This application relates to a combustion liner with cooling structure for a hula seal.
Gas turbine engines are known, and include a compressor section compressing air and delivering it downstream to a combustion section. The compressed air is mixed with fuel in the combustion section and burned. Products of the combustion pass downstream to a turbine section.
A combustion liner directs the products of combustion from the combustion section downstream to the turbine section. The combustion liner becomes quite hot during operation. As such, it is known to provide cooling air to cool the combustion liner.
A downstream end of the combustion liner typically fits into a transition duct which is connected to the turbine section. A hula seal attached to the combustion liner provides a slidable connection to the transition duct. Since there can be a good deal of relative expansion between the transition duct and the combustion liner, the two components are allowed to slide relative to each other. The hula seal provides a spring bias to hold the combustion liner in the transition duct, but still allow the sliding movement.
In the past, it is known to provide cooling air to a location between the hula seal and the combustion liner. A plurality of ridges are formed in an outer periphery of the combustion liner to provide cooling air paths. This design does not provide as efficient heat transfer as is desired.
A combustion duct assembly has a transition duct and a combustion liner. The combustion liner has a hula seal at a downstream end that is forced within an inner wall of the transition duct. The combustion liner is held within the transition duct by the hula seal, but allowed to move relative to the transition duct. The combustion liner is formed with heat transfer columns adjacent the downstream end, and radially inwardly of the hula seal. The combustion liner itself is also claimed.
The use of columns increases the heat transfer coefficient while providing a robust design that is relatively inexpensive to manufacture.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
The hula seal 50 is biased against the inner wall 55, and thus serves to hold the combustion liner 48 to the transition duct 52. However, the two can slide relative to each other when there is relative expansion due to the hot gasses that will flow within the combustion liner 48.
As shown in
As shown in
The columns 60 allow air to flow between the hula seal 50 and the combustion liner 48. Use of the columns 60 increases the flow cross-sectional area of the heat transfer surfaces, and further facilitates torturous air flow over a greater portion of the outer periphery of the combustion liner than if the simple ridges were utilized. The torturous flow path increases the heat transfer efficiency.
While the columns 60 are illustrated in one array in
Also, while the invention is illustrated as the complete duct assembly, the combustion liner 48 can also be retrofitted into existing duct assemblies 45.
Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.