An inlet flange for an aftertreatment system component comprising: a flange body (300; 700) having a first end (310; 710) and a second end (320; 720), the first end (310; 710) comprising a flange inlet opening (312; 712) having a first diameter (d 1) and defining a longitudinal axis (350; 750), the second end (320; 720) comprising a flange outlet opening (322; 722) having a second diameter (d 2), the second diameter (d 2) being greater than the first diameter (d 1), wherein the second end (320; 720) is configured to be coupled to a body of an aftertreatment system component, and wherein the flange body (300; 700) defines an expansion chamber (332; 732) of the inlet flange; a first deflection member (210; 610) coupled to the flange body (300; 700) at a first end (216; 616) and a second end (218; 618) of the first deflection member (210; 610), wherein the first deflection member (210; 610) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a first direction relative to the longitudinal axis (350; 750); a second deflection member (220; 620) coupled to the flange body (300; 700) at a first end and a second end of the second deflection member (220; 620), wherein the second deflection member (220; 620) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a second direction relative to the longitudinal axis (350; 750), and wherein the second direction is a mirrored direction of the first direction along the longitudinal axis (350; 750); a third deflection member (230; 630) is positioned between the first deflection member (210; 610) and the second deflection member (220; 620) and is coupled to the first deflection member (210; 610) at a first end of the third deflection member (230; 630) and to the second deflection member (220; 620) at a second end of the third deflection member (230; 630), wherein the third deflection member (230; 630) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a third direction relative to the longitudinal axis (350; 750), and wherein the third direction is substantially perpendicular to a plane containing the first direction and the second direction; and a fourth deflection member (240; 640) is positioned between the first deflection member (210; 610) and the second deflection member (220; 620) and is coupled to the first deflection member (210; 610) at a first end of the fourth deflection member (240; 640) and the second deflection member (220; 620) at a second end of the fourth deflection member (240; 640), wherein the fourth deflection member (240; 640) is configured to deflect fluid flow outwardly away from the longitudinal axis (350; 750) in a fourth direction relative to the longitudinal axis (350; 750), and wherein the fourth direction is a mirrored direction of the third direction along the longitudinal axis (350; 750). a flange body (300; 700) having a first end (310; 710) and a second end (320; 720), the first end (310; 710) comprising a flange inlet opening (312; 712) having a first diameter (d 1) and defining a longitudinal axis (350; 750), the second end (320; 720) comprising a flange outlet opening (322; 722) having a second diameter (d 2), the second diameter (d 2) being greater than the first diameter (d 1), wherein the second end (320; 720) is configured to be coupled to a body of an aftertreatment system component, and wherein the flange body (300; 700) defines an expansion chamber (332; 732) of the inlet flange; a first deflection member (210; 610) coupled to the flange body (300; 700) at a first end (216; 616) and a second end (218; 618) of the first deflection member (210; 610), wherein the first deflection member (210; 610) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a first direction relative to the longitudinal axis (350; 750); a second deflection member (220; 620) coupled to the flange body (300; 700) at a first end and a second end of the second deflection member (220; 620), wherein the second deflection member (220; 620) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a second direction relative to the longitudinal axis (350; 750), and wherein the second direction is a mirrored direction of the first direction along the longitudinal axis (350; 750); a third deflection member (230; 630) is positioned between the first deflection member (210; 610) and the second deflection member (220; 620) and is coupled to the first deflection member (210; 610) at a first end of the third deflection member (230; 630) and to the second deflection member (220; 620) at a second end of the third deflection member (230; 630), wherein the third deflection member (230; 630) deflects fluid flow outwardly away from the longitudinal axis (350; 750) in a third direction relative to the longitudinal axis (350; 750), and wherein the third direction is substantially perpendicular to a plane containing the first direction and the second direction; and a fourth deflection member (240; 640) is positioned between the first deflection member (210; 610) and the second deflection member (220; 620) and is coupled to the first deflection member (210; 610) at a first end of the fourth deflection member (240; 640) and the second deflection member (220; 620) at a second end of the fourth deflection member (240; 640), wherein the fourth deflection member (240; 640) is configured to deflect fluid flow outwardly away from the longitudinal axis (350; 750) in a fourth direction relative to the longitudinal axis (350; 750), and wherein the fourth direction is a mirrored direction of the third direction along the longitudinal axis (350; 750).