on the first fuel pipeline) to the pre-cooling temperature by generating heat exchange, that is, to achieve pre-cooling temperature reduction.

[0067] In the present invention, the precooling temperature should be maintained above the freezing point of water, typically above 0°C (although it can vary depending on the pressure). By maintaining the precooling temperature above freezing, even as the fuel circulates and cools within the precooling module, water in the fuel will not accumulate in the pipelines (i.e., free water in the fuel will not freeze), thereby preventing accurate determination of the fuel's water content. Preferably, the precooling temperature is 2-5°C, slightly above the freezing point of water.

[0068] As previously mentioned, before cooling the fuel to the pre-cooling temperature, the fuel temperature can also be controlled to, and in particular maintained at, a temperature higher than the pre-cooling temperature using a heat exchanger, such as the pre-cooling heat exchanger 150. This temperature can be, for example, 25-35 degrees Celsius, in particular 26-32 degrees Celsius, for example 29 degrees Celsius.

[0069] The fuel temperature control system 100 of the present invention also includes a final cooling module for cooling the fuel to a target temperature below the pre-cooling temperature. The target temperature is typically below zero, preferably between -5°C and -40°C, such as -5°C, -10°C, -11°C, -12°C, -13°C, -14°C, -20°C, -25°C, -30°C, or -40°C. It should be noted that while the present invention only describes a pre-cooling module and a final cooling module, the fuel temperature control system 100 may also include other cooling modules for cooling the fuel to any suitable temperature between the pre-cooling temperature and the target temperature.

[0070] The final cooling module may include a second refrigerant line 122, through which a refrigerant, particularly a refrigerant from a cold source device 210, may flow. As previously mentioned, the refrigerant may be, for example, liquid nitrogen, but other known refrigerants are also contemplated. The cold source device 210 may be part of the final cooling module, but may also be provided independently of the final cooling module.

[0071] The cold source device 210 for supplying refrigerant to the pre-cooling module and the cold source device 210 for supplying refrigerant to the final cooling module can be the same, and preferably are the same, but this is not required. The first refrigerant pipeline 121 and the second refrigerant pipeline 122 preferably share at least a portion of the pipe section, especially the pipeline immediately after leaving the cold source device 210 and the pipeline flowing to the refrigerant recovery device. When the refrigerant is liquid nitrogen, the refrigerant recovery device can be, for example, the nitrogen discharge port 142.

[0072] In the present invention, the shared portion of piping between the first refrigerant pipeline 121 and the second refrigerant pipeline 122 does not affect the relative independence of the pre-cooling module and the final cooling module. For example, the refrigerant pipeline originating from the cold source device 210 may be bifurcated into multiple routes, one of which leads to the pre-cooling heat exchanger 150 and another to the final cooling heat exchanger (described below). For another example, the first refrigerant pipeline 121, which passes through the pre-cooling heat exchanger 150 and is downstream of the pre-cooling heat exchanger 150 in the direction of refrigerant flow, and the second refrigerant pipeline 122, which passes through the final cooling heat exchanger and is downstream of the final cooling heat exchanger in the direction of refrigerant flow, may be joined via a shared pipeline to a refrigerant collection device, as this would substantially not affect the respective operations of the pre-cooling module and the final cooling module. Although not described in detail, those skilled in the art will appreciate that a switching valve or multi-way valve may be provided to switch or maintain flow paths.

[0073] The final cooling module may include a second fuel line through which fuel, particularly fuel to be subjected to system icing testing, can flow. This fuel may originate from a fuel storage tank 220, which is used to store fuel. Preferably, the temperature of the fuel flowing from the fuel storage tank 220 into the second fuel line has already reached a pre-cooling temperature, for example, 2-5 degrees Celsius. However, it will be appreciated that the temperature of the fuel flowing into the second fuel line may fluctuate above or below the pre-cooling temperature (e.g., due to significant fluctuations in the environment outside the fuel storage tank 220), without affecting the functionality of the present invention.

[0074] The final cooling module can be a final cooling heat exchanger. As previously mentioned, a heat exchanger includes a cold side (or cold end) and a hot side (or hot end), and the fluids flowing on the cold and hot sides may not directly contact each other. In the present invention, the refrigerant flowing in the second refrigerant line 122, such as liquid nitrogen, flows through the final cooling heat exchanger as the cold side, while the fuel flowing in the second fuel line (e.g., fuel that has reached a pre-cooling temperature) flows through the final cooling heat exchanger as the hot side. This generates heat exchange to cool the fuel (flowing in the second fuel line) to the target temperature.

[0075] If no further cooling module is provided between the pre-cooling module and the final cooling module, the pre-cooling temperature may be far from the target temperature, for example, more than 15 degrees Celsius. The final cooling heat exchanger may be designed as a multi-stage, especially a two-stage, heat exchange device, but this is not necessary.

[0076] Specifically, the final cooling heat exchanger may include a primary final cooling heat exchanger 172 and a secondary final cooling heat exchanger 174. To this end, the final cooling module may further include an intermediate medium heat exchange pipeline, through which the intermediate medium circulates between the primary final cooling heat exchanger 172 and the secondary final cooling heat exchanger 174. In this case, the refrigerant in the second refrigerant pipeline 122 flows through the primary final cooling heat exchanger 172 as the cold side, exchanging heat with the intermediate medium through the primary final cooling heat exchanger 172. This means that the refrigerant cools the intermediate medium. Meanwhile, the fuel, particularly fuel at the pre-cooling temperature, flows through the secondary final cooling heat exchanger 174 as the hot side, exchanging heat with the fuel through the secondary final cooling heat exchanger 174. This means that the intermediate medium cools the fuel. Therefore, the intermediate medium circulates in the intermediate medium heat exchange pipeline, and the primary final cooling heat exchanger 172 and the secondary final cooling heat exchanger 174 are arranged in series with respect to the intermediate medium heat exchange pipeline.

[0077] Advantageously, at least one of an intermediate medium circulation pump 186 , an intermediate medium flow meter 187 , and an intermediate medium flow regulating valve 188 , preferably all three, may be arranged on the intermediate medium heat exchange pipeline.

[0078] Since the present invention relates to staged cooling rather than multi-stage cooling, the first fuel line is preferably isolated from the second fuel line. More preferably, the pre-cooling module and the final cooling module are also relatively isolated (except for some shared lines in some embodiments).

[0079] In the pre-cooling module, the first fuel line is preferably in fluid communication with the aforementioned fuel storage tank 220, allowing the fuel to circulate through the first fuel line and the fuel storage tank 220. During the pre-cooling process, the pre-cooling heat exchanger 150 pre-cools the fuel to a pre-cooling temperature of not less than zero degrees Celsius (preferably slightly above zero degrees Celsius) and maintains this temperature. This effectively prevents moisture from freezing and accumulating in the circulation system piping during the fuel circulation process, thereby rapidly reducing the water content in the fuel.

[0080] In some embodiments, the first fuel line may include a first low-temperature fuel line 162 and a first high-temperature fuel line 164. Fuel from the fuel storage tank 220 flows to the pre-cooling heat exchanger 150 via the first high-temperature fuel line 164, while the fuel heat-exchanged in the pre-cooling heat exchanger 150 flows back to the fuel storage tank 220 via the first low-temperature fuel line 162. In other words, the line upstream of the pre-cooling heat exchanger 150 in the direction of fuel flow is referred to as the first high-temperature fuel line 164, and the line downstream of the pre-cooling heat exchanger 150 in the direction of fuel flow is referred to as the first low-temperature fuel line 162 (because the fuel in this line has already been cooled). Thus, a unidirectional circulation of fuel can be achieved.

[0081] For the final cooling module, one end of the second fuel line is preferably in fluid communication with the fuel storage tank 220, which holds the fuel, while the other end of the second fuel line is in fluid communication with the test tank 230. This allows fuel from the fuel storage tank 220 to flow directly into the test tank 230 after being further cooled (e.g., to a target temperature) by the final cooling heat exchanger. In other words, the fuel cooled to the target temperature does not recirculate back into the fuel storage tank 220, but instead flows directly to the test tank 230 at the target temperature. Since the low-temperature fuel is added to the test tank 230, it does not need to be refrigerated, effectively reducing the possibility of water accumulation in the fuel within the refrigeration cycle. This advantageously enables precise control of the water content in the fuel, significantly reducing the initial water addition amount (preventing excessive water addition due to water reduction) and fuel dispensing time, and improving fuel dispensing success rate. Furthermore, it should be understood that temperatures slightly above or below the target temperature are also within the scope of the present invention.

[0082] Advantageously, at least one of a pre-cooling fuel circulation pump 135 and a pre-cooling fuel flow regulating valve, preferably both, may be arranged on the first fuel line. Furthermore, advantageously, at least one of a final-cooling fuel circulation pump 137 and a final-cooling fuel flow regulating valve, preferably both, may be arranged on the second fuel line.

[0083] The present invention also relates to a fuel preparation system that can prepare fuel for, for example, icing tests. The fuel preparation system can include the aforementioned fuel temperature control system 100. The fuel preparation system can also include a cooling device 210 for providing refrigerant to the fuel temperature control system 100. It is also conceivable that the cooling device 210 is part of the fuel temperature control system 100.

[0084] The fuel preparation system may also include a fuel storage tank 220 for storing fuel. Fuel from this fuel storage tank 220 can be cooled to a pre-cooling temperature by a pre-cooling module. As previously mentioned, the pre-cooled fuel is preferably returned to the fuel storage tank 220 and continuously circulated to ensure that the fuel in the fuel storage tank 220 reaches the pre-cooling temperature. The volume of fuel in the fuel storage tank 220 can be adjusted based on factors such as test requirements and cooling time.

[0085] Furthermore, the fuel preparation system may include a test fuel tank 230. Fuel cooled by the pre-cooling module can flow from the fuel storage tank 220 to the test fuel tank 230 at the target temperature via the final cooling module. However, it should be understood that the fuel preparation system of the present invention may also include other containers for storing fuel cooled to the target temperature, and is not necessarily limited to test fuel tanks. For example, any suitable collection container or collection tank may be included.

[0086] Preferably, the fuel preparation system may include a water addition module for adding water, or injecting water, to the fuel before cooling. During the water addition process, a cooling module, such as a pre-cooling module, may be used to maintain the fuel at a specified temperature, such as 25-30 degrees Celsius. Preferably, the water addition module may be configured to add water to the fuel before the pre-cooling module cools the fuel in fuel storage tank 220 to the pre-cooling temperature, rather than directly adding water to the fuel in the first fuel line at the beginning of the pre-cooling process.

[0087] More specifically, the duration of fuel water addition can be, for example, 1-2 hours. Preferably, the fuel needs to be continuously circulated and stirred during the water addition process. Without intervention, the fuel temperature may continue to rise. The recommended water addition temperature is 29°C ± 3°C. The pre-cooling module can maintain the fuel at the required water addition temperature. This means that the pre-cooling module not only cools the water-containing fuel to the pre-cooling temperature but also maintains the fuel temperature during the water addition process.

[0088] Finally, the present invention also relates to a fuel preparation method comprising at least two steps. The method may include a precooling step: cooling the fuel within a fuel storage tank 220 to a precooling temperature greater than zero degrees Celsius. This precooling step is primarily performed using a precooling module, in which a refrigerant flows through a precooling heat exchanger 150 as the cold side, while fuel, such as fuel from the fuel storage tank 220, flows through the precooling heat exchanger 150 as the hot side, thereby exchanging heat.

[0089] The method may include a final cooling step: cooling the fuel in the fuel storage tank 220 to a target temperature lower than the pre-cooling temperature. This final cooling step is primarily performed using a final cooling module. In this final cooling module, refrigerant flows through a final cooling heat exchanger as the cold side, while fuel from the fuel storage tank 220 flows through the final cooling heat exchanger as the hot side, thereby exchanging heat. As previously mentioned, the final cooling heat exchanger can be configured as a multi-stage, particularly a two-stage, heat exchanger, and will not be further described here.

[0090] Preferably, the final cooling step can be performed after the pre-cooling step is completed. Here, "completed" means that the temperature of the fuel in fuel storage tank 220 has reached the pre-cooling temperature through the circulating flow. In other words, the final cooling step is not performed simultaneously with the pre-cooling step, but rather is performed in separate stages, operating relatively independently of each other, rather than in a series of multiple stages.

[0091] Also preferably, water is added to the fuel before the pre-cooling step is performed. More preferably, the fuel is kept at a specified temperature during the water addition process, which is significantly higher than the pre-cooling temperature, for example 20-28 degrees Celsius higher.

[0092] It will be appreciated that the method of the present invention is not limited to the two cooling steps described above, but may include additional cooling steps therebetween to cool the fuel to a temperature between the pre-cooling temperature and the target temperature. However, preferably, the present invention includes only the pre-cooling and final cooling stages.

[0093] Furthermore, if two-stage cooling is employed in the heat-finishing module or heat-finishing step, the target cooling temperature T3 can be determined as needed, for example, based on test requirements. The intermediate medium cooling temperature T2 and intermediate medium flow rate S2 can then be determined (e.g., calculated) based on the initial temperature T1 (e.g., pre-cooling temperature), the target temperature T2, the desired fuel flow rate, and the physical parameters of the heat exchanger (e.g., heat transfer coefficient, heat transfer area, etc.). This allows single-stage cooling to avoid generating an excessively large cooling temperature differential (i.e., the temperature differential between the cold side and the hot side can be less than, for example, 13 degrees Celsius).

[0094] The fuel preparation system and method of the present invention utilizes two relatively independent cooling modules. The pre-cooling system achieves initial fuel temperature adjustment and maintains it at the pre-cooling temperature, effectively preventing moisture from freezing and accumulating in the circulation piping during circulation, while also reducing the cooling power required by the final cooling system. The final cooling system directly cools the fuel to the target temperature at the required flow rate, avoiding heat exchange below the freezing point, effectively reducing moisture loss, and enabling precise control of fuel moisture content, significantly improving the success rate of fuel configuration.

[0095] Next, with the help of Figure 1 To further explain the layout of the fuel preparation system of the present invention. However, it can be understood that Figure 1 This is merely exemplary and the present invention may be used with Figure 1 Different fixtures and layouts.

[0096] Figure 1 The embodiment of the present invention illustrates a fuel preparation system using liquid nitrogen as a refrigerant, capable of preparing low-temperature, water-containing fuel for low-temperature fuel testing. The fuel preparation system includes a fuel temperature control system 100, a fuel storage tank 220, a water addition module, and a test fuel tank 230. The water addition module is primarily used to add water to the fuel before cooling.

[0097] First, the fuel temperature can be maintained during the fuel water addition process, for example, at 25-30 degrees Celsius. The fuel temperature can be maintained by using the pre-cooling module of the present invention, but other temperature control devices can also be used, which can flexibly adjust the fuel temperature.

[0098] Subsequently, the fuel may be pre-cooled to a pre-cooling temperature that is higher than the freezing temperature, for example, 2-5 degrees C. Preferably, after the pre-cooling temperature is achieved, the fuel may continue to be maintained at this temperature.

[0099] like Figure 1 As shown in FIG, a liquid nitrogen storage tank serves as a cold source device 210 for providing refrigerant. Liquid nitrogen flows to a pre-cooling heat exchanger 150 or a final cooling heat exchanger via a (shared) liquid nitrogen pipeline 120. Here, liquid nitrogen can flow to the pre-cooling heat exchanger 150 via a first refrigerant pipeline 121. Liquid nitrogen can also flow to the final cooling heat exchanger via a second refrigerant pipeline 122. The liquid nitrogen flowing on the first refrigerant pipeline 121 flows to a nitrogen discharge port 142 after passing through the pre-cooling heat exchanger 150. The pipeline downstream of the pre-cooling heat exchanger 150 can also be referred to as a discharge pipeline 140.

[0100] On the hot side of the pre-cooling heat exchanger 150, Figure 1The first fuel line is shown, which can be divided into a first low-temperature fuel line 162 and a first high-temperature fuel line 164. Fuel from the fuel storage tank 220 flows to the pre-cooling heat exchanger 150 via the first high-temperature fuel line 164. The fuel, after heat exchange in the pre-cooling heat exchanger 150, flows back to the fuel storage tank 220 via the first low-temperature fuel line 162. Because the first fuel line is connected between the fuel storage tank 220 and the pre-cooling heat exchanger 150, the fuel can circulate in a loop between them. Therefore, this first fuel line can also be called a fuel circulation line.

[0101] In addition to the above devices and components, Figure 1 Also shown are multiple temperature sensors 134, which can be arranged, for example, on the first low-temperature fuel line 162 and / or the first high-temperature fuel line 164. Furthermore, a pre-cooling fuel circulation pump 135 is provided to circulate the fuel. Furthermore, a cold fuel flow control valve can be provided to regulate the flow rate.

[0102] exist Figure 1 In the embodiment, during the pre-cooling process, solenoid valve 132 can be used to control the injection of liquid nitrogen into pre-cooling heat exchanger 150 to exchange heat with the fuel. This allows the pre-cooled fuel to circulate and mix uniformly. By controlling the amount of liquid nitrogen injected, the required fuel cooling / maintenance can be achieved.

[0103] The fuel can then be cooled to a target temperature below the pre-cooling temperature. Figure 1 In the embodiment of the present invention, the final cooling module or the final cooling step is mainly used to cool the fuel from the pre-cooling temperature to the target (test) temperature according to the required flow rate.

[0104] The final cooling module may include a solenoid valve 132, a final cooling first-stage heat exchanger 172, a low-temperature intermediate medium heat exchange pipeline 182 (or a low-temperature intermediate medium circulation pipeline), a high-temperature intermediate medium heat exchange pipeline 184 (or a high-temperature intermediate medium circulation pipeline), multiple temperature sensors 134, an intermediate medium circulation pump 186, an intermediate medium storage tank 189, an intermediate medium (circulation) flow regulating valve 188, a final cooling second-stage heat exchanger 174, a second fuel high-temperature pipeline 194 (also called a final cooling high-temperature fuel circulation pipeline), a final cooling low-temperature fuel circulation pipeline, a pre-cooling fuel flow regulating valve, and a pre-cooling fuel circulation pump 135.

[0105] During the final cooling process, the solenoid valve 132 controls the amount of liquid nitrogen sprayed into the final cooling (primary) heat exchanger 172 to adjust the intermediate medium temperature. The intermediate medium circulation pump and circulation pipeline then circulate the intermediate medium between the final cooling (primary) heat exchanger 172 and the final cooling (secondary) heat exchanger 174. The intermediate medium circulation process transfers cooling energy to the fuel, adjusting the fuel flow rate based on demand. By matching the intermediate medium temperature with the circulation flow rate, the fuel reaches the target temperature after heat exchange in the final cooling (secondary) heat exchanger and is then directly filled into the test fuel tank 230.

[0106] Thus, the pre-cooling of the present invention adopts circulating refrigeration, and the direct injection of liquid nitrogen has no temperature difference restriction, the cooling capacity is sufficient, and moisture will not accumulate in the pipeline. The final cooling of the present invention adopts direct refrigeration, and the fuel is cooled to the target temperature in one time through the heat exchanger according to the fuel flow requirement. There is no need for circulating refrigeration, and the moisture content is quite stable.

[0107] Although various embodiments of the present invention are described in the drawings with reference to fuel for icing tests in the aircraft field, it should be understood that embodiments within the scope of the present invention may be applied to other applications having similar structures and / or functions, such as ships, vehicles, etc.

[0108] The foregoing description has presented numerous features and advantages, including various alternative embodiments, and details of the structure and function of apparatus and methods. This description is intended to be illustrative and not exhaustive or limiting.

[0109] It will be apparent to those skilled in the art that various modifications may be made within the full scope indicated by the broad general meaning of the terms expressed in the appended claims, especially in terms of structure, materials, elements, components, shapes, sizes and arrangements of components, including combinations of these aspects within the scope of the principles described herein. To the extent that these various modifications do not depart from the spirit and scope of the appended claims, they are intended to be included therein.

Claims

1. A fuel temperature control system, characterized in that: The fuel temperature control system includes: a pre-cooling module comprising a first refrigerant line, a pre-cooling heat exchanger, and a first fuel line, wherein the refrigerant flowing in the first refrigerant line flows through the pre-cooling heat exchanger as a cold side, and the fuel flowing in the first fuel line flows through the pre-cooling heat exchanger as a hot side, thereby cooling the fuel to a pre-cooling temperature by generating heat exchange, wherein the pre-cooling temperature is higher than the freezing point of water; the first fuel line is fluidically connected to a fuel storage tank for containing fuel, so that the fuel can circulate through the first fuel line and the fuel storage tank; A final cooling module, the final cooling module includes a second refrigerant pipeline, a final cooling heat exchanger and a second fuel pipeline, wherein the second fuel pipeline and the first fuel pipeline are isolated from each other, the refrigerant flowing in the second refrigerant pipeline flows through the final cooling heat exchanger as a cold side, and the fuel flowing in the second fuel pipeline and cooled to a pre-cooling temperature by the pre-cooling module flows through the final cooling heat exchanger as a hot side, so as to cool the fuel to a target temperature lower than the pre-cooling temperature by generating heat exchange; one end of the second fuel pipeline is fluidly connected to a fuel storage tank for accommodating fuel, and the other end of the second fuel pipeline is fluidly connected to a test fuel tank, so that the fuel from the fuel storage tank flows through the final cooling heat exchanger and directly flows into the test fuel tank at the target temperature.

2. The fuel temperature control system according to claim 1, wherein: The final cooling heat exchanger includes a final cooling primary heat exchanger and a final cooling secondary heat exchanger. The final cooling module also includes an intermediate medium heat exchange pipeline. The intermediate medium circulates between the final cooling primary heat exchanger and the final cooling secondary heat exchanger via the intermediate medium heat exchange pipeline. The refrigerant on the second refrigerant pipeline flows through the final cooling first-stage heat exchanger, so that the refrigerant exchanges heat with the intermediate medium through the final cooling first-stage heat exchanger, and The fuel oil having the pre-cooling temperature flows through the final cooling secondary heat exchanger, so that the intermediate medium exchanges heat with the fuel oil through the final cooling secondary heat exchanger.

3. The fuel temperature control system according to claim 1, characterized in that: The first fuel pipeline includes a first low-temperature fuel pipeline and a first high-temperature fuel pipeline. The fuel from the fuel storage tank flows to the pre-cooling heat exchanger via the first high-temperature fuel pipeline, and the fuel heat-exchanged in the pre-cooling heat exchanger flows back to the fuel storage tank via the first low-temperature fuel pipeline.

4. The fuel temperature control system according to claim 1, characterized in that: The pre-cooling temperature is 2-5 degrees Celsius, and / or the target temperature is -40 degrees Celsius to -5 degrees Celsius.

5. A fuel preparation system, characterized in that: The fuel preparation system comprises: The fuel temperature control system according to any one of claims 1 to 4; A cold source device, used to provide refrigerant to the fuel temperature control system; a fuel storage tank for containing fuel, the fuel from the fuel storage tank being cooled to the precooling temperature by the precooling module; A collecting tank is provided, into which the fuel cooled by the pre-cooling module can flow from the fuel storage tank through the final cooling module at the target temperature.

6. The fuel preparation system according to claim 5, characterized in that: The fuel tank further includes a water adding module configured to add water to the fuel before the fuel in the fuel storage tank is cooled to the pre-cooling temperature by the pre-cooling module.

7. The fuel preparation system according to claim 6, characterized in that: The water adding module is configured to maintain the fuel temperature at 25-30 degrees Celsius through the cooling module during the water adding process.

8. A method for preparing fuel, characterized in that: The fuel preparation method is used in a fuel temperature control system according to any one of claims 1 to 4; the fuel preparation method comprises: Precooling step: Cooling the fuel in the fuel storage tank to a precooling temperature by a precooling module, wherein the precooling temperature is higher than the freezing point of water, wherein in the precooling module, the refrigerant flows through a precooling heat exchanger as a cold side, and the fuel from the fuel storage tank flows through the precooling heat exchanger as a hot side, thereby generating heat exchange; Final cooling step: cooling the fuel in the fuel storage tank to a target temperature lower than the pre-cooling temperature by a final cooling module, wherein in the final cooling module, the refrigerant flows through the final cooling heat exchanger as a cold side, and the fuel from the fuel storage tank flows through the final cooling heat exchanger as a hot side, thereby generating heat exchange; The final cooling step is performed after the pre-cooling step is completed.

9. The method according to claim 8, wherein Before performing the pre-cooling step, water is added to the fuel to obtain fuel with supersaturated water content.

10. The method according to claim 8, wherein The final cooling step includes allowing the fuel to flow into a collection tank at the target temperature.

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