Flow Characteristics of the Nozzle Blade Cascade in the Mode of the Joint Operation with the Radial Diffuser

The obtained research data are given for the nozzle cascade used by a small-size gas turbine of an average fanning in combination with the radial diffuser. Aerodynamic characteristics of the nozzle blade cascade were determined in a wide range of a change in the Reynolds number varying from 4∙105 to 106 and the reduced velocity varying in the range of 0.4 to 1.13. The flow rate coefficient of the nozzle cascade was derived for all modes using the integral methods and the drainages behind the cascade. The kinetic energy loss coefficient and the flow angles were calculated using the measurement data of flow parameters in three control modes that were obtained due to the use of orientable pneumometric probes. When the expansion degree of the convergent –divergent annular duct behind the cascade is equal to 1.43 the flow in the narrow section of this duct is “enlocked” in the mode when the reduced velocity behind the cascade is equal to 1.127. At such velocity the Reynolds number 106 is self-similar for the flow rate coefficient. At lower values of Reynolds number, the decrease of it is accompanied by an intensive decrease in the flow rate coefficient for all the values of the reduced velocity. For the Reynolds number lower than 7∙105 an increase in the velocity results in a decreased flow rate coefficient. When this number exceeds 8∙105 an increase in the velocity results in an increase of the flow coefficient up to the moment when the flow is “enlocked” in the nozzle cascade.

OBTAINING OF EXPERIMENTAL CONSTRUCTIONALLY SIMILAR SAMPLE OF THE NOZZLE ASSEMBLY SECTOR AND CARRYING OUT ITS TESTS AT TEMPERATURE OF 1500 °С

The interaction of the SiC–SiCw–B4C–AlN system ceramic composite material (CCM) with the EP648 alloy in the process of high-temperature brazing was studied. The smallest erosion activity both in relation to CCM, and to the EP648 alloy, has HMP solder VPr50. An experimental constructionally similar sample of the nozzle assembly sector was made using uncooled nozzle blade prototypes from CCM. Tests of an experimental constructionally similar sample of the nozzle assembly sector at a temperature of 1500 °C were carried out. No traces of material ablation from the surface of the CMC were found.

Detailed Design and Aerodynamic Performance Analysis of a Radial-Inflow Turbine

Radial-inflow turbines (RI turbines) are critical components of air cycle machines (ACM), utilized in environment conditioning systems (ECS). In this work, a process is presented for the full design of a radial-inflow turbine, including volute, nozzle blade row and rotor blade row. The preliminary and detailed aerodynamic design approaches are explained in detail. A mean-line (1D) analysis method coupled with the preliminary design is employed to evaluate the aerodynamic performance of the RI turbine. Then, ANSYS CFX is used to perform unsteady 3D simulations of the designed RI turbine at design and off-design conditions to predict the aerodynamic performance of the turbine for future optimization.