Wash arm assembly and dishwasher comprising wash arm assembly

A wash arm assembly for a dishwasher, comprising:

• a wash arm comprising a circular opening with a centre and with an edge;
• and
• a mounting unit comprising a circular insertion portion and a supporting portion extending radially from said circular insertion portion,
• wherein said mounting unit is arranged to be inserted at least partly in said circular opening to mount said wash arm within said dishwasher and to allow rotation of said wash arm around a rotational axis of said wash arm,
• wherein said circular insertion portion is arranged to be inserted at least partly in said circular opening to form a passage between said edge and said circular insertion portion when said mounting unit is inserted at least partly in said circular opening, and
• wherein said supporting portion is arranged to support said wash arm when said circular insertion portion is inserted at least partly in said circular opening,
• wherein said wash arm comprises a protrusion), protruding parallely to said rotational axis towards said supporting portion when supporting said wash arm and extending around said centre, and
• wherein said supporting portion and said wash arm are arranged to form a chamber delimited by said passage and said protrusion when said supporting portion supports said wash arm.