SU1296744A1 - Method for converting heat energy to mechanical energy - Google Patents

Abstract

Invention m. B. used for heat recovery in ship installations. The invention makes it possible to increase the power of the strength member and the allowable number of working cycles by increasing the creep resistance of the alloy. The cooled element (E) 1 is deformed by applying to it an external force PI in the counterclockwise direction to the position corresponding to its bend through the angle Φ1. In this case, the deformation (D) is evenly distributed along the length E 1, which is ensured by the forced limitation of D bending on the mandrel 4. Then the E 1 is heated to temperature exceeding the temperature of the end of the reverse martensitic transformation of its alloy. In the process of heating, the effect of the thermomechanical memory of the shape of the alloy appears. A 1 tends to maintain its original position and moves the load in the opposite direction to the original, developing a force P2 P | - At the same time, the stresses and stresses arising in material E 1 exceed the stresses and stresses that arise during its initial D in a cooled state. This provides useful mechanical work. After the restoration of the shape, E 1 occupies the position corresponding to its bend through the angle Φ2. After removal of the load, Э 1 moves to the position corresponding to its bend at the angle fz. Then E 1 is cooled again and the accumulated irreversible deformation E I, characterized by the angle f ,, is eliminated, made it D by the force of the RE in the opposite direction - clockwise to the position corresponding to its bend at an angle φ 4, with uniform distribution D I due to its bending on the mandrel 5. Next, E 1 is reheated again and it moves the load to the position corresponding to the angle φ5, its bend, developing the force P4- After removing the load, E 1 is moved to the position corresponding to its bend through the angle fe . The cycle described below is repeated with alternating deformation of Э 1 in opposite directions by the same value. 1 hp f-ly, 2 ill. (S ate with O5 vj 4; ia NU

Description

The invention relates to methods for converting thermal energy into mechanical energy due to thermal deformations of solid force elements from an alloy with the effect of a thermomechanical shape memory, and can be used primarily for heat recovery, for example, in ship installations.

The aim of the invention is to increase the power of the strength member and the allowable number of operating cycles by increasing the creep resistance of the alloy.

Fig. 1 shows a diagram of a device for deforming a power element on mandrels in different phases of implementation.

for each specific material based on operating conditions.

Element 1 is then heated to a temperature above the temperature Ax of the end of the reverse martensitic transformation of its alloy. In the process of heating, the effect of the thermomechanical memory of the shape of the alloy of which element 1 is made appears. Heated element 1 tends to return to its original position and moves the load (not

 It is shown that the load is connected to the coupling 3) in the opposite direction of the initial deformation of the element 1, developing a force Pr PI. At the same time, the stresses and stresses arising in the material of the power auxiliary cycle; Fig. 2 shows the graphics of 1, is superior to stresses and stresses.

the characteristics of the irreversible accumulated deformation — the angle of bending of the force element — from the number of cycles n: curves a and b — for deforming the force element on the mandrels with alternating changes in the direction of bending, respectively, for each direction of bending; curve c is for deforming the element on the mandrel in one direction; curve r - for deforming an element without a mandrel in one direction.

A device for carrying out the method (Fig. 1) contains a thermosensitive power element 1 made of an alloy with the effect of a thermomechanical shape memory. At one end, the force element 1 is secured during its initial deformation in a cooled state, which ensures useful mechanical work.

25

20 After the restoration of the shape, the element 1, connected to the load, takes the position corresponding to its bending at an angle Φ2. After removal of the load due to the elastic properties of the material, force element 1 moves to the position corresponding to its bending at an angle of fz. Then element 1 is again cooled to a temperature below Mn, and the accumulated irreversible deformation of element 1, characterized by an angle of fz, is eliminated by deforming it is external on base 2, and on the other end of it Q with a force P in the opposite direction, a rigid cylindrical coupling 3 ta-nii (clockwise) is worn to the position

CIM in such a way that immobility is ensured by the angle corresponding to its bending at an angle f4 from the connection of element 1 and clutch 3. By an evenly distributed strain distribution

sides of the power element 1 on the basis of the length of the element 1 due to its bending

2 is mounted without a gap cylindrical on the mandrel 5 of constant curvature. Further

The mandrels 4 and 5, having in cross-section 35, element 1 is again heated to a temperature higher than the gas station, and as a result of the effect of the thermomechanical memory, the heated element 1 moves the load to the position corresponding to the angle fz, its bending, developing a force P4. After cn - 40 gi of load, element 1 moves to the position corresponding to its bend at an angle fb. Further, the proposed cycle is repeated with alternating deformation of element 1 in mutually opposite directions on., The same value.

The results of measuring the bending angles Фз and Фб, characterizing the accumulated irreversible deformation of the element 1, are shown in Fig. 2 (see curves, respectively, o and b). These dependences are obtained for the following experimental conditions: the diameter of the power element 1 is 4 mm; the temperatures of the beginning and end of the forward and reverse martensitic transformations of the alloy of element 1, respectively, are: Mn 20 ° C, Mk 0 ° C, AH 25 ° C, Ac 50 ° C; radius R of the forced limitation of the deformation of 55 mandrels 4 and 5 is 0.025 m; the distance 1 from the bend on the mandrel 4 of the constant curvature of the junction of the element 1 and the coupling 3 to

us The optimum amount of deformation of the point of application of external deforming

element - 1 is determined experimentally by force Pj and P3 and load forces PZ and P4

passing through the plane of deformation of element 1, the shape of quadrants. The installation location of the coupling 3 on the element 1 is chosen so that in the maximum deformed condition of the element 1, the end face of the coupling 3 abuts against the edges of the mandrels 4 and 5. In the initial unloaded condition, the power element 1 with coupling 3 is perpendicular to the surface of the base 2.

The proposed method for converting thermal energy into mechanical energy is implemented as follows.

In the initial state, element 1 is cooled below the temperature Mn of the beginning of the direct martensitic transformation of its alloy. The cooled element 1 is deformed by applying an external force PI (moment) to it, in a counterclockwise direction to a position corresponding to its bend at an angle Y (Fig. 1). In this case, the deformation is evenly distributed along the length of the element 1, which is ensured by

for each specific material based on operating conditions.

Element 1 is then heated to a temperature above the temperature Ax of the end of the reverse martensitic transformation of its alloy. In the process of heating, the effect of the thermomechanical memory of the shape of the alloy of which element 1 is made appears. Heated element 1 tends to return to its original position and moves the load (not

 It is shown that the load is connected to the coupling 3) in the opposite direction of the initial deformation of the element 1, developing a force Pr PI. In this case, the stresses and stresses arising in the material of the power element, ment 1, are superior to stresses and stresses.

arising from its initial deformation in a cooled state, and this provides useful mechanical work.

equals 0.045 m; the temperature of the cooling element 1 running water is + 90 ° C. For comparison, Fig. 2 shows graphs of the accumulated irreversible bending angle φ of element 1 versus the number of cycles for deforming it on the mandrel 4 in one direction (curve c) and for deforming element 1 without the mandrel 4 in one direction (curve g).

As can be seen from these graphs, the deformation of the thermosensitive power element 1 without limiting the magnitude of the deformation and without changing its direction (curve r) causes its greatest creep, and the increment of irreversible accumulated deformation for the next two consecutive cycles is not zero. Deforming element 1 in the same direction with limiting the amount of deformation on the mandrel 4 by analogy with the prototype also leads to an increase in thermal cycling creep (curve C), and the increment of irreversible accumulated deformation for two consecutive cycles is also not zero. Deforming element 1 in accordance with the proposed method alternately in opposite directions by the same value with the forced limitation of the amount of deformation on mandrels 4 and 5 (curves a and b) ensures that after 10-15 cycles the stable values of angles sr and fe irreversible accumulated strain, the equality of the angles fz and fe and the absence of increment of these angles in the subsequent cycles of the deformation of the element 1. This in turn provides an increase in the power of the force element 1 due to the decrease in sweat pb energy associated with umenscheniem useful for strains used thermal power element 1, the Enhance stability transmitted load forces and displacements The amount and increase in the allowable 0-operation cycles.

Claims (2)

1. A method for converting thermal energy to mechanical energy by deformation in  the cooled state of a temperature-sensitive power element made of an alloy with a shape memory effect, with a uniform distribution of deformation along the length of the element, its subsequent heating and displacement by the heated element 0 load in the opposite direction of the original deformation, characterized in that, in order to increase the power of the strength element and the permissible number of operating cycles by increasing the creep resistance of the alloy, the deformation of the element is carried out alternately in mutually opposite directions. 2. A method according to claim 1, characterized in that the deformation of the element in mutually opposite directions is carried out by the same amount. five ha