Cooling Air Flow Characteristics in Gas Turbine Components

Abstract

An analytical model for the prediction of cooling air flow characteristics (mass flow rate and internal pressure distribution) in gas turbine components is discussed. The model addresses a number of basic flow elements typical to gas turbine components such as orifices, frictional passages, labyrinth seals, etc. Static bench test measurements of the flow characteristics were in good agreement with the analysis. For the turbine blade, the concept of equivalent pressure ratio is introduced and shown to be useful for predicting (1) the cooling air flow rate through the rotor blade at engine conditions from the static rig and (2) cooling air leakage rate at the rotor serration at engine conditions. This method shows excellent agreement with a detailed analytical model at various rotor speeds. A flow calibration procedure preserving flow similarity for blades and rotor assemblies is recommended.

A Computer Model for Gas Turbine Blade Cooling Analysis

“…In the development of this program, the original technique was one in which the variable to be determined was the estimated inlet pressure. In a similar iteration, Jen and Sobanik [7] also used the inlet pressure as the variable to be determined. This technique, which has been run successfully as a subroutine of this program has two major drawbacks.…”

“…A program had been derived by NASA which could calculate the surface temperature of a full-coverage film cooled vane/blade coated with a thermal barrier [6], but the program was not developed for the blades with multipass coolant ducts configuration. An analytical model for the prediction of cooling air flow rate and pressure distribution in gas turbine components was developed by AVCO Lycoming [7], but the model did not include the prediction of the local metal temperature of the blades. The major turbine manufacturers may have their own computer models, but they are not available to the public.…”

Coupled flow network model and CFD analysis for a combined impingement and film cooled gas turbine nozzle guide vane

“…In the preliminary design stage of a cooled gas turbine nozzle guide vane (NGV), twodimensional numerical methods are not very appropriate. On the other hand, both threedimensional analyses of NGV cooling passages and the experimental techniques are very timeconsuming, as their geometries are too complex with multiple rows of (inline/ Jen and Sobanik et al [2] developed an analytical model for the prediction of cooling air flow characteristics such as mass flow rate and internal pressure distribution in the gas turbine components. They addressed a number of basic flow elements such as orifices, frictional passages, seals etc.…”