Patent Description:
The aerosol generating device according to the invention is configured to operate with a consumable article comprising for example a solid substrate, also known as aerosol forming substrate, able to form aerosol when being heated. Thus, such type of aerosol generating devices, also known as heat-not-burn devices, is adapted to heat, rather than burn, the substrate by conduction, convection and/or radiation, to generate aerosol for inhalation.

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm vaporizable substances as opposed to burning tobacco in conventional tobacco products.

Some aerosol generating devices of this type are known for example from <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

A commonly available reduced-risk or modified-risk device is an aerosol generating device known as a heat-not-burn device. Devices of this type generate aerosol or vapour by heating an aerosol forming substrate (usually a solid substrate) that typically comprises moist leaf tobacco or other suitable vaporizable material to a temperature typically in the range <NUM> to <NUM>. Heating an aerosol substrate, but not combusting or burning it, releases aerosol that comprises the components sought by the user but not the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other vaporizable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user.

Regardless of the heating method used to heat a solid substrate, great care is taken to ensure even heating of the substrate. Particularly, it is known that if a tobacco containing substrate is heated too much, harmful chemicals may develop. If the temperature is too low, flavour and aerosol quantity are too low, hence reducing user experience. It is thus important to evenly heat the tobacco containing substrate at just the right temperature.

According to the prior art, this has been primarily achieved by focusing on the design of the heating element as well as the heating profile used to heat the substrate. This can be complicated and not optimal. For example, in the prevailing tobacco stick consumables, air is drawn in the bottom of the stick, even though this may not be the optimal design.

One of the aims of the invention is to provide an aerosol generating device allowing evenly heating of a solid substrate without using complex design of the heating element or special heating profiles.

For this purpose, the invention, as defined in claim <NUM>, relates to an aerosol generating device configured to operate with a consumable article comprising a substrate portion containing a solid substrate and defining an external surface;.

Particularly, it was observed that in case of a single air inlet arranged in traditional aerosol generating devices in a centre bottom portion of the heating chamber, a cool zone is formed in the substrate portion of the consumable article near the corresponding inlet since the total quantity of fresh air passes through this zone. In this cool zone, the tobacco remains unconsumed. On the contrary, in a top portion of the substrate portion or in a portion immediately adjacent to a heating element, an overheated zone is usually formed. In this overheated zone, the tobacco may be burnt. Creating an airflow gradient toward the common border (i.e. a greater airflow in the periphery region of the substrate in comparison with its central region) makes it possible to counter this effect. Thus, cooling effect in the centre bottom portion of the substrate portion is reduced and heat may be more evenly distributed throughout this substrate portion.

According to some embodiments, said inlet portion extends:.

Arranging an air inlet portion close to a common border of the bottom and lateral walls of the heating chamber forces air entering in the periphery region of the substrate. Thus, an airflow gradient is created between the periphery and central regions.

According to some embodiments, said inlet portion comprises a plurality of inlet holes.

Thanks to these features, air can enter through several air inlets holes. Thus, contrary to a single air inlet case, only a part of the fresh air can pass through the corresponding inlet zone. This reduce cooling effect in the inlet zone.

According to some embodiments, the inlet portion extends on the bottom wall.

According to some embodiments, the concentration and/or the dimensions of the inlet holes increase(s) from the centre of the bottom wall to the common border.

Thanks to these features, a greater airflow is created in the periphery region of the substrate. Thus, an airflow gradient is created between the periphery and central regions.

According to some embodiments, the inlet holes are arranged symmetrically in respect with the centre of the bottom wall.

According to some embodiments, the inlet portion extends on the or at least one lateral wall.

According to some embodiments, at least two inlet holes are arranged according to the chamber axis, preferably homogeneously according to the chamber axis.

Thanks to these features, a better heat distribution inside the substrate portion of consumable article can be achieved.

According to some embodiments, the inlet portion extends on a unique lateral wall forming a cylindrical wall.

According to some embodiments, at least two inlet holes are arranged to face each other.

According to some embodiments, a plurality of inlet holes are arranged circumferentially on said cylindrical wall.

Thanks to these features, inlet holes can be arranged symmetrically in respect with a central axis passing through the device. This ensures more homogeneous heat distribution inside the substrate portion of the consumable article.

According to some embodiments, the substrate portion of the consumable article is wrapped in a wrapper, the wrapper comprising a plurality of openings;
the inlet hole of the inlet portion being arranged to face said openings.

Thanks to these features, air can enter from the corresponding air inlet holes of the device directly inside the substrate portion of the consumable article, without passing through the wrapper. This ensures a better airflow throughout the consumable article and consequently, better aerosol generation.

According to some embodiments, the heating chamber comprises several inlet portions.

According to some embodiments, at least one inlet portion extends on the bottom wall and at least one inlet portion extends on the or at least one lateral wall.

Thanks to these features, inlet holes can be arranged on both bottom and at least one lateral walls. This can further improve heat transfer inside the substrate portion of consumable article.

According to some embodiments, the heating chamber further defines an open end opposite to the bottom wall.

Thanks to these features, the consumable article can be inserted at least partially in the heating chamber.

According to some embodiments, the or each inlet portion forms a unique air permeable portion on the corresponding contact wall.

Thanks to these features, the airflow inside the consumable article can be better controlled and predicted.

According to some embodiments, the or at least one inlet hole is arranged adjacent to the common border.

Thanks to these features, it is possible to achieve a more even air distribution inside the substrate portion of the consumable article.

As used herein, the term "aerosol generating device" or "device" may include a vaping device to deliver an aerosol to a user, including an aerosol for vaping, by means of a heating element explained in further detail below. The device may be portable. "Portable" may refer to the device being for use when held by a user. The device may be adapted to generate a variable amount of aerosol, e.g. by activating the heater element for a variable amount of time (as opposed to a metered dose of aerosol), which can be controlled by a trigger. The trigger may be user activated, such as a vaping button and/or inhalation sensor. The inhalation sensor may be sensitive to the strength of inhalation as well as the duration of inhalation to enable a variable amount of vapour to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.). The device may include a temperature regulation control to drive the temperature of the heater and/or the heated aerosol generating substance (aerosol pre-cursor) to a specified target temperature and thereafter to maintain the temperature at the target temperature that enables efficient generation of aerosol.

As used herein, the term "aerosol forming substrate" or "substrate" may refer to a material which may for example comprise nicotine or tobacco or any other smokable material, and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol former may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

As used herein, the term "aerosol" may include a suspension of aerosol forming substrate as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to/include a vapour. Aerosol may include one or more components of the aerosol forming substrate.

An aerosol generating device <NUM> according to the invention is shown on <FIG>. This aerosol generating device <NUM> is designed to operate with a consumable article <NUM> also shown on this Figure.

Particularly, as it is shown on <FIG>, the consumable article <NUM> comprises a substrate portion <NUM> and a filter portion <NUM>. Both portions <NUM>, <NUM> can be wrapped using a unique wrapper <NUM> attaching these portions together. In other examples, the portions <NUM>, <NUM> may be wrapped by different wrappers and fixed one to the other by any other suitable mean. The or each wrapper <NUM> may, for example, comprise paper and/or non-woven fabric and/or aluminium. The or each wrapper <NUM> may be porous or air impermeable. Advantageously, according to the embodiments explained below, the or each wrapper <NUM> is air impermeable. Additionally, according to these embodiments, the or each wrapper <NUM> wraps the corresponding portions <NUM>, <NUM> only circumferentially. This means that the corresponding ends of the portions <NUM>, <NUM> can be unwrapped. The consumable article <NUM> can have a generally tubular shape defining for example a circular or elliptical cross-section. According to another example, the consumable article <NUM> defines a rectangular cross-section.

The substrate portion <NUM> contains an aerosol forming substrate intended to be heated by a heating chamber of the aerosol generating device <NUM> as it will be explained in further detail below. According to the invention, the aerosol forming substrate comprises a solid substrate. As mentioned above, the solid substrate can comprise shredded tobacco. The shredded tobacco can be advantageously substantially aligned along the direction of extension of the consumable article <NUM>. Additionally, according to some examples, the substrate portion <NUM> may comprise one or several susceptors integrated into the aerosol forming substrate. The susceptors may be formed from electrical conductor materials able to generate eddy currents when placed within a magnetic field. Eddy currents cause the susceptors to generate heat suitable for heating the aerosol forming substrate to generate aerosol. The magnetic field can be generated by a coil comprised in a heating system of the aerosol generating device <NUM>. The substrate portion <NUM> may comprise two or more adjacent segments with at least an upstream segment containing an aerosol forming substrate and a downstream segment forming spacer or cooling segment. The downstream segment can be a tube, for example, made of paper or other rigid material such as PLA material. The tube may be hollow or partially filled or reinforced by internal, e.g. radial and/or longitudinal, walls.

The filter portion <NUM> comprises a core acting for example like a filter. The core may for example be a foam, or packed strands or fibres. In some examples, the filter portion <NUM> can form a mouthpiece intended to be in contact with the user's lips and/or mouth while using the device <NUM>. In some other examples, the filter portion <NUM> can be inserted into a separate mouthpiece intended to be in contact with the user's lips and/or mouth. According to some other examples, the consumable article <NUM> can comprise only the substrate portion <NUM>.

The aerosol generating device <NUM> comprises a housing <NUM> defining an insertion opening <NUM> suitable for insertion of the consumable article <NUM>. The housing <NUM> delimits an internal space of the device <NUM> receiving various elements designed to carry out different functionalities of the device <NUM>. This internal space can for example receive a battery <NUM> for powering the device <NUM>, a control module <NUM> for controlling the operation of the device <NUM>, and a heating chamber <NUM> configured to receive and heat at least a part of the consumable article <NUM>. Among these elements, only the heating chamber <NUM> will be explained in further detail. The other elements, as for example the battery <NUM> and the control module <NUM>, can be implemented using known techniques.

The heating chamber <NUM> extends along a chamber axis X between a closed end <NUM> and an open end <NUM>, and has substantially the same cross-sectional shape as the consumable article <NUM>. The open end <NUM> opens to the insertion opening <NUM> of the housing <NUM>. As it is shown on <FIG>, the heating chamber <NUM> is adapted to receive the substrate portion <NUM> of the consumable article <NUM> through the open end <NUM> so as this substrate portion <NUM> extends inside the heating chamber <NUM> along the chamber axis X. Additionally, as mentioned above, the heating chamber <NUM> is adapted to heat at least a part of the substrate portion <NUM>.

For this purpose, the heating chamber <NUM> comprises a heating element <NUM> which is formed in the example of <FIG> by a heating blade. Such a heating blade is configured to penetrate inside the substrate portion <NUM> of the consumable article <NUM> while its insertion. The operation of the heating element <NUM> may be controlled by the control module <NUM> using control methods known per se.

The heating chamber <NUM> comprises a plurality of contact walls designed to be in contact with an external surface of the substrate portion <NUM> of the consumable article <NUM>. In the example of <FIG>, this external surface is formed by the part of the wrapper <NUM> received in the heating chamber <NUM> and the unwrapped end of the substrate portion <NUM>. The contact walls comprises a bottom wall <NUM> arranged substantially perpendicularly to the chamber axis X and at least one lateral wall <NUM> arranged substantially parallel to the chamber axis X. The bottom wall <NUM> is in contact with the or each lateral wall <NUM> along a common border <NUM> and defines a centre C. The heating element <NUM> extends from the centre C according to the chamber axis X. The centre C of the bottom wall <NUM> is defined as a geometrical centre of this wall which can be determined according to the shape of the bottom wall <NUM>. For example, when the bottom wall <NUM> has a circular shape, the centre C is the centre of the circle forming this shape. When the bottom wall <NUM> has a rectangular shape, the centre C is the intersection point of its diagonals. When the bottom wall <NUM> has a more complicated shape, the centre C can be defined as the centre of mass of the corresponding shape.

In the example of <FIG>, the heating chamber <NUM> defines generally tubular shape having for example a circular cross-section. In this, case a single lateral wall <NUM> is arranged parallel to the chamber axis X. Additionally, in the example of <FIG>, the lateral wall <NUM> of the heating chamber <NUM> is in contact with the wrapper <NUM> whereas the bottom wall <NUM> is in contact with the unwrapped end of the substrate portion <NUM>.

According to the invention, the heating chamber <NUM> further comprises an inlet portion comprising at least one inlet hole making it possible air entering inside the substrate portion <NUM> of the consumable article <NUM>. The or each inlet hole is in fluid communication with one or several air inlets arranged for example in the housing <NUM> of the device <NUM>. Thus, at least one airflow path is formed inside the housing <NUM> and extends through the substrate portion <NUM> of the consumable article <NUM> when it is received in the heating chamber <NUM> and when the device <NUM> is operated to generate aerosol. According to different embodiments of the invention explained in further detail below, the inlet portion extends on the bottom wall <NUM> and/or on the or at least one lateral wall <NUM> to create an airflow gradient at least at a region of the heating chamber <NUM> adjacent to this inlet portion. The airflow gradient extends from the centre C of the bottom wall <NUM> until the common border <NUM>.

Particularly, by "airflow gradient", it is understood a change of airflow (i.e. airflow rate) between at least two different points of the substrate portion <NUM> when it is received in the heating chamber <NUM> and the device <NUM> is operated to generate aerosol. According to the invention, such an airflow gradient extends from the centre C of the bottom wall <NUM> until the common border <NUM> which means that a greater airflow is generated in regions adjacent to the or at least one lateral wall <NUM> than an airflow generated in regions adjacent to the heating element <NUM>. In order to achieve such a gradient, several embodiments are possible.

A detailed view of the bottom wall <NUM> according to the first embodiment of the invention is shown on <FIG>.

Particularly, according to the first embodiment of the invention, the heating chamber <NUM> comprises an inlet portion <NUM> which extends on the whole bottom wall <NUM> of the heating chamber <NUM> and defines a plurality of inlet holes. In order to ensure an airflow gradient extending from the centre C until the common border <NUM>, the concentration and/or the dimensions of the inlet holes increase from the centre C of the bottom wall <NUM> to the common border <NUM>. The holes can be arranged for example symmetrically in respect with the centre C.

In the example of <FIG>, the bottom wall <NUM> has a circular shape. In the examples A), D), and G) of this Figure, the holes formed in the inlet portion <NUM> has a circular shape with a diameter increasing from the centre C until the common border <NUM>. In the example C) of this Figure, the circular holes have a same diameter but their number is greater near the common border <NUM> than near the centre C. In the examples B) and E) of this Figure, the holes extend according to several circumferential directions and are comprised within one or several arcs. Thus, their area increases from the centre C to the common border <NUM>. Finally, in the example F) of this Figure, the holes have a rectangular shape oriented toward the centre C. Of course, other hole arrangements and/or shapes can be applied.

A detailed view of a part of the heating chamber <NUM> according to the second embodiment of the invention is shown on <FIG>.

Particularly, according to the second embodiment of the invention, the heating chamber <NUM> comprises an inlet portion which extends on the bottom wall <NUM> according to each transversal direction Y perpendicular to the chamber axis X and passing through the centre C of the bottom wall <NUM>, from the common border <NUM> until <NUM>/<NUM> of the total length L1 of the bottom wall <NUM> according to this direction Y. Additionally, the length L1 of the bottom wall <NUM> according to a transversal direction Y passing through the centre C is measured along its surface which is in contact with the external surface of the consumable article <NUM>. In other words, this length L1 does not include the eventual thickness of one or several lateral walls <NUM>. In the example of <FIG>, the length L1 is measured between the internal surfaces of the lateral wall <NUM> which are intended to be in contact with the wrapper <NUM> of the consumable article <NUM>. It is also clear that when the bottom wall <NUM> has a circular shape, the length L1 according to each transversal direction Y presents the same value.

According to the example of <FIG>, a circumferential inlet portion <NUM> adjacent to the common border <NUM> is formed around the heating element <NUM>. When the bottom wall <NUM> presents a non-circular shape, the inlet portion <NUM> is defined as a peripheral zone adjacent to the common border <NUM> and extending according to each transversal direction Y passing through the centre C until <NUM>/<NUM> of the total length L1 of the bottom wall <NUM> according to this direction Y. For example, the inlet portion <NUM> can be symmetric in respect with the centre C of the bottom wall <NUM>.

The inlet portion <NUM> comprises at least one inlet hole making it possible air entering inside the substrate portion <NUM> of the consumable article <NUM>. The or each inlet hole is in fluid communication with one or several air inlets arranged for example in the housing <NUM> of the device <NUM>. Thus, at least one airflow path is formed inside the housing <NUM>. When the substrate portion <NUM> is received in the heating chamber <NUM>, the or each airflow path extends through this substrate portion <NUM> and through the filter portion <NUM> of the consumable article <NUM> until the non-wrapped end of the filter portion <NUM>. Several airflow paths inside the substrate portion <NUM> are shown in the example of <FIG>. Advantageously, according to the invention, said inlet hole(s) is(are) the unique opening(s) formed in the walls of the heating chamber <NUM>.

In the example of <FIG>, the inlet portion <NUM> comprises two triplets of inlet holes 52A, 52B arranged for example on either side of the heating element <NUM> according to the same transversal direction Y. In each triplet, the inlet holes can for example be homogeneously along said transversal direction Y. According to another example, the inlet portion <NUM> can comprise for example only one inlet hole which can have a greater diameter than the inlet holes of the triplets 52A, 52B. According to still another example, the inlet portion <NUM> can define a plurality of inlet holes arranged according to one or several circumferential directions. Along the corresponding circumferential direction, the inlet holes can for example be arranged homogeneously. According to still another example, the inlet portion <NUM> can define a plurality of inlet holes arranged symmetrically in respect with the centre C of the bottom wall <NUM>. According to still another example, one or several inlet holes can be arranged adjacent to the common border <NUM>. According to still another example, the second embodiment can be combined with the first embodiment. Particularly, in this case, the inlet portion <NUM> as defined in relation with the second embodiment, can comprise a plurality of holes those dimensions and/or concentration increase(s) from an internal border surrounding the centre C to the common border <NUM>. In this case, the holes can be formed/arranged as shown in the examples of <FIG> where a central region is excluded from the corresponding inlet portion. Of course, other examples of inlet holes arrangement and their number are still possible.

Additionally, it is clear that when the inlet holes are formed in the bottom wall <NUM> of the heating chamber <NUM> and the corresponding end of the substrate portion <NUM> is unwrapped, no additional opening is necessary on the wrapper <NUM>. In some cases, the wrapper <NUM> may comprise openings which may be closed by the lateral wall <NUM> of the heating chamber <NUM> when the substrate portion <NUM> is inserted therein.

<FIG> shows an example of the heating chamber <NUM> according to the third embodiment of the invention.

Particularly, according to the third embodiment of the invention, the heating chamber <NUM> comprises at least one inlet portion which extends on the or at least one lateral wall <NUM>, according to the chamber axis X, from the common border <NUM> until <NUM>/<NUM> of the total length L2 of this lateral wall according to this axis X. As in the previous case, the length L2 of the or at least one lateral wall is measured along to its surface which is in contact with the external surface of the consumable article <NUM>. In other words, in the example of <FIG>, the length L2 is measured along the chamber axis X between the bottom wall <NUM> and the open end <NUM> of the heating chamber <NUM>.

In the example of <FIG>, an inlet portion <NUM> is formed circumferentially on the lateral wall <NUM> to be adjacent to the common border <NUM>. As mentioned above, this inlet portion <NUM> extends from the common border <NUM> along the chamber axis X according to <NUM>/<NUM> of the length L2 of the lateral wall <NUM> according to this axis X.

As in the previous embodiment, the inlet portion <NUM> forms at least one inlet hole which is in fluid communication with one or several air inlets arranged in the housing <NUM> of the device <NUM>. Thus, one or several airflow paths are formed inside the housing <NUM> and extend then through the substrate portion <NUM> and the filter portion <NUM> of the consumable article <NUM> until the non-wrapped end of the filter portion <NUM>. These paths inside the substrate portion <NUM> are shown on <FIG>.

In the example of <FIG>, the inlet portion <NUM> comprises two triplets of inlet holes 62A, 62B. The triplets 62A, 62B can for example be arranged to face each other. In each triplet 62A, 62B, the inlet holes can be arranged homogenously according to the chamber X. Additionally, at least two inlet holes of different triplets 62A, 62B can be arranged according to the same transversal direction Y. According to another example, the inlet portion <NUM> can comprise for example only one inlet hole which can have a greater diameter than the inlet holes of the triplets 62A, 62B. According to still another example, the inlet portion <NUM> can define a plurality of inlet holes arranged according to one or several circumferential directions extending through the lateral wall <NUM>. Along the corresponding circumferential direction, the inlet holes can for example be arranged homogeneously. According to still another example, the inlet portion <NUM> can define a plurality of inlet holes arranged symmetrically in respect with a centre axis passing though the centre C of the bottom wall <NUM> parallel to the chamber axis X. According to still another example, one or several inlet holes can be arranged adjacent to the common border <NUM>. Of course, other examples of inlet holes arrangement and their number are still possible.

Additionally, in the example of <FIG>, the heating element <NUM> extends from the centre C of the bottom wall <NUM> and no inlet hole <NUM> is formed in this wall. However, in a general case, at least one inlet hole may be formed in the bottom wall <NUM>. For example, when the heating is performed by an element other than the heating blade <NUM>, an inlet hole may be formed at the centre C of the bottom wall <NUM>.

According to the third embodiment of the invention, the wrapper <NUM> of the consumable article <NUM> forms advantageously an opening facing each inlet hole. In this case, the wrapper <NUM> can comprise a label or any other key element indicating to the user the right insertion orientation of the consumable article <NUM> in the heating chamber <NUM>. According to another example, the wrapper <NUM> can be formed at least partially from an air permeable material.

<FIG> shows the heating chamber <NUM> according to the fourth embodiment of the invention. This embodiment corresponds to a combination of the previous two embodiments and in some cases, of all of the three previous embodiments.

Particularly, according to the fourth embodiment, an inlet portion is formed on the bottom wall <NUM> and an inlet portion is formed on at least one lateral wall <NUM> of the heating chamber <NUM>. Each of these inlet portions is similar to the respective inlet portion explained above. Thus, the inlet portion formed on the bottom wall <NUM> extends on this wall <NUM> according to each transversal direction Y perpendicular to the chamber axis X and passing through a centre C of the bottom wall <NUM>, from the common border <NUM> until <NUM>/<NUM> of the total length L1 of the bottom wall <NUM> according to this direction Y. Similarly, the inlet portion formed on at least one lateral wall <NUM> extends on this lateral wall <NUM>, according to the chamber axis X, from the common border <NUM> until <NUM>/<NUM> of the total length L2 of this lateral wall according to this axis X.

In the example of <FIG>, an inlet portion <NUM> is formed on the bottom wall <NUM> and an inlet portion <NUM> is formed one the lateral wall <NUM>.

Additionally, as in the previous cases, each inlet portion <NUM>, <NUM> comprises at least one inlet hole similar to the inlet holes explained above. For example, as shown on <FIG>, the inlet portion <NUM> of the bottom wall <NUM> can form two inlet holes arranged according the same transversal direction Y and the inlet portion <NUM> can form two triplets of inlet holes facing each other. These inlet holes form several airflow paths inside the substrate portion <NUM> as shown on <FIG>.

Claim 1:
An aerosol generating device (<NUM>) configured to operate with a consumable article (<NUM>) comprising a substrate portion (<NUM>) containing a solid substrate and defining an external surface;
the aerosol generating device (<NUM>) comprising a heating chamber (<NUM>) extending along a chamber axis (X) and configured to receive at least the substrate portion (<NUM>) of the consumable article (<NUM>);
the heating chamber (<NUM>) comprising a plurality of contact walls (<NUM>, <NUM>) designed to be in contact with the external surface of the substrate portion (<NUM>) of the consumable article (<NUM>),
the aerosol generating device (<NUM>) being characterized in that the plurality of contact walls (<NUM>, <NUM>) comprises a bottom wall (<NUM>) arranged substantially perpendicularly to the chamber axis (X) and at least one lateral wall (<NUM>) arranged substantially parallel to the chamber axis (X), the bottom wall (<NUM>) being in contact with the or each lateral wall (<NUM>) along a common border (<NUM>);
the heating chamber (<NUM>) further comprising a heating element (<NUM>) extending from a centre (C) of the bottom wall (<NUM>) parallel to the or at least one lateral wall (<NUM>);
the heating chamber (<NUM>) further comprising an inlet portion (<NUM>; <NUM>; <NUM>) comprising an inlet hole (52A, 52B; 62A, 62B) of an airflow path extending through the substrate portion (<NUM>) of the consumable article (<NUM>) when it is received in the heating chamber (<NUM>) and when the device (<NUM>) is operated to generate aerosol;
said inlet portion (<NUM>; <NUM>; <NUM>) extending on the bottom wall (<NUM>) and/or on the or at least one lateral wall (<NUM>) to create an airflow gradient at least at a region of the heating chamber (<NUM>) adjacent to this inlet portion, said airflow gradient extending from the centre (C) of the bottom wall (<NUM>) until the common border (<NUM>).