Patent ID: 12202609

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

For the sake of illustration and clarity, scales and proportions are not strictly adhered to in the drawings. Moreover, identical, similar, or analogous elements are denoted using the same reference signs throughout the drawings.

FIG.1schematically shows an air conditioning system9for a cabin10of an aircraft8, comprising an air cycle turbine engine12that comprises a compressor13and an expansion turbine14mechanically coupled to one another by a mechanical shaft19. This mechanical shaft19also drives a fan18which forms an energy-consuming wheel, the role of which is described below.

The compressor13comprises an air inlet13aconnected to a device for bleeding air from an air source (not shown in the drawings for the sake of clarity) by means of a primary cooling exchanger, also referred to as PHX (for primary heat exchanger) exchanger15throughout the following, and a pipe20fluidically connecting the air bleed device and the PHX exchanger15.

In other words, the air from the air bleed device, which is for example a device for bleeding air from a compressor of a propulsion engine of the aircraft or a device for bleeding air from a compressor of an auxiliary engine of the aircraft, or a device for drawing air from a scoop of the aircraft, whether or not associated with an intermediate compressor, supplies the compressor13of the air cycle turbine engine12after passing through a primary PHX exchanger15. This PHX exchanger15comprises a hot pass formed by the air fed from the air bleed device via the pipe20, and a cold pass supplied with air at ram pressure, which circulates in a channel22for the circulation of ram air, hereinafter referred to as the ram-air channel.

The ram-air circulation in the ram-air channel22is provided by the fan18mounted on the shaft18of the air cycle turbine engine, which shaft extends into the ram-air channel22. According to other alternatives, the fan18can be separate from the shaft19and rotated by an independent electric motor.

The compressor13also comprises an air outlet13bfluidically connected to a main cooling exchanger, also referred to by the acronym MHX (main heat exchanger)16throughout the following, which is arranged in the channel22for the circulation of ram air drawn from outside the aircraft.

This MHX exchanger16comprises a hot primary circuit supplied with the air flow from the compressor13, and a cold secondary circuit, in thermal interaction with the primary circuit, supplied with the ram air circulating in the ram-air channel22. In other words, the air from the compressor13is cooled, in the MHX exchanger16, by the ram air circulating in the ram-air circulation channel22.

The expansion turbine14of the air cycle turbine engine12comprises an air inlet14asupplied with air from the MHX exchanger16having passed through a water extraction loop30, which will be described below, and an air outlet14bthat is connected to said cabin10in order to be able to supply said cabin with air at a controlled pressure and temperature.

The water extraction loop30comprises, according to the embodiment of the drawings, a heater31comprising a primary air circuit supplied with air from the main MHX exchanger16, in thermal interaction with a secondary circuit that is supplied with air from a water extractor33and is intended for supplying the inlet14aof the expansion turbine.

The water extraction loop30also comprises a condenser31comprising a primary air circuit supplied with the air flow at the outlet of the heater31, in thermal interaction with a secondary air circuit supplied with the air flow from the expansion turbine14, to allow condensation of the air flow of the primary circuit.

Finally, the water extraction loop also comprises a water extractor33that is arranged at the outlet of the condenser32and is designed to be able to recover the water condensed by the condenser and feed said water to a water distribution pipe26(shown schematically as a dotted line inFIGS.1and2).

This water distribution pipe26, also referred to throughout the text as spray pipe, extends between the water extractor33and the ram-air channel22, upstream of the main MHX exchanger16, in order to be able to spray the water recovered by the water extractor33into the ram-air flow of the ram-air channel22.

FIG.2shows another embodiment of the invention. The main difference from the embodiment ofFIG.1relates to the air cycle turbine engine12. InFIG.2, the turbine engine12only has the expansion turbine14and the fan18mounted on the shaft19. In other words, according to this embodiment, the turbine engine12does not comprise a compressor mounted on the mechanical shaft19. In addition and according to this embodiment, the air from the air bleed device (not shown in the drawings) directly supplies the main MHX exchanger16via the pipe20(which therefore no longer connects the air bleed device to the PHX exchanger15as for the embodiment ofFIG.1, but connects said device to the main MHX exchanger16directly). This embodiment therefore also does not have a primary PHX exchanger15. The air which supplies the main MHX exchanger16is therefore, according to this embodiment, air that is already compressed. This air is, for example, air bled from a propulsion engine of an aircraft or air treated by an upstream compressor.

Whatever the embodiment considered (turbine engine with compressor or without compressor), the air conditioning system according to the invention also comprises means40for heating the spray water flowing in the spray pipe26. These means40for heating the spray water are formed, for example and as shown inFIG.1, of a heat exchanger, referred to as the spray exchanger, comprising a cold circuit supplied with water from the spray pipe26and a transverse hot circuit26bsupplied with a source of hot fluid. This hot circuit26bcan be of any type. It may for example be a bypass of a fuel circuit supplying a propulsion engine of the aircraft, or a bypass of an oil circuit for lubricating an engine part of the aircraft or a bypass of an air circuit of the air conditioning system of the aircraft. Any type of heat exchanger for a hot fluid and a cold liquid fluid can be used to form the means40for heating the spray water.

In general, this hot circuit can be selected according to the design of the air conditioning system and the ease of diverting a hot circuit to form the hot pass of the spray exchanger.

The presence of such a spray exchanger on the spray pipe26therefore allows the water circulating in the spray pipe26to be heated and therefore the efficiency of the evaporation of the water in the ram-air channel22to be optimized. This helps in particular to make it possible to lower the temperature of the ambient air circulating in the ram-air channel22and therefore to improve the cooling of the air from the compressor13, which air forms the hot pass of the MHX exchanger16. The water heated by the heating means40evaporates more quickly and completely in the ram-air channel22.

According to a particular embodiment and as shown inFIGS.3and4, the heating means40are integrated into the MHX exchanger16.

To this end, the MHX exchanger16comprises a plurality of parallel plates51which are placed one on top of the other and which alternately define therebetween primary channels60and secondary channels80, i.e., each primary channel60is nested between two secondary channels80. Preferably, the first channel starting from the bottom of the exchanger is a secondary channel80, on top of which a transverse primary channel60is placed, on top of which a second secondary channel80is placed, on top of which a second transverse primary channel is placed, and so on, until the last channel, which is preferably also a secondary channel. Of course, the stacking order of the channels can be different without changing the principle of the invention.

Each primary channel60has, according to the embodiment ofFIGS.3and4, a general U shape and extends between a primary air inlet61and a primary air outlet62. Each leg of the U extends in a primary direction P, as shown inFIGS.3and4by the axis system (P, S, V), where P represents the primary direction, S represents the secondary direction and V represents the vertical defined by gravity.

Each secondary channel80extends between a secondary air inlet81and a secondary air outlet82in the secondary direction S.

In other words, the primary channels60and the secondary channels80are generally perpendicular to each other and nested in pairs so as to form heat exchange regions at each interface of a secondary channel with a leg of the primary channel.

Each primary channel60is further delimited by closure bars63, also referred to as primary closure bars, which interconnect the parallel plates51and extend on each side of the primary channel60in the primary direction P.

Each secondary channel80is also delimited by closure bars83, also referred to as secondary closure bars, which interconnect the parallel plates and extend on each side of the secondary channel80, in the secondary direction S.

The primary closure bars63extend between a primary water inlet63aand water-spray openings63b. In addition, each primary closure bar63comprises an internal channel which extends in the primary direction P, leading into the water inlet63aand fluidically connecting the micro-perforations formed by the spray openings63b. Thus, the water which supplies the inlet63aof the closure bars63is sprayed through the spray openings63binto the air flow which feeds the secondary channels80.

The secondary closure bars83extend between a secondary water inlet83aand a secondary water outlet83b. The closure bars83are arranged in the vicinity of the primary air outlets62such that the water which supplies the inlet83aof each closure bar is heated by the air which circulates in the primary channels60.

The exchanger according to the embodiment of the drawings further comprises a water collector90into which the outlets83bof all the secondary closure bars83lead.

The exchanger according to the embodiment of the drawings also comprises a water distributor95which is fluidically connected to the water collector90by a hose (not shown in the drawings for the sake of clarity) that leads into the water inlets63aof the primary closure bars63.

Thus, all the water collected by the collector90and heated by the heat exchanges between the secondary closure bars83and the primary channels60is distributed in the primary closure bars63such that this heated water can be sprayed into the secondary air flow which supplies the exchanger.

The exchanger according to this embodiment also comprises a common primary air inlet66leading into the primary air inlets61of the primary channels60, and a common air outlet67for primary air into which the primary air outlets62of the primary channels60lead.

The general operating principle of exchanger16is therefore as follows. Hot air from an air bleed device of an aircraft supplies the inlet66of the exchanger. This hot air is then distributed to the primary channels60. Within each U-shaped channel60, the hot air circulates in a leg of the U in the primary direction P, turns around at a rounded connection piece connecting the two parallel legs of the U, then circulates in the opposite direction in the primary direction P so as to lead into the air outlet62which supplies the common primary air outlet67.

In addition, cold air, from a draw of air from outside the aircraft, supplies the air inlets81of the primary channels80. This air circulates in the secondary channels80, which extend in the secondary direction S, so as to exit through the outlets82.

Since the primary channels60are nested together with the secondary channels80, heat exchanges take place between the flow of hot air and the flow of cold air such that the air flow which leaves the common outlet67is cooled compared with the inlet air.

At the same time, water is injected into the inlets83aof the secondary closure bars. This water comes from a water extraction loop of an air conditioning system as shown schematically inFIGS.1and2.

This water is heated by heat exchanges between the secondary closure bars and the primary air flow. This heated water is collected by the water collector90which is connected to the water distributor95. This heated water is therefore sprayed into the flow of cold air which supplies the secondary channels80.

This increase in water temperature therefore makes it possible to accelerate the evaporation time and therefore to limit the path that is necessary between the water spraying and the inlet of the exchanger.

An air conditioning system according to this embodiment is therefore particularly effective insofar as it allows better cooling of the air while greatly limiting the size of the system.