CONDENSATION TRAIL GENERATION SYSTEM

Abstract

CONDENSATION TRAIL GENERATION SYSTEM The invention relates to a condensation trail generation system (2) comprising: - an evaporation chamber (21) having an inlet orifice (211) and an outlet orifice (213) and in which an airflow (F) flows in a flow direction (E), where said airflow (F) has a first temperature (T1) at the inlet orifice (211) and a second temperature (T2) at the outlet orifice (213), said second temperature (T2) being lower than the first temperature (T1); and - a water supply device (23) delivering pressurized water into said evaporation chamber (21). Implementing such a system makes it possible to artificially create a condensation trail at the outlet of the evaporation chamber by releasing a stream of hot air saturated with water vapor inside a cold evaporation chamber. Fig. 2

Description

Title of the invention: CONDENSATION TRAIL GENERATION SYSTEM technical field

[0001] The present invention relates to a system for generating an artificial contrail. The invention also relates to an aircraft comprising a hot air source and such a contrail generation system. PRIOR TECHNOLOGY

[0002] In order to reduce pollution caused by the use of kerosene in aircraft operation, aircraft are being developed with engines powered by other energy sources, particularly hydrogen. Specifically, hydrogen is used to power a fuel cell to generate an electric current which, in turn, drives the aircraft's engine. To simplify the description, a fuel cell is considered to comprise a plurality of fuel cells.

[0003] Although it is known that contrails from aircraft using combustion engines account for approximately 60% of aviation's impact on global warming, the impacts of contrails from electric motors powered by hydrogen fuel cells are still unknown. Indeed, it is currently not possible to fly a large-scale aircraft with a fuel cell and therefore to study the formation and evolution of contrails from such aircraft.

[0004] There is therefore a need to find a solution to simulate the formation and evolution of condensation trails from an aircraft, particularly in the case where the engines are powered by a fuel cell using dihydrogen. Description of the invention

[0005] An object of the present invention is to provide a system which makes it possible to artificially create a condensation trail.

[0006] To this end, a condensation trail generation system is proposed comprising:

[0007] - an evaporation chamber which has an inlet orifice and an outlet orifice and in which an airflow passes between said inlet orifice and said outlet orifice in a flow direction, where said airflow has a first temperature at the inlet orifice and a second temperature at the outlet orifice, said second temperature being lower than the first temperature; and

[0008] - a water supply device delivering pressurized water within said evaporation chamber.

[0009] The implementation of such a system makes it possible to artificially create a condensation trail at the outlet of the evaporation chamber by releasing a stream of hot air saturated with water vapor inside the cold evaporation chamber. When this air escapes the evaporation chamber and reaches the aircraft's exterior atmosphere, its humidity level increases to over 1500%, initiating the homogeneous nucleation process and the formation of ice crystals. These ice crystals then persist to form a condensation trail, which can be studied to assess its impacts on the climate. The system of the invention thus makes it possible to create artificial condensation trails that simulate the use of an engine.

[0010] Advantageously, said water supply device includes a vaporizer disposed in said evaporation chamber, near said air inlet orifice.

[0011] According to a particular aspect, said vaporizer comprises droplet spray nozzles, said droplets having a size of less than 50 pm.

[0012] According to another particular aspect, said nozzles spray between 5 and 30 g / s of liquid water into said evaporation chamber.

[0013] According to one particular aspect, said first temperature is greater than 200°C.

[0014] According to another particular aspect, said second temperature is less than 40°C.

[0015] According to yet another particular aspect, the airflow has a first percentage of humidity at the inlet orifice which is less than 25% and a second percentage of humidity at the outlet orifice which is greater than 75%.

[0016] According to a particular aspect, said evaporation chamber has an overall cylindrical shape and said inlet orifice and said outlet orifice are each disposed at one end of said evaporation chamber.

[0017] The invention also relates to an aircraft comprising a hot air source and a condensation trail generation system as described above, wherein said hot air source is connected to said inlet orifice of said evaporation chamber of said system.

[0018] According to a particular aspect, the aircraft comprises a propulsion system and said hot air source is a hot air outlet of said propulsion system. Brief description of the drawings

[0019] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of an example of implementation and its variants, the said description being made in relation to the attached drawings, among which:

[0020] [Fig. 1] is a side view of an aircraft according to the invention; and

[0021] [Fig.2] is a schematic view of a trail generation system condensation according to the invention.

[0022] DETAILED DESCRIPTION OF AN IMPLEMENTATION EXAMPLE

[0023] Fig. 1 shows an aircraft 1 which has a fuselage 11 on either side of which a wing 12 is fixed. Under each wing 12 is fixed at least one propulsion system 13.

[0024] By convention, X is called the longitudinal direction of aircraft 1, Y the transverse direction of aircraft 1 which is horizontal when aircraft 1 is on the ground, and Z the vertical direction or vertical height when aircraft 1 is on the ground, these three directions X, Y and Z being orthogonal to each other.

[0025] On the other hand, the terms "forward" and "rear" are to be considered in relation to a direction of advance of the aircraft 1 during the operation of the propulsion systems 13, this direction being schematically represented by arrow A.

[0026] In the embodiment of the invention presented here, the propulsion system 13 can take the form of a combustion engine comprising a propeller 131 mounted on the drive shaft of the combustion engine or of a jet engine.

[0027] According to the invention, the aircraft includes a condensation trail generation system 2. Preferably, the system 2 is fixed to the fuselage 11 and to the outside of the aircraft 2, as illustrated in [Fig. 1].

[0028] System 2, illustrated in more detail in [Fig. 2], comprises an evaporation chamber 21 which has an inlet orifice 211 and an outlet orifice 213. An airflow F flows into the evaporation chamber 21 (for example, at a speed of about 4 m / s) between the inlet orifice 211 and the outlet orifice 213 along a flow direction E. Preferably, the flow direction E of the airflow F is parallel to the direction of travel A of the aircraft 1. Even more preferably, the flow direction E of the airflow F is in the opposite direction to the direction of travel A of the aircraft 1 so that the airflow F escapes from the evaporation chamber 21 towards the rear of the aircraft 1. Furthermore, it is preferable that the condensation trail produced by system 2 escapes at a sufficient distance from the plumes generated by the propulsion systems 13 of aircraft 1.

[0029] The evaporation chamber 21 is configured to cool the airflow F as it passes through it, such that the airflow F has a first temperature T1 at the inlet orifice 211 and a second temperature T2 at the outlet orifice 213, the second temperature T2 being lower than the first temperature T1. The cooling of the airflow F in the chamber The evaporation 21 is mainly generated by the energy loss resulting from the vaporization of pressurized water from the water supply device 23 (described below). The evaporation chamber 21 is preferably insulated from the outside atmosphere by a layer of insulating material.

[0030] The system 2 further comprises a water supply device 23 which delivers pressurized water into the evaporation chamber 21. The water supply device 23 saturates the airflow F flowing into the evaporation chamber 21 with humidity. The thermal energy supplied at the inlet of the evaporation chamber 21 (airflow F at temperature Tl) is used for the vaporization of the pressurized water in the water supply device 23.

[0031] In this way, it is possible to artificially create a condensation trail at the outlet of the evaporation chamber 21.

[0032] More specifically, system 2 of the invention aims to release a plume of warm air saturated with water vapor into a cold atmosphere (i.e., the airflow F within the evaporation chamber 21). When this plume escapes from the evaporation chamber 21 and reaches the external atmosphere of the aircraft 1, which has very cold temperatures under flight conditions (for example, approximately -40°C at 25,000 feet), its humidity level will increase to over 1500%. Such conditions allow the homogeneous nucleation process and the formation of ice crystals to begin. Thus, if atmospheric conditions, in terms of temperature and humidity, are favorable, these ice crystals will persist in a region known as "ice supersaturated" to form a persistent condensation trail, which can then be studied to assess its impacts on the climate.These atmospheric conditions, for example, meet the Schmidt-Appleman criterion.

[0033] Thus, system 2 of the invention makes it possible to form artificial contrails that simulate the use of an engine (whether it be an electric motor powered by a hydrogen fuel cell or a combustion engine). These artificial contrails can be studied and adapted so as to reduce, in the long term, the risks and impacts of such engines before their large-scale use by aircraft.

[0034] In particular, system 2 of the invention can make it possible to create, that is to say emulate, condensation trails generated by a dihydrogen combustion engine or a fuel cell using dihydrogen.

[0035] System 2 of the invention can also be attached to any type of aircraft.

[0036] In this example, the water supply device 23 includes a vaporizer 231 disposed in the evaporation chamber 22. More specifically, the vaporizer 231 is disposed near the air inlet orifice 211 and downstream of the latter.

[0037] The vaporizer 231 disperses liquid water into the evaporation chamber 21 in the form of fine droplets to promote water vaporization. Optimal water vaporization promotes the initiation of the homogeneous nucleation process and the formation of ice crystals. The water supply device 23 therefore provides a means for vaporizing a flow of water into microdroplets.

[0038] In this example, liquid water is stored under pressure in a tank 237 which may, for example, have a capacity of approximately 160 liters. The water stored in the tank 237 is pressurized by nitrogen cylinders 239 (two cylinders here with a pressure of, for example, approximately 2400 psi) which regulate the pressure within the tank 237 and up to its distribution in the evaporation chamber 21 via the vaporizer 231.

[0039] In this example, the vaporizer 231 includes nozzles 233 for spraying water droplets 235. These nozzles 233 (three in this example) allow for the spraying of droplets 235 with a size less than 50 µm. This is therefore a microdroplet spray. Such a droplet size 235 promotes water vaporization. The droplet size 235 is controlled by using high-pressure fracturing nozzles 233 and a water pressure between 500 and 1500 psi.

[0040] In addition, the droplets 235 are preferably sprayed in the form of a cone which must not hit the walls of the evaporation chamber 21. Thus, the vaporization of the water is further promoted.

[0041] Preferably, and in order to further optimize the vaporization of the water, the nozzles 233 spray between 5 and 30 g / s of liquid water into the evaporation chamber 21.

[0042] As previously stated, the evaporation chamber 21 cools the airflow F passing through it. Preferably, the first temperature Tl of the airflow F at the inlet orifice 211 is greater than 200°C and less than 220°C. Even more preferably, the first temperature Tl is approximately 220°C. The quantity of air injected at the inlet orifice 211 is approximately 220 g / s, and the air is injected at a velocity of approximately 35 m / s.

[0043] Preferably, the second temperature T2 of the airflow F at the outlet orifice 213 is less than 40°C, and in particular between 30°C and 40°C, the atmospheric temperature at the outlet orifice 213 being on the order of -40°C. Even more preferably, the second temperature T2 is about 34°C and the air escapes from the evaporation chamber 21 at a speed of about 15 m / s.

[0044] Furthermore, the airflow F preferably has a first percentage of humidity at the inlet orifice 211 that is less than 25%. Thanks to the spraying of droplets 235 in the evaporation chamber 21, the airflow F has a second percentage of humidity at outlet orifice 213 which is preferably greater than 75%, and which can be equal to 100%.

[0045] It is understood that system 2 includes a plurality of sensors which allow, in particular, the measurement of air flow, temperature, pressure and humidity level upstream and inside the evaporation chamber as well as at the outlet of the evaporation chamber 21. System 2 may also include a control panel for displaying these measurements and a control unit for controlling the supply of hot air into the evaporation chamber as well as the supply of water within the evaporation chamber 21.

[0046] According to the embodiment illustrated in Figs. 1 and 2, the evaporation chamber 21 has a generally cylindrical shape. Furthermore, the inlet orifice 211 and the outlet orifice 213 are each located at one end 215, 217 of the evaporation chamber 21. Preferably, the evaporation chamber 21 extends parallel to the longitudinal axis X of the aircraft 1. This shape optimizes the aerodynamics of the system 2, thereby limiting the turbulence generated by the system 2.

[0047] According to a particular example, the evaporation chamber has an internal diameter of approximately 50 cm and a length between the inlet orifice 211 and the outlet orifice 213 of approximately 550 cm. The outlet orifice 213 preferably has a cylindrical shape with a diameter of approximately 25 cm.

[0048] As illustrated in [Fig. 1], the system 2 can be mounted on an aircraft 1. The aircraft 1 then includes a hot air source which is connected to the inlet orifice 211 of the evaporation chamber 21 of the system 2. This hot air source is configured to supply the evaporation chamber 21 with air whose temperature is overall equal to the first temperature T1 of the airflow F. It is this hot air which is used by the evaporation chamber 21 to form the condensation trail.

[0049] Preferably, the hot air source is a hot air outlet from the propulsion system 13 of the aircraft 1. The propulsion system 13 is, for example, a combustion engine, such as a kerosene or hydrogen engine. Thus, it is possible to use the hot air created by the combustion engine to supply the condensation trail generation system 2. Alternatively, the hot air source may comprise an air source and an electrical power source arranged at the outlet of the air source and configured to heat the air from the air source, in order to supply the evaporation chamber 21 with air whose temperature is overall equal to the first temperature Tl of the airflow F.

Claims

Demands

1. System (2) for generating a condensation trail, said system (2) comprising: - an evaporation chamber (21) which has an inlet orifice (211) and an outlet orifice (213) and in which an airflow (F) flows between said inlet orifice (211) and said outlet orifice (213) in a flow direction (E), wherein said airflow (F) has a first temperature (T1) at the inlet orifice (211) and a second temperature (T2) at the outlet orifice (213), said second temperature (T2) being lower than the first temperature (T1); and - a water supply device (23) delivering pressurized water into said evaporation chamber (21).

2. System (2) according to claim 1, characterized in that said water supply device (23) comprises a vaporizer (231) disposed in said evaporation chamber (22), near said air inlet orifice (211).

3. System (2) according to claim 2, characterized in that said vaporizer (231) comprises droplet (233) spray nozzles (235), said droplets (235) having a size less than 50 pm.

4. System (2) according to claim 3, characterized in that said nozzles (233) spray between 5 and 30 g / s of liquid water into said evaporation chamber (21).

5. System (2) according to any one of claims 1 to 4, characterized in that said first temperature (Tl) is greater than 200° C.

6. System (2) according to any one of claims 1 to 5, characterized in that said second temperature (T2) is less than 40°.

7. System (2) according to any one of claims 1 to 6, characterized in that the airflow (F) has a first percentage of humidity at the inlet orifice (211) which is less than 25% and a second percentage of humidity at the outlet orifice (213) which is greater than 75%.

8. System (2) according to any one of claims 1 to 7, characterized in that said evaporation chamber comprises a in overall cylindrical shape and in that said inlet orifice (211) and said outlet orifice (213) are each disposed at one end (215, 217) of said evaporation chamber (21).

9. Aircraft (1) comprising a hot air source and a condensation trail generation system (2) according to any one of claims 1 to 8, wherein said hot air source is connected to said inlet port (211) of said evaporation chamber (21) of said system (2).

10. Aircraft (1) according to claim 9, characterized in that it comprises a propulsion system (13) and in that said hot air source is a hot air outlet of said propulsion system (13).

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