An air channel assembly, comprising: a casing provided with an air supply channel and a drainage port therein, the air supply channel having an air inlet and a bottom air supply port, an air-supply guide portion configured to lead air to the bottom air supply port and a drainage guide portion configured to lead water to the drainage port being provided adjacent to the bottom air supply port, a guide direction of the air-supply guide portion being away from a guide direction of the drainage guide portion; wherein the air-supply guide portion comprises: a first air-supply guide section connected with the air supply channel; and a second air-supply guide section spaced apart from the first air-supply guide section and being consistent with the first air-supply guide section in guide directions, the drainage guide portion being located between the first air-supply guide section and the second air-supply guide section and the guide direction of the drainage guide portion being away from the guide direction of the first air-supply guide section; wherein the drainage guide portion comprises: a first drainage guide section connected with the first air-supply guide section; characterized in that: a second drainage guide section connected with the second air-supply guide section and located below the first drainage guide section; the drainage port is defined in the first drainage guide section, and the bottom air supply port is defined above the second air-supply guide section and opposite to the second air-supply guide section. a casing provided with an air supply channel and a drainage port therein, the air supply channel having an air inlet and a bottom air supply port, an air-supply guide portion configured to lead air to the bottom air supply port and a drainage guide portion configured to lead water to the drainage port being provided adjacent to the bottom air supply port, a guide direction of the air-supply guide portion being away from a guide direction of the drainage guide portion; wherein the air-supply guide portion comprises: a first air-supply guide section connected with the air supply channel; and a second air-supply guide section spaced apart from the first air-supply guide section and being consistent with the first air-supply guide section in guide directions, the drainage guide portion being located between the first air-supply guide section and the second air-supply guide section and the guide direction of the drainage guide portion being away from the guide direction of the first air-supply guide section; a first air-supply guide section connected with the air supply channel; and a second air-supply guide section spaced apart from the first air-supply guide section and being consistent with the first air-supply guide section in guide directions, the drainage guide portion being located between the first air-supply guide section and the second air-supply guide section and the guide direction of the drainage guide portion being away from the guide direction of the first air-supply guide section; wherein the drainage guide portion comprises: a first drainage guide section connected with the first air-supply guide section; characterized in that: a second drainage guide section connected with the second air-supply guide section and located below the first drainage guide section; the drainage port is defined in the first drainage guide section, and the bottom air supply port is defined above the second air-supply guide section and opposite to the second air-supply guide section. a first drainage guide section connected with the first air-supply guide section; characterized in that: a second drainage guide section connected with the second air-supply guide section and located below the first drainage guide section; the drainage port is defined in the first drainage guide section, and the bottom air supply port is defined above the second air-supply guide section and opposite to the second air-supply guide section. a second drainage guide section connected with the second air-supply guide section and located below the first drainage guide section; the drainage port is defined in the first drainage guide section, and the bottom air supply port is defined above the second air-supply guide section and opposite to the second air-supply guide section.