A feedthrough assembly includes a main housing, a first inner housing positioned within the main housing and defining a plurality of first inner conduits, a second inner housing positioned within the main housing and defining a plurality of second inner conduits, and a chamber defined by an internal surface of the main housing, a first end of the first inner housing, and a first end of the second inner housing that faces the first end of the first inner housing. Each of the plurality of first inner conduits is aligned with a corresponding one of the plurality of second inner conduits. A cross-sectional area of the chamber varies along a longitudinal axis of the main housing.