Description:The methodology introduced, comprises of the following features:
In the present invention of the gas generator turbine engine, a deep groove ball bearing (111) and a cylindrical roller bearing (112) in tandem configuration (110) has been introduced to overcome the problems faced in the existing design with two angular contact bearings preloaded with a spring.
A flexible bearing support system is incorporated to the rotor system (100) by using a bearing housing (200) with flexible ribs (230) for an improved engine rotor dynamics without any external damping.
Bearings (111 & 112) are lubricated for smooth operation and limiting bearing temperatures within acceptable limit. To avoid leakage of lubricating oil into gas flow path, the gas generator core is provided with hybrid combinations of air-oil seals in the bearing chambers (180 & 190).
, C , Claims:1. Arrangement of bearings of a gas generator turbine engine to support axial thrust and radial load at different operating speeds and temperature profiles, and to operate the gas generator rotor system (100) with a stable rotor dynamic behavior throughout its operating envelope along with a hybrid air-oil sealing arrangement to arrest leakage of lubrication oil of the said bearings, comprising:
a tandem bearing configuration (110) to support the rotor system (100);
a bearing housing (200) to house the bearings (111 & 112); and
a bearing support (300) to ground the bearings (111 & 112) to engine casing (600).
2. The said arrangement of bearings as claimed in Claim 1, wherein said tandem bearing configuration (110), characterized by:
a deep groove ball bearing (111) to the front of the said rotor system (100) to support complete axial thrust and partial radial load;
a cylindrical roller bearing (112) to the rear of the said rotor system (100) to support radial load and allow thermal growth of the said rotor system (100); and
a spacer (113) to maintain distance between the said bearings (111 & 112).
3. The said hybrid air-oil sealing arrangement as claimed in Claim 1, comprising:
a piston seal arrangement (150) upstream to said deep groove ball bearing (111);
a labyrinth seal arrangement (811) upstream to the said piston seal arrangement (150) of said deep groove ball bearing (111);
a piston seal arrangement (160) downstream to said cylindrical roller bearing (112);
a labyrinth seal arrangement (812) downstream to the said piston seal arrangement (160) of said cylindrical roller bearing (112); and
static compressible rubber seal arrangements (821, 822 & 823) between static interfaces.
4. Each of the said piston seal arrangements (150 & 160) upstream to said deep groove ball bearing (111) and downstream to said cylindrical roller bearing (112) as claimed in Claim 3, characterized by:
a floating piston ring (151 & 161);
a rotating seal carrier (152 & 162) to house each of the said piston rings (151 & 161); and
a static housing (510 & 430) around each of the said piston rings (151 & 161) to rub against to provide contact type dynamic sealing.
5. The said labyrinth seal arrangement (811) upstream to the said piston seal arrangement (150) of said deep groove ball bearing (111) as claimed in Claim 3, characterized by:
a set of labyrinth teeth (121) integrally machined on centrifugal impeller (120); and
a static housing (310) integral to the said bearing support (300) as claimed in Claim 1 with abradable coating (320) around the said set of labyrinth teeth (121) to provide non-contact type dynamic sealing.
6. The said labyrinth seal arrangement (812) downstream to the said piston seal arrangement (160) of said cylindrical roller bearing (112) as claimed in Claim 3, characterized by:
a set of labyrinth teeth (171) machined on a rotating disc (170) mounted on turbine (130); and
a static housing (410) with abradable coating (420) around the said set of labyrinth teeth (171) to provide non-contact type dynamic sealing.
7. The said bearing housing (200) as claimed in Claim 1, characterized by:
a set of circumferentially placed flexible ribs (230) to provide flexible support to the said bearings (111 & 112) without any external damping;
ground diameters (210 & 220) to house the said bearings (111 & 112);
a circumferential groove (240) to house retaining ring (700) that retains the outer race of said cylindrical roller bearing (112) in place;
a circumferential groove (250) to house the said static compressible rubber seal (822) to provide static sealing between the said bearing housing (200) and said bearing support (300);
two slots (260) for easy removal of said both bearings (111 &112);
two holes (270) for thermocouple insertion to measure temperature of said both bearings (111 & 112) during engine operation; and
two slots (280) to drain bearing lubrication oil from said bearing chambers (180 & 190).
8. The said bearing support (300) as claimed in Claim 1, characterized by:
a ground diameter (330) forming said housing (310) to said labyrinth seal arrangement (811) as claimed in Claim 5;
a circumferential groove (340) to house the said static compressible rubber seal (823) to provide static sealing between the said bearing support (300) and the integrated seal housing (400) to the said piston seal & said labyrinth seal arrangements (160 & 812) downstream to said cylindrical roller bearing (112);
a provision (350) for oil inlet to the said bearings (111 & 112) for lubrication;
a provision (360) for oil sump to retain oil before drain and to avoid leakages through seals after the engine is shut down;
a provision (370) for oil drain from the said oil sump (360); and
a provision (380) for air vent to maintain chamber pressure for the said bearings (111 & 112).
9. The said static housing (510) to the said piston seal arrangement (150) upstream to said deep groove ball bearing (111) as claimed in Claim 4, integrated to seal housing (500), characterized by:
a face groove (520) to house the said static compressible rubber seal (821) to provide static sealing between the said bearing housing (200) and said seal housing (500).