Radial turbines

Claim 1

A radial turbine having a turbine blade, the angle of rake of which, relative to a turbine exit surface, perpendicular to the axis of the turbine, at a radius R 2 from the axis of the turbine at the exit portion, and β 2 and is obtained by the following formula: β.sub.2 =tan.sup.-1 (W.sub.2 a/W.sub.2 u), wherein W.sub.2 u=U.sub.2 -C.sub.2 u and i W.sub.2 a=√W.sub.2.sup.2 -W.sub.2 a.sup.2, in which, W 2 u and W 2 a are peripheral and axial components respectively of W 2 , which is the velocity of combustion gas relative to the turbine rotor at the circular surface including said radius R 2 at a designated rotor velocity, and, ##EQU2## in which, ##EQU3## A, B and C are coefficients, R 1 =the distance of a turbine entrance portion from the axis of the turbine; R 2 =the distance between the axis of the turbine and an intersecting point of the turbine exit surface and a cross-section of the turbine blade along a designated line of flow of the combustion gas flowing through a space between two adjacent turbine blades; W 1 =the relative velocity between the combustion gas and the turbine rotor at the turbine entrance portion and at the designated rotor velocity; U 1 =the peripheral velocity of the turbine rotor at the turbine entrance portion and at the designated rotor velocity; U 2 =the peripheral velocity of the turbine rotor at the radius R 2 on the turbine exit surface and at the designated rotor velocity; g=gravitational acceleration; J=heat equivalent of work; C p =specific heat at constant pressure of the combustion gas; P 1 =the pressure of the combustion gas at the turbine entrance portion and at the designated rotor velocity; T 1 =the absolute temperature of the combustion gas at the turbine entrance portion and at the designated rotor velocity; P 2 =the pressure of the combustion gas at the circular surface including said radius R 2 on the turbine exit surface and at the designated rotor velocity; γ=the ratio of the specific heat at constant pressure of the combination gas to the specific heat at constant volume of the combustion gas.