时尚汽车_汽车生活移动版

Exemplary embodiments of the disclosure are described herein with reference to FIGS. 1-13 which are schematic illustrations of idealized embodiments and intermediate structures. As such, variations in the shapes and sizes of the structures illustrated in FIGS. 1-13 due to, for example, manufacturing techniques and/or tolerances, are contemplated. Thus, the structures described herein with reference to FIGS. 1-13 are not limited to the particular sizes and shapes of the illustrated structures, elements and features, but instead include deviations in the shapes and sizes that result, for example, from manufacturing techniques and/or tolerances. Thus, the structures, elements and features illustrated in FIGS. 1-13 are exemplary and schematical in nature, and their shapes and sizes do not necessarily illustrate the actual shapes and sizes of the structures, elements and features of the present invention, and are likewise not intended to limit the scope of the present invention.

Within a gas turbine engine, stationary shroud segments (also known as “blade track segments”) are typically assembled circumferentially about an axial flow engine axis and are positioned radially outward from rotating turbine blades. A clearance between the tips of the rotating turbine blades and the juxtaposed surface of the blade tracks (also known as “shroud clearance” or “blade clearance”) is often kept to a minimum distance so as to enhance the operating efficiency of the gas turbine engine.

Referring to FIG. 1, shown therein is a blade track 100 according to one embodiment of the present invention. The blade track 100 generally includes a segment portion 102 and attachment portions 104a and 104b (also generally referred to herein as attachment portion(s) 104″) extending from the segment portion 102 in a radially outward direction. In one embodiment, the attachment portions 104 can be formed separately from the segment portion 102 and subsequently coupled to the segment portion 102 by known methods and techniques. In another embodiment, and as will be described in greater detail below, the attachment portions 104 can be integrally formed with the segment portion 102 so as to define a unitary, monolithic structure. In a further embodiment, the segment portion 102 and the attachment portions 104 are provided as an integrally-formed unitary/monolithic ceramic matrix composite (CMC) structure.

The segment portion 102 generally includes a segment body 106 having a radially-facing inner surface 108, an opposite radially-facing outer surface 110, a first axially-facing surface 112, and a second axially-facing surface 114 opposite the first axially-facing surface 112. Generally, the radially-facing inner surface 108 is juxtaposed with respect to the tips of the rotary turbine blades, and is exposed to high pressures and temperatures of the gas flow path that drives the rotary turbine blades. Thus, the distance between the radially-facing inner surface 108 and the blade tips of the rotary turbine blades (not shown in the drawings) corresponds to the blade or shroud clearance. The radially-facing outer surface 110 generally faces toward the outer casing of the turbine engine and is exposed to pressures and temperatures that are typically significantly lower than those exerted onto the radially-facing inner surface 108.

The attachment portion 104a is structured and positioned such that a midpoint thereof is spaced apart from the second axially-facing surface 114 along the axial direction by a distance x1. Similarly, the attachment portion 104b is structured and positioned such that a midpoint thereof is spaced apart from the first axially-facing surface 112 along the axial direction by a distance x2. Distance x1 may be the same as or different from (i.e., greater than or less than) distance x2. In one embodiment; midpoints of the attachment portions 104a, 104b may be spaced apart from one another along the axial direction by a distance x3. Distance x3 may be the same as one or both of distances x1 and x2, or may be different from (i.e., greater than or less than) one or both of distances x1 and x2. In general the total distance (x1+x2±x3), is at least equal to the width of the tips of the corresponding turbine blades as defined by a chord length between the leading and trailing edges at the tip of the blade.

Each of the attachment portions 104a and 104b includes a transition region 116, an extension region 118, and a coupling region 120. The transition region 116 extends radially outward from the radially-facing outer surface 110 to the extension region 118 and forms a generally arcuate transition surface 122. The width w1 of the attachment portions 104a, 104b at the radially-facing outer surface 110 of the segment body 106 along the axial direction (i.e., the axial width of the transition region 116 at its widest point) may be less than one-half of the axial length of the segment body 106 (i.e., the distance separating the first and second axially-facing surfaces 112, 114). In any event, the width w1 will be designed such that the attachment portions 104 can withstand operational loads transmitted by the blade track. The extension region 118 extends radially outward from the transition region 116 to the coupling region 120, and may have a length selected to ensure an adequate blade clearance. However, in other embodiments, the extension region 118 may be omitted. In the illustrated embodiment, the coupling region 120 has a trapezoid-shaped (also referred to as a “dovetail”) cross section forming pairs of axially-opposite mating surfaces 124, and an attachment termination surface 126 extending between the opposite mating surfaces 124. The axially-opposite mating surfaces 124 generally diverge away from one another along a radially outward direction (i.e., toward the attachment termination surface 126), or generally converge toward one another along a radially inward direction (i.e., toward the radially-facing outer surface 110 of the segment body 106). As will be discussed in greater detail below, the axially-opposite mating surfaces 124 of the coupling region 120 can engage with corresponding mating surfaces of a hanger to thereby secure the blade track 100 within a blade track assembly of a gas turbine engine. In the illustrated embodiment, the coupling region 120 of the attachment portion 104 can carry high loads without developing undesirably high localized stresses.