DE2344162A1 - HOT GAS ENGINE WITH ONE OR MORE HEATERS MADE BY A NUMBER OF PIPES ARRANGED IN THE FLOW PATH OF COMBUSTION GASES COMING FROM A COMMON BURNER DEVICE - Google Patents

Description

Pr. Hcrfiftrt Sehof *

according to PHN. 6> 29 .

r.ie.i .. «. lt

Applicant: N.V. Philips'Gbeila ^ penFabrlekeD

Aide No .. PHN- 6529 ^{WIJ 7 WJM} *

Registration dated 31 · A ^ g. 1973

"Hot gas flotor with one or more heaters running through a number of tubes are formed in the flow path of the combustion gases from a common ßrennervorrichtung originate, are arranged ".

The invention relates to a hot gas engine with one or more working spaces, each containing a compression space of variable volume and lower average temperature and an expansion space connected to it via a cooler, a regenerator and a heater, likewise variable volume and higher average temperature, the (the ) The heater is (are) formed by a number of tubes arranged in the flow path of the lioissen combustion gases emanating from a common burner device _c

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Such a hot gas rotor is ims the British patents 708.199 and 8S> 8 ..? 7n known.

The heater is a heat exchanger, in

the working fluid in the engine is supplied with caloric energy. The combustion gases flow to at dvii heating tubes along and under release of heat to dom through the tubes flowing working medium.

It turns out that in particular

in the case of multi-cylinder hot gas engines with only one central urn device, as they are known from British patent specification 708.199, the temperatures of the working medium in the different heater tube bundles with each other can vary greatly. There can be several reasons for this. For example, a deviation in the burning position of the racer one bundle of heater tubes is supplied with more heat than the other. This can also cause temperature differences arise, the unequal flow and leakage losses of the working medium between the cylinders appear. It is not just the flow resistances that can do this of the tube bundles belonging to the respective cylinders differ from one another, but those belonging to a cylinder can also be pipes belonging to one another, as far as the flow resistance is concerned, may be different.

The determined temperature undershoots affect the performance and the thermal efficiency of the Mo tor.

The invention now aims to provide a Heis .- ^ a s -

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mot or / u scha ΓΓ on, hoi dem the disadvantages mentioned in a simple manner l \ eisp must be switched off.

The hot gas engine according to the invention has this the indicator that the heater pipes over part of their I.fingt »lie within a common heat pipe, dus is provided with a heat source at another point is around the same temperatures of the relevant in the hot drive of the motor To retain egg-hit / pipe parts.

in the context of the present application

A heat pipe is understood as a heat transport device that is formed by a container in which there is a small amount of heat transport medium, for example sodium, which on the one hand evaporates from a container wall and / WfU ¹ by absorbing heat from a heat source and on the other hand under the transition from the Vapor into the liquid phase? another container wall gives off heat.

With such a heat pipe large

Kärinoinojigen with almost no temperature drop and no pumping device; or transported without other moving parts.

The return of the condensed heat transport by means of the wall on which the evaporation takes place, can take place under the influence of gravity. Most of the time, however, there is a capillary structure in the heat pipe, which the coniiensation wall connects with the evaporation wall and through which condensate is returned to the evaporation wall under all circumstances due to the capillary effect.

Heat pipes with a capillary structure for

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Recirculation of condensate is known per se, for example from U.S. Patents 3,299,759 and 3 ^ 02,767.

The greatest advantage of using the heat pipe in the present case is based on the fact that the major part of the heat transport medium vapor in the heat pipe always condenses on those parts of the heater tube which have the lowest temperature, i.e. on those parts of the heater tube, in which most of the heat is absorbed from the pipe walls by the working fluid of the engine. Through this and by the lack of temperature gradients at the thermal connections between the heat source and the heater - pipe parts it is achieved that the heater pipe parts themselves are isothermal and have the same temperature as each other. This takes it through the different heater tubes (Bundle) flowing working fluids at the same temperature.

The heat pipe is in structural terms

easy to arrange, even in existing engines with direct heating by combustion gases, while there is great freedom as to where the heat pipe is mounted on the heater pipes. Furthermore, the heat load on the heat pipe is extremely low.

It should be noted that from the Swiss

Patent 512,670 a heated by combustion gases Heissgasraotor is known, in which the heater tubes over part of the length in a with heat-storing material filled vessel are arranged. Such a heat accumulator

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is unsuitable as a temperature equalizer for several reasons to be effective for the heater tube parts located therein.

The heat accumulator with its heat transport

through conduction has a thermal resistance that is thousands of times greater than the heat pipe. This occurs when the heat accumulator through the working fluid in these heater tubes Heat is extracted, constantly colder places in the heat storage. Depending on whether the working medium draws more heat in a pipe a locally lower temperature sets in. The lower temperatures are due to insufficient heat flows insufficiently balanced from the heat-storing material. Located If there is a liquid heat-storing material, for example LiF, in the vessel, this material solidifies at the point of the heater tube parts at a lower temperature and the thermal resistance in the heat accumulator increases significantly.

Fulfilled in the hot gas engine according to the invention

the heat pipe almost equilibrates its temperature from starting the engine Task, in the case of the hot gas engine from the aforementioned Swiss patent, the heat accumulator forms during a considerable period after the engine has been switched on, an element that compensates for the temperature of the working medium in the way of the different heater tubes. Because of the relatively large heat capacity and the poor "thermal conductivity" of the thermal storage material It takes a considerable time for this material to reach operating temperature. In this period just occurs

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practically no heat exchange due to the poor thermal conductivity between the heater tube parts and therefore no temperature equalization.

As a heat source for the common heat pipe

For example, an auxiliary burner can be used or an electrical heating element within or outside the heat pipe.

According to the invention, the common heat - "tube a heat-permeable wall arranged in the flow path of the combustion gases in thermal contact with a part of the combustion gases.

This makes further aids superfluous,

while the heat pipe does not require any special structural precautions.

In a favorable embodiment of the invention

According to the hot gas engine, the heat source is designed in such a way that that it keeps the heater tube parts at a temperature which is at least the mean temperature of the immediate corresponds to the heated by the combustion gases heater tube parts outside the heat pipe.

The heat pipe then equals at a temperature that corresponds to the desired temperature of the working medium in the heater. pipes almost corresponds to. The heat source supplies the optimal amount of heat. An increase in the heat flow through the heat pipe, with the consequence of an increase in the temperature level, has no further beneficial effect with respect to a Reduction of the temperature differences between the heater

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pipes.

An embodiment of the invention is shown in

the drawings and is described in more detail below. Show it:

Fig. 1 is a plan view of a double-acting ^ -cylinder hot gas engine,

FIG. 2 shows a section along the line U-II in FIG. 1.

The hot gas motor according to FIG. 1 contains four

Cylinders 1, 2, 3 and h for four thermodynamic ^ circuits. The regenerator and the cooler, which belong to a certain circuit, are each located in a common space, namely in spaces 5 »6, 7 and 8. The four cylinders and the spaces for the regenerator and the cooler are in a ring. A regenerator and a cooler 10 are located in space 7 from FIG. 2. A regenerator and a cooler are also located in spaces 5-6 and 8, which are not shown in the figure.

The piston 11 moves up in the cylinder 3

and from. The expansion space 12 is located above the piston, to which the heater tubes 13 are connected, the other ends of which open into a channel I ^. Under the piston 11 is the Compression space 15 »to which a channel 16 adjoins.

Heater pipes 7 are connected to the regenerator 9 at the other ends of which open into the channel 1 k. A duct 18 connects to the cooler 10,

Hei a double-acting motor is the

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Expansion space of one cylinder via a heater, regenerator and cooler with the compression space of another Cylinder connected, from which other cylinder the expansion space again via a heater, regenerator and cooler connected to the compression chamber of a next cylinder is.

In the present case, there is the expansion space

12 in cylinder 3 via heater tubes 13 »channel 14, heater tubes 17» regenerator 9j, cooler 10 and channel 18 with the compression chamber (not shown) in cylinder k in open connection.

The compression space 15 in the cylinder 3 is standing

via the channel 16, the cooler, not shown, and the Regenerator in space 6 and the heater tubes (not shown) with the expansion space (not shown) in the cylinder 2 in connection.

The four thermodynamic cycles

The heater tubes belonging to it stand in a wreath around a room 20 for combustion gases. The hot combustion gases come from a central burner device 21 with a supply for combustion air 22 and a supply for fuel 23. A discharge 2 h for combustion gases is connected to the room 20.

The upper parts of all heater tubes

lie together with the channels that connect the heater tubes belonging to a cylinder, regenerator combination connect (e.g. channel 1 ^ 1 in Fig. Γ2) within a

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common annular heat pipe 25, the inner wall of which is covered with a capillary structure 26. Located in the heat pipe some sodium as a heat transport medium. The heat pipe further has a heat-permeable wall 27, which is in the flow path of the originating from the burner device 21 hot combustion gases is arranged.

When the hot gas engine is running, the

hot combustion gases on the heat-permeable wall 27 and along the lower free heater tube parts with dissipation of heat therealong. By absorbing heat from the heat-permeable "wall 27 evaporates in the heat pipe 25 present sodium. The sodium vapor flows to the heater tube parts and their connecting channels because of the Pressure prevailing there due to slightly lower temperatures at this point. Because that through the heater tubes and Working medium flowing through its connecting channels absorbs heat from the heater tube walls and channel walls. The sodium vapor then condenses on these walls, giving off heat to them. Where the lowest temperatures if most of the steam condenses, the temperatures of these walls are equalized in this way. The result is that the upper heater tube parts and their connecting channels are isothermal and have the same temperature. The temperature of the working medium flowing through the heater tubes is equalized everywhere, so that there are differences in working medium temperature between the pipes among each other have almost disappeared, which is the performance and the thermal

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Improved engine efficiency. The surface of the heat permeable Wall 27 of the heat pipe 25 is chosen in this way been that the heat flow to the heat pipe is a sodium temperature gives that of the mean temperature of the lower pipe parts directly heated by the combustion gases almost corresponds. The one absorbed by the heat pipe The amount of heat is then optimal to achieve the desired temperature compensation. The heat load on the heat pipe is small amount. A higher thermal load does not improve the temperature compensation.

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Claims (2)

23U162 PHN. 6529. - 11 PATENT CLAIMS. 1,) Hot gas motor with one or more working clear a compression room of variable volume and lower average temperature as well as one with it a cooler, a regenerator and a heater connected expansion space also of variable volume and higher medium temperature, the heater (s) being formed by a number of tubes placed in the flow path of the from a common burner device hot combustion gases are arranged, characterized in that the heater tubes over part of their Length lie within a common heat pipe that is provided with a heat source at another point around Maintain the same temperatures of the relevant heater tube parts when the engine is running. 2. hot gas engine according to claim 1, characterized in that that the common heat pipe has a heat-permeable wall arranged in the flow path of the combustion gases having, with part of the combustion gases in thermal Contact is available » 3 · Hot gas engine according to claim 1 or 2, characterized characterized in that the heat source is designed in such a way that ~ that it keeps the heater tube parts at a temperature the at least almost the mean temperature of the heater tube parts directly heated by the combustion gases outside the heat pipe. 409813/0366