JP4962501B2 - External combustion engine - Google Patents

Description

  The present invention relates to an external combustion engine that converts a displacement of a liquid portion of a working medium caused by a change in the volume of vapor of the working medium into mechanical energy and outputs the mechanical energy.

  Conventionally, this type of external combustion engine is described in Patent Documents 1 and 2. In the prior arts of Patent Documents 1 and 2, the working medium is sealed in a tubular container in a liquid state, and a part of the liquid working medium is heated and vaporized by the heating unit of the container, and the vaporized operation is performed. The liquid in the liquid state is displaced as a liquid piston by the volume variation of the vapor in the working medium by cooling the medium vapor in the cooling section of the container, and the displacement of the liquid piston is converted into mechanical energy for output. To do.

  Furthermore, in the prior art of Patent Document 2, the tubular container is expanded in a disk shape in the heating section. For this reason, when the vapor | steam of a working medium is cooled and liquefied in a cooling part, the working medium in a liquid state will flow in into the center part of a heating part, and will spread and flow toward the outer peripheral part of a heating part after that. Then, the working medium in the liquid state is heated in the heating unit and vaporizes again.

  According to the prior art of Patent Document 2, when the liquid working medium flows into the heating unit, the liquid working medium collides with the inner wall surface of the heating unit, so that the liquid working medium is agitated. As a result, turbulent flow occurs and the temperature boundary layer near the inner wall surface of the heating unit is destroyed. As a result, the heat exchange efficiency in the heating part can be improved.

JP 2004-84523 A Japanese Patent Laid-Open No. 2007-247592

  As described above, in the conventional techniques of Patent Documents 1 and 2, since the output is taken out when the working medium is vaporized in the heating unit, the working medium is moved to the cooling unit side without vaporizing in the heating unit. In this case, the working medium only transports the amount of heat given from the heating unit to the cooling unit, and the amount of heat given from the heating unit to the working medium does not contribute to the output, resulting in heat loss. Hereinafter, such heat loss is referred to as heat transport loss.

  According to the detailed examination of the present inventors, it has been found that the conventional techniques of Patent Documents 1 and 2 have a factor that increases heat transport loss. This will be described below.

  FIG. 6A shows an outline of the vicinity of the heating unit 11a in an external combustion engine (hereinafter referred to as an examination example) examined by the present inventor. It is equivalent.

  FIG. 6B is a graph showing the thickness distribution of the liquid film of the working medium 12 remaining on the inner surface of the heating unit 11a in the process of expanding the steam in the study example, and the liquid film thickness in the heating unit radial direction. The height distribution is shown corresponding to FIG.

  FIG. 6C is a graph showing the temperature distribution of the heating part 11a in the examination example, and shows the heating part temperature distribution in the heating part radial direction corresponding to FIG. 6A.

  Fig.7 (a) is the Z section enlarged view of Fig.6 (a). In FIG. 7 (a), broken line hatching schematically shows a liquid film of the working medium 12 remaining on the inner surface of the heating unit 11a.

  FIG.7 (b) is a graph which shows the liquid film thickness distribution in the Z section of Fig.6 (a), Comprising: The liquid film thickness distribution in a heating part radial direction is shown corresponding to FIG.7 (a). Yes. That is, FIG. 7B corresponds to an enlarged part of the graph of FIG.

  FIG.7 (c) is a graph which shows the moving speed (flow velocity) of the liquid piston in Z part of Fig.6 (a), Comprising: The change of the liquid piston moving speed in a heating part radial direction respond | corresponds to Fig.7 (a). As shown.

  FIG. 8 is a graph showing the position of the liquid piston liquid surface 12a (see FIGS. 6A and 7A) in the heating section 11a of the examination example, and the position of the liquid surface position in the heating section radial direction. The time change is shown.

  In the examination example, as can be seen from FIG. 8, the liquid surface position of the liquid piston changes with time in a sinusoidal shape. Therefore, the contact time with the liquid piston is shortened in the radially outer portion of the heating portion 11a, and the contact time with the liquid piston is lengthened in the radially inner portion of the heating portion 11a.

  In other words, the heat exchange time with the liquid piston is shortened in the radially outer portion of the heating portion 11a, and the heat exchange time with the liquid piston is lengthened in the radially inner portion of the heating portion 11a. For this reason, as shown in FIG. 6C, the temperature of the heating unit 11a decreases from the radially outer side toward the radially inner side.

  On the other hand, in the examination example, since the internal space of the heating part 11a is expanded in a disk shape, the liquid piston moving speed becomes slower as it goes from the radially inner side to the radially outer side of the heating part 11a as shown in FIG. .

  Therefore, as shown in FIGS. 6B, 7A, and 7B, the thickness of the liquid film of the working medium 12 remaining on the inner surface of the heating unit 11a becomes thinner from the radially inner side toward the radially outer side. . This phenomenon can be understood from the following formulas 1 and 2 and FIG.

但し、数式１においてδ（ｘ）は液膜厚さ、ｄは流路径または流路幅であり、数式２においてμは粘性係数、Uは流速、σは表面張力である。図９は、上記数式１、２において、流路径ｄを一定としたときの流速と液膜厚さとの関係を示すグラフである。

In Equation 1, δ (x) is the liquid film thickness, d is the channel diameter or channel width, and in Equation 2, μ is the viscosity coefficient, U is the flow velocity, and σ is the surface tension. FIG. 9 is a graph showing the relationship between the flow velocity and the liquid film thickness when the flow path diameter d is constant in the above formulas 1 and 2.

  In addition, the above formulas 1 and 2 are written by “Geoffrey Ingram Taylor”, “A Deposition of a Viscous Fluidon the Wall of a Tube”, Journal of Fluid Mechanics (Journal Of Fluids). (USA), Vol. 10, 1961, p. 161-165.

  Here, the liquid film remaining on the inner surface of the heating unit 11a boiled under reduced pressure due to a pressure drop when the steam expands and contributes to the output. Therefore, heat transport loss can be reduced if the liquid film remaining on the inner surface of the heating unit 11a can be efficiently boiled under reduced pressure.

  However, in this examination example, as can be seen from FIGS. 6B and 6C, the thickness of the liquid film remaining on the inner surface of the heating part 11a becomes thicker at the radially inner portion where the heating part temperature is lower, Since the thickness of the liquid film remaining on the inner surface of the heating part 11a becomes thinner as the outer portion in the radial direction becomes higher, the heating part temperature distribution and the liquid film thickness distribution are in conflict, so the inner surface of the heating part 11a The remaining liquid film cannot be efficiently boiled under reduced pressure. As a result, the heat transport loss is increased in the study example.

  For these reasons, the heat transfer loss increases in the prior art of Patent Document 2 described above. Moreover, also in the prior art of the said patent document 1, heat transport loss will increase for the same reason.

  In short, in the prior arts of Patent Documents 1 and 2 above, the portion of the heating unit having a lower temperature, that is, the portion on the cooling unit side, has a thicker liquid film remaining on the inner surface of the heating unit, and the temperature of the heating unit is higher. Since the thickness of the liquid film remaining on the inner surface of the heating part becomes thinner at the part, that is, the part opposite to the cooling part, the heating part temperature distribution and the liquid film thickness distribution are in conflict with each other. The transportation loss will increase.

  In view of the above points, an object of the present invention is to reduce heat transport loss by efficiently boiling a liquid film remaining on the inner surface of a heating unit under reduced pressure.

In order to achieve the above object, in the invention described in claim 1, a tubular container (11) in which a working medium (12) is encapsulated so as to be flowable in a liquid state;
A heating part (11a) that is formed at one end of the container (11) and heats and vaporizes a part of the liquid working medium (12);
A cooling unit (11b) that is formed at the other end side of the heating unit (11a) in the container (11) and that cools and liquefies the vapor of the working medium (12) vaporized by the heating unit (11a);
An output unit (15) that communicates with the other end of the container (11), converts the displacement of the liquid working medium (12) caused by the volume variation of the vapor into mechanical energy, and outputs the mechanical energy;
The heating unit (11a) has a liquid film thickness adjustment structure that adjusts the thickness of the liquid film remaining after the working medium (12) is vaporized.
The liquid film thickness adjusting structure is characterized in that the thickness of the liquid film is adjusted so as to increase the thickness of the liquid film in a portion of the heating section (11a) opposite to the cooling section (11b).

  According to this, since the thickness of the liquid film in the part opposite to the cooling part (11b) in the heating part (11a) can be increased, the liquid in the part having a high heating part temperature in the heating part (11a). The film thickness can be increased.

  For this reason, the heating part temperature distribution and the liquid film thickness distribution can be brought close to each other, and the liquid film remaining on the inner surface of the heating part (11b) can be efficiently boiled under reduced pressure. As a result, heat transport loss can be reduced.

  According to a second aspect of the present invention, in the external combustion engine according to the first aspect, the liquid film thickness adjusting structure is configured such that the thickness of the liquid film in a portion of the heating unit (11a) opposite to the cooling unit (11b). Liquid film at a portion of the heating section (11a) opposite to the cooling section (11b) so that the thickness of the liquid film at the section of the heating section (11a) on the cooling section (11b) side is uniform. The thickness is increased.

  In the invention according to claim 3, in the external combustion engine according to claim 2, as the cross-sectional area of the internal space of the heating part (11a) goes from the cooling part (11b) side to the opposite side to the cooling part (11b). The liquid film thickness adjusting structure is formed by forming the heating part (11a) so as to decrease.

  According to this, since the flow rate of the liquid working medium (12) in the part on the opposite side to the cooling part (11b) in the heating part (11a) can be increased, the cooling part ( It is possible to effectively increase the thickness of the liquid film at the site opposite to 11b) (see FIG. 9 above).

  According to a fourth aspect of the present invention, in the external combustion engine according to the first aspect, the liquid film thickness adjusting structure is configured such that the thickness of the liquid film in a portion of the heating section (11a) opposite to the cooling section (11b). Is thicker than the thickness of the liquid film at the site on the cooling unit (11b) side of the heating unit (11a), the liquid film at the site on the opposite side of the cooling unit (11b) in the heating unit (11a). The thickness is increased.

  According to this, the thickness of the liquid film in the part of the heating part (11a) opposite to the cooling part (11b) is the thickness of the liquid film in the part of the heating part (11a) on the cooling part (11b) side. Compared with the invention of claim 2 that becomes uniform, the liquid film remaining on the inner surface of the heating portion 11a can be boiled under reduced pressure more efficiently, so that the heat transport loss can be further reduced.

  In the invention according to claim 5, in the external combustion engine according to claim 4, as the cross-sectional area of the internal space of the heating part (11a) goes from the cooling part (11b) side to the opposite side to the cooling part (11b). The heating portion (11a) is formed such that the thickness decreases and the thickness of the internal space increases from the cooling portion (11b) side toward the opposite side of the cooling portion (11b). The adjustment structure is configured.

  According to this, since the cross-sectional area of the internal space of the heating part (11a) decreases from the cooling part (11b) side toward the cooling part (11b), the cooling part ( It is possible to effectively increase the thickness of the liquid film at the site opposite to 11b).

  Furthermore, since the thickness of the internal space of the heating part (11a) increases from the cooling part (11b) side toward the cooling part (11b), the cooling part (11b) of the heating part (11a). It is possible to further increase the thickness of the liquid film at the site on the opposite side (see Equation 1 above).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a block diagram showing schematic structure of the external combustion engine in 1st Embodiment of this invention. (A) is an enlarged view of the heating part of FIG. 1, (b) is AA sectional drawing of (a). It is a graph which shows the heating part cross-sectional area, liquid piston moving speed, and liquid film thickness in the heating part of FIG. (A) is an enlarged view of the heating part in 2nd Embodiment, (b) is BB sectional drawing of (a). It is a graph which shows the liquid film thickness in the heating part of FIG. It is explanatory drawing explaining the heating part temperature distribution and liquid film thickness distribution in a prior art. It is explanatory drawing explaining the liquid film thickness in the Z part of Fig.6 (a), a liquid piston moving speed, and a liquid film adhesion state. It is a graph which shows the time change of the liquid level position of the liquid piston in a prior art. In Formula 1, 2, it is a graph which shows the relationship between the flow rate when a flow path diameter is made constant, and a liquid film thickness.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram showing a schematic configuration of a power generation apparatus including an external combustion engine and a generator in the present invention. The up arrow in FIG. 1 indicates the top and bottom direction, and the down arrow indicates the bottom and top direction.

  The external combustion engine 10 is also called a liquid piston steam engine, and includes a container 11 that is a tubular pressure container. A working medium (water in this embodiment) 12 is sealed in the container 11 so as to be able to flow in a liquid state.

  The external combustion engine 10 also heats a part of the working medium 12 in the container 11 to generate steam of the working medium 12, and cooling to cool the steam of the working medium 12 generated by the heater 13. And a container 14.

  In the present embodiment, a high-temperature gas such as exhaust gas is used as the heat source of the heater 13. In addition, cooling water circulates in the cooler 14 of the present embodiment. Although not shown in the figure, a radiator that dissipates the heat taken by the cooling water from the steam of the working medium 12 is disposed in the circulating circuit of the cooling water.

  The container 11 has a substantially U-shape as a whole, and is disposed such that the bent portion is positioned at the lowest part in the top-and-bottom direction and both end portions extend upward in the top-and-bottom direction. A heater 13 is disposed at one end of the container 11. In addition, a cooler 14 is disposed at a site on one end side of the container 11 and below the heater 13.

  In this example, since the working medium 12 is water, the container 11 is made of stainless steel. The heating unit 11a in contact with the heater 13 and the cooling unit 11b in contact with the cooler 14 in the container 11 may be made of copper or aluminum having excellent thermal conductivity.

  An output unit 15 that converts the displacement of the liquid working medium 12 into mechanical energy and outputs it is disposed at the other end of the container 11 (the end opposite to the heating unit 11a). The output unit 15 includes a piston (solid piston) 16 that is displaced by receiving pressure from the liquid working medium 12 (liquid piston), and a cylinder unit 17 that slidably supports the piston 16.

  The piston 16 is connected to the shaft 2 a of the mover 2 of the generator 1, and an elasticity that generates an elastic force that presses the mover 2 toward the piston 16 on the opposite side of the piston 16 across the mover 2. A spring 18 is provided as a means.

  A permanent magnet is embedded in the mover 2, and the piston 16 drives the generator 1 by oscillating and moving the mover 2 to generate an electromotive force.

  The container 11 is expanded in the horizontal direction in the heating unit 11a. Along with this, the internal space of the heating unit 11a also has a shape that expands in the horizontal direction. In this example, the outer shape of the heating unit 11a is a disk shape that expands in the horizontal direction, and the internal space of the heating unit 11a is also a disk shape that expands in the horizontal direction. Although illustration is omitted, in this example, the heating part 11a is appropriately divided and formed.

  The radially outermost portion of the internal space of the heating unit 11a constitutes a vapor reservoir 19 that accumulates vapor vaporized by the heating unit 11a.

  2A is an enlarged view of the heating unit 11a of FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. 2A and 2B show a state in which the liquid surface 12a of the working medium 12 is located in the inlet portion of the heating unit 11a in the container 11, in other words, in the central portion of the heating unit 11a.

  As shown in FIG.2 (b), the planar shape of the internal space of the heating part 11a is star shape. That is, the internal space of the heating unit 11a has a shape extending radially from the center of the heating unit 11a in the horizontal direction, and the cross-sectional area of the internal space of the heating unit 11a is radially inward as shown in FIG. It shrinks as it goes radially outward from.

  In addition, the cross-sectional area of the internal space of the heating part 11a means the area of the cross section when the internal space of the heating part 11a is cut by a surface that is separated from the inlet part of the heating part 11a by a predetermined distance. In this example, the cross-sectional area when the internal space of the heating part 11a is cut by a concentric cylindrical surface is the cross-sectional area of the internal space of the heating part 11a.

  Although details will be described later, by configuring the heating unit 11a in this way, the heating unit 11a has a liquid film thickness adjusting structure that adjusts the thickness of the liquid film remaining after the working medium 12 is vaporized. .

  Incidentally, in this example, as shown in FIG. 3B, the cross-sectional area of the internal space of the heating unit 11a is set so that the flow velocity of the working medium 12 becomes substantially constant from the radially inner side to the radially outer side. In this example, the thickness of the internal space of the heating unit 11a (the dimension of the internal space of the heating unit 11a in the vertical direction in FIG. 2A) is constant in the radial direction of the heating unit.

  Next, the basic operation in the above configuration will be briefly described. When the heater 13 and the cooler 14 are operated, first, the working medium (water) 12 in the heating unit 11a is heated and vaporized by the heater 13, and the vapor of the high-temperature / high-pressure working medium 12 is generated in the heating unit 11a. Accumulated and pushes down the liquid level 12a of the working medium 12 on one end side (heating unit 11a side) of the container 11. Then, the liquid working medium 12 sealed in the container 11 is displaced from one end side to the other end side of the container 11 to push up the piston 16 on the generator 1 side and compress the spring 18.

  When the liquid surface 12a of the working medium 12 on one end side of the container 11 falls to the cooling unit 11b and the vapor of the working medium 12 enters the cooling unit 11b, the vapor of the working medium 12 is cooled and liquefied by the cooler 14. Therefore, the force that pushes down the liquid level 12 a of the working medium 12 disappears, and the liquid level 12 a of the working medium 12 rises on one end side of the container 11. As a result, the piston 16 on the generator 1 side that is once pushed up by the expansion of the vapor of the working medium 12 is lowered by the elastic force of the spring 18.

  Such an operation is repeatedly executed until the operations of the heater 13 and the cooler 14 are stopped. During this time, the liquid working medium 12 in the container 11 is periodically displaced as a liquid piston (so-called self-excited vibration). Thus, the mover 2 of the generator 1 is moved up and down.

  Next, the behavior of the working medium 12 in the heating unit 11a will be described in detail. Now, when the liquid piston (the working medium 12 in the liquid state) is pushed back most toward the heating unit 11a, when the working medium 12 is vaporized in the heating unit 11a and the vapor of the working medium 12 expands, FIG. ) And (b), the liquid piston moves from the radially outer side toward the radially inner side in the internal space of the heating unit 11a.

  At this time, since the cross-sectional area of the internal space of the heating unit 11a is reduced as it goes from the radially inner side to the radially outer side, the cross-sectional area of the internal space of the heating unit 11a increases as it goes from the radially inner side to the radially outer side. Compared with the case where the cross-sectional area of the internal space of the heating part 11a is constant from the radially inner side to the radially outer side, the liquid piston moving speed (flow velocity) in the radially outer part of the heating part 11a Can speed up.

  Here, as can be seen from Equations 1 and 2 and FIG. 9 described above, the thickness of the liquid film of the working medium 12 remaining on the inner surface of the heating unit 11a after the vapor of the working medium 12 expands is high in the liquid piston moving speed. It gets thicker. For this reason, as shown in FIG. 3C, the thickness of the liquid film of the working medium 12 at the radially outer portion of the heating unit 11a can be increased.

  Here, as shown in FIG. 6C described above, the temperature of the radially outer portion of the heating unit 11a is higher than that of the radially outer portion. For this reason, since the liquid film can be efficiently boiled under reduced pressure by increasing the thickness of the liquid film of the working medium 12 in the radially outer portion of the heating unit 11a, heat transport loss can be reduced.

  In other words, the heating unit 11a has a liquid film thickness adjustment structure that adjusts the thickness of the liquid film remaining after the working medium 12 is vaporized. Among them, the thickness of the liquid film is adjusted so as to increase the thickness of the liquid film on the opposite side of the cooling unit 11b, so that the liquid film remaining on the inner surface of the heating unit 11b can be efficiently boiled under reduced pressure, As a result, heat transport loss can be reduced.

  Specifically, in the liquid film thickness adjusting structure in the present embodiment, the heating part 11a is formed so that the cross-sectional area of the internal space of the heating part 11a decreases from the cooling part 11b side toward the opposite side to the cooling part 11b. It is configured by being.

  In this example, as shown in FIG. 3B, the liquid piston moving speed is made almost constant from the radially inner side to the radially outer side. Therefore, the liquid film thickness is also changed from the radially inner side to the radial direction as shown in FIG. It becomes almost constant toward the outside.

  Incidentally, the broken line in FIGS. 3B and 3C will be described. Since the liquid piston is reciprocated in the radial direction of the heating part 11a, the moving speed of the liquid piston is as shown by the broken line in FIG. 3B. It becomes almost zero at the radially outermost part of the. Then, the liquid film thickness becomes substantially zero in the vicinity of the radially outermost portion of the heating portion as indicated by the broken line in FIG. The broken lines in FIGS. 3B and 3C mean this.

(Second Embodiment)
In the first embodiment, the thickness of the internal space of the heating unit 11a is constant in the heating unit radial direction. However, in the second embodiment, as shown in FIG. The thickness of the space (the dimension of the internal space of the heating unit 11a in the vertical direction in FIG. 4A) is increased from the radially inner side toward the radially outer side.

  On the other hand, in this example, the cross-sectional area of the internal space of the heating unit 11a is set similarly to FIG. 3A of the first embodiment. For this reason, as shown in FIG. 4B, the planar shape of the internal space of the heating unit 11a is a star shape that is thicker on the radially inner side and thinner on the radially outer side than that of FIG. 2B of the first embodiment. It has become.

  In the present embodiment, since the cross-sectional area of the internal space of the heating unit 11a is set in the same manner as in the first embodiment, the liquid piston moving speed in the radially outer portion of the heating unit 11a as in the first embodiment. The moving speed of the liquid piston can be made uniform between the radially outer portion and the radially inner portion, and as a result, the thickness of the liquid film of the working medium 12 at the radially outer portion of the heating portion 11a is increased. Can do.

  Furthermore, in this embodiment, since the thickness of the internal space of the heating unit 11a is increased from the radially inner side to the outer side, the thickness of the liquid film of the working medium 12 is increased from the radially inner side to the radial direction as shown in FIG. It can be increased toward the outside.

  This phenomenon can be understood from Equation 1 described above. That is, according to Equation 1, the liquid film thickness δ (x) increases as the flow path width d increases, and the thickness of the internal space of the heating unit 11a is moved from the radially inner side to the radially outer side. This is because the increase is equivalent to increasing the flow path width d in Equation 1 described above.

  As described above, in the present embodiment, the thickness of the liquid film of the working medium 12 on the radially outer side can be increased as compared with the first embodiment, so that the liquid film remaining on the inner surface of the heating unit 11a is further increased. Efficient boiling under reduced pressure can be achieved, and heat transport loss can be further reduced.

  That is, in the liquid film thickness adjusting structure in this embodiment, the cross-sectional area of the internal space of the heating unit 11a decreases from the cooling unit 11b side to the opposite side of the cooling unit 11b, and the internal space of the heating unit 11a is reduced. The heating part 11a is formed so that the thickness increases from the cooling part 11b side toward the opposite side to the cooling part 11b.

  Incidentally, the meaning of the broken line in FIG. 5 is the same as the meaning of the broken line in FIGS. 3B and 3C in the first embodiment.

(Other embodiments)
(1) Each said embodiment is only what showed an example of the plane shape of the internal space of the heating part 11a, It is not limited to this, The plane shape of the internal space of the heating part 11a can be variously changed. is there.

  (2) In each of the above embodiments, the heater 13 and the container 11 are formed separately, but the heating unit 11a of the heater 13 and the container 11 may be integrally formed.

  (3) In each said embodiment, although high temperature gas is used as a heat source of the heater 13, you may comprise the heater 13 with an electric heater.

  (4) In each of the above embodiments, the case where the present invention is applied to the drive source of the power generation apparatus has been described. However, the external combustion engine of the present invention can also be used as a drive source other than the power generation apparatus.

  (5) In each of the embodiments described above, the diameter of the container 11 is expanded in the horizontal direction in the heating unit 11a, and the heating unit 11a has a disk shape that expands in the horizontal direction, but is not limited thereto. For example, the diameter of the container 11 may not be expanded in the horizontal direction, and the heating unit 11a may have a tubular shape that extends linearly in the vertical direction.

  In addition, when the heating part 11a has a tubular shape extending linearly in the vertical direction, the cross-sectional area of the internal space of the heating part 11a is obtained by cutting the heating part 11a along a plane orthogonal to the axial direction, that is, a horizontal plane. It means the cross-sectional area.

11 container 11a heating part (liquid film thickness adjustment structure)
12 Working medium

Claims (5)

A tubular container (11) in which a working medium (12) is encapsulated so as to be able to flow in a liquid state;
A heating unit (11a) that is formed at one end portion of the container (11) and heats and vaporizes a part of the liquid working medium (12);
A cooling part (11b) that is formed in the container (11) at the other end side than the heating part (11a) and cools and liquefies the vapor of the working medium (12) vaporized by the heating part (11a). )When,
An output unit (15) that communicates with the other end of the container (11) and converts the displacement of the working medium (12) in the liquid state caused by the volume variation of the vapor into mechanical energy and outputs the mechanical energy; ,
The heating section (11a) has a liquid film thickness adjustment structure that adjusts the thickness of the liquid film remaining after the working medium (12) is vaporized,
The said liquid film thickness adjustment structure adjusts the thickness of the said liquid film so that the thickness of the said liquid film in the site | part on the opposite side to the said cooling part (11b) among the said heating parts (11a) may be increased. An external combustion engine characterized by   The liquid film thickness adjusting structure is such that the thickness of the liquid film in a portion of the heating section (11a) opposite to the cooling section (11b) is the cooling section (11b) of the heating section (11a). The thickness of the liquid film in the portion on the opposite side of the cooling unit (11b) in the heating unit (11a) is increased so as to be uniform with the thickness of the liquid film in the portion on the) side. The external combustion engine according to claim 1.   The heating part (11a) is formed such that the cross-sectional area of the internal space of the heating part (11a) decreases from the cooling part (11b) side toward the opposite side to the cooling part (11b). The external combustion engine according to claim 2, wherein the liquid film thickness adjusting structure is configured.   The liquid film thickness adjusting structure is such that the thickness of the liquid film in a portion of the heating section (11a) opposite to the cooling section (11b) is the cooling section (11b) of the heating section (11a). ) The thickness of the liquid film in the portion on the opposite side of the cooling portion (11b) in the heating portion (11a) is increased so as to be thicker than the thickness of the liquid film in the portion on the) side. The external combustion engine according to claim 1.   The cross-sectional area of the internal space of the heating part (11a) decreases from the cooling part (11b) side toward the opposite side of the cooling part (11b), and the thickness of the internal space is reduced to the cooling part (11b). The liquid film thickness adjusting structure is formed by forming the heating part (11a) so as to increase from the side toward the opposite side to the cooling part (11b). The external combustion engine according to claim 4.

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