Air cycle machines and methods of communicating fluid through air cycle machines

A method of communicating fluid within an air cycle machine, comprising:

• at an air cycle machine including a housing with an exterior wall defining therethrough an overboard air inlet, an ambient air inlet, and an ambient air outlet;
• a scavenging turbine arranged within the housing and supported for rotation about a rotation axis and in fluid communication with the overboard air inlet;
• and an ambient air fan arranged within the housing and supported for rotation about the rotation axis within the housing, the ambient air fan having a radially inner spoked portion a and radially outer bladed portion, the radially outer bladed portion fluidly coupling the ambient air inlet to the ambient air outlet, the radially inner spoked portion fluidly coupling the scavenging turbine to the ambient air fan within the housing;
• receiving an overboard air flow at the overboard air inlet;
• receiving an ambient air flow at the ambient air inlet;
• extracting work from the overboard air flow with the scavenging turbine;
• rotating the ambient air fan with the work extracted by the scavenging turbine;
• driving the ambient air flow received at the ambient air inlet to the ambient air outlet with the radially outer bladed portion of the ambient air fan;
• and
• communicating the overboard air flow to the ambient air outlet through the radially inner spoked portion of the ambient air fan.