US2171047A - Heat exchange apparatus - Google Patents

Description

Aug. 29, 1939. I H, c, c ns'o ET AL 2,171,047

HEAT EXCHANGE APPARATUS 3 Sheets-Sheet 2 Filed Feb. 24; 1937 INVENTORS I HOLDEN C P/c/m/eaao/v.

fle/vev AAMPE 2 BY I ATT RNEYS- 29, 1939- H. c. RICHARDSON ET AL ,171,047

HEAT EXCHANGE APPARATUS Filed Feb. 24, 195'? s Sheets-Sheet s W 9 m Emm QR m O. CE A Patented Aug. 29, 1939 UNITED STATES, PATENT OFFICE Holden 0. Richardson, Washington, D. 0., and Henry Kampl', New York, N. Y.

' Application February 24, 1937, Serial N0. 127,356

13 Claims. (emu-57) This invention relates to heat exchange apparatus and particularly to heat exchange apparatus designed for use with the power plants of airplanes'for cooling or condensing purposes.

In the air-cooled motors used with airplanes at the present time, advantage is taken of the slip stream from the propeller for supplying air for cooling purposes and one of the objects of the present invention is so to construct and to arrange cooling means, such as radiators, or condensers for a steam-driven power plant for airplanes, that they can make best use of the air coming from the slip stream to efiect in comparatively close quarters a comparatively large heat exchange, with a minimum disturbance of flow of air over the adjacent wing surfaces.

As herein illustrated, the invention is shown as embodied in'a condenser for condensing the steam from a'steam turbine or a steam engine utilized to drive thepropeller of the airplane and an important object of the invention is so to construct the condenser that substantially uniform condensing results can be obtained throughout the condensing structureeven though because of space limitations the cooling air must pass .over some of theparts of the condenser after it has already passed over others, and eventhough the tube lengths vary inproportion to the radial distance of their axes-from the axis of the condenser.

-An important feature of the invention is the symmetrical arrangement of the elements of the condenser with respect to the propeller axis which contributes markedly to the'efiective operation of the difierent parts of the condenser. Another important feature of the invention is the con-,

trol of the distribution of the steam to be condensed to the different parts of the condenser whereby "the steam is apportioned to the various parts in proportion to their condensing or heatexchanging capacity.

Another important feature'of the invention is the utilization of directing means, preferably stream-lined and so constructed and arranged as to convert the velocity of the slip stream into .pressure whereby, as the airenters the conduit to the condenser, its expansion-beyond the entrance tends to convert velocity to pressure at the face of the condenser, and then by the use of Venturi-shaped passages reconvert pressure to increased velocityand to direct the air stream into the air passages in the condenser without undue eddy losses at the entrance to'same.

Notmnly does the invention aim to improve,

the means which, control the supply of cooling air to the condenser, but the invention aims also to provide improved arrangements for discharging. the air after it. has taken up the heat from the condenser. Important features of the improved discharge arrangement are the provision 5 of means for insuring a smooth discharge and the breakingup of eddies'and whirls before the air is discharged into the stream passing over the plane wing and also an arrangement whereby the discharge comes at such a point on the wing 0 that it tends to remove the'boundary layer of air and thereby augment the wing lift, while also augmenting the differential pressure between the entrance and exit.

Figure 1 is-a section through theforward part of the wing of an airplane and through the motor or turbine cowling, illustrating a condenser embodying the present invention, with passages 10- cated at the rear, and at both sides'of the propeller shaft;

Figure 2v is a sectional .plan view of Figure 1; I Figure 3 is a section on the line 3-3 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is a plan, partly in section; of a con- J denser embodying the present invention;

. Figure 6 is a vertical section illustrating a condenser arranged concentrically about the propeller shaft and located near the front '01 the I cowlingpwith the discharge for the air that has traversed the condenser located near the front of the cowling;'

Figure 7 is a vertical section showing a similar arrangement of the condenser but arranged to discharge the cooling air on the under side of the wing;

Figure 8 is a section through the condenser Of Figure 7;

Figure 9.is a detail section of the input end of 40 one of the condenser tubes,. and

Figure 10 illustrates the nozzles for controlling the input oi! steam into the condenser tubes.

Figure 11 illustrates a method of controlling the input of steam to the condenser tubes by restricting the diameter of the tube.

In the embodiment of the invention illustrated particularly'in Figures 1, 2, 6 and 7 inclusive, the motor 2, for driving the propeller 4 by connections thereto, including'the propeller shaft 6, may be of any suitable type, such, for example, as a steam turbine ina steam powered airplane, the exhaust .steam fromthe turbine 2 going through a conduit 8, Figuresl and '7, to a manifold IOat the top of the condenser I2.

That part of. the propeller connections and turbine 2 which extends beyondthe forward edge of the airplane wing it is enclosed in a cowling I6, stream-lined to direct the slip stream from the propeller over and under the wingv surfaces. The cowling It, at its forward end, projects slightly over a spinner It, surrounding and connected to the hub of the propeller 4 and provided with a stream-lined nose 20, this arrangement providing an intake passage 22 for the cooling air for the condenser l2. The cooling air, being a part of the slip stream, e ters the passage 22 at a velocity considerably in excess of the velocity of movement of the wing I through the 'air.

In the embodiment'of the invention shown in Figs. 1 to 4 inclusive, the air intake passage 22 is at the forward end of an airconduit 24 passing symmetrically past the turbine 2 to conduct the air from the intake 22 to the condensers 12. This conduit 24 is continued beyond the condensers I2 to the upper surface of the wing l4 where it discharges the air after it has picked up the heat from the condenser I2, this discharge being effected in such away as to tend to remove the boundary layer of air clinging to the upper surface of the wing and thus aid the forces which lift the plane, by delayingburbling. At its discharge end each conduit 24 is preferably provided with stream-lined guides 26 which serve to smooth out eddies that may have formed in the air stream in its passage through the conduits 2'4 and thus insure its discharge on the upper surface of the wing in a smooth flowing stream merging into the air stream-passing over the to heat exchange.

upper surface of the wing with augmented veloc-* ity in a region of reduced pressure.

In the form of the invention shown in Figs. 1 to 5 inclusive, the condenser is made up of upright condenser 'tubes 28 which extend from thesteam manifold It to the water manifold 30, these tubes being preferably provided with fins 32 such as shown in Fig. 9 to increase the rate of heat exchange. At the intake end of the condenser l2 stream-lined guides '34 are'provided which serve two purposes: First, they are so 10- cated with respect to the first row of condenser tubes 28 that they guide the cooling air against the median lines of these tubes and, secondly, by their shape and relation to each other they produce a Venturi effect whereby pressure is conis desired 'to admit to a particular tube, Fig. 10

. showing a slightly different form of the nozzle passage from that shown in Fig. 9.

In the form of the invention shown in Figures 1 to 5 inclusive, the conduit 24, as hereinabove suggested, carries the air past the turbine 2 to direct it into the condensers l2, although the scoop-like intake passage 22 is concentric with the turbine driven shaft and extends about the axis of said shaft. The entrance 22 being of somewhat smaller cross sectional area than that part of the conduit 24 behind the entrance, the I air is driven into the entrance 22 by the slip stream and thus, as it expands behind the enincreasing pressure to the face of the condenser, where velocity is regained as the air passes through the Venturi passages, to the cooling elements.

In the forms of the invention shown in Figures 6, '7 and 8, the condenser I2 is arranged concentrically about the axis of the propeller shaft 6 v, and is of the construction described in more deverted to increased velocity corresponding to that in the passages through the condenser, the air passing in sinuous streams over the staggered rows of condenser tubes in'such manner that it passes from the tips of the fins of one stage of tubes to the base of the fins of the next, and vice versa, thus establishing a turbulence beneficial It will be obvious that the anentering the forward. end of the condenser will have pickedup considerable heat from the first rows of tubes of the condenser before it reaches the rearend of the condenser and that, therefore, its capacity for absorbing heat from these rear tubes will be tail hereinafter.

y In the form of the invention shown in Figure 6, the air from the propeller slip stream enters an annular entrance 22 into a conduit 40 which is formed between a sheet metal guide wall 42, constitutingal so a partition between the conduit 40 and anannular exhaust air passage 44 surrounding the conduit 40, and an inner guide wall 46 .surrounding the propeller shaft 6. The conduit 40 is of such shape that the air, after it has gone through the entrance passage 22, is allowed to expand before it enters the condenser I2. The outer wall, of the discharge passage 44 is formed by the cowling It.

The wall 46 of the conduit 40 is extended through the condenser l2 and is then 'curvedup to .meet the cowling l6 and thuscomplete the conduit 44, as shown in Figure 6. .The'discharge passage 44 is completed by a torus-like member 48 having its inner edge connected to the wall 42 and havingits outer edge connected to the shield 50 in such manner that the front edge of the cowling "5 forms a streamline nose for the torus. The air from the discharge passage 44 is thus discharged directly into the slip stream, in aregion of reduced pressure augmenting the flow. In Figure 7 the conduit 40 for the cooling air is formed directly between the inner wall 46' and the cowling l6 and the conduit is completed beyond the condenser [2' by a guide wall 52 which directs the stream of air, after it has passed through the condenser l2, to a discharge 54 in the lower part of the cowling, so that the air, after it has picked up the heat from the condenser [2, passes through vanes 26 and enters the stream of air flowing over the under side ofthewingl4. v

'Ihe condenser. l2, asshown particularly in Figures '1 and 8, comprises a series of substantially'semi circula'r condenser tubes 28' which exconsiderably reduced. Tojcompensate'for'this,

so as to insure proportionate condensing action in each of the tubes, theinput ofsteam into each of the tubes 28 is preferably metered, at. least in those tubes ,in the rows behind the initial row. This metering may be effected byinsert-f ing into the ends of the respective tubes opening into the steam manifold Ill, nozzles 36, or any other'well known means of restriction, the restricted orifices 38- of which may vary in diametc; in accordance with the amount of steam it water header .52, of similar construction, on the tendbetween a steam header iflsector-shaped in cross-section, anda water header 58, likewise sector-shaped in cross-section, on the one side or the condenser and between a steam header 60,. also sector-shaped incross-section, and a other. side .of the condenser. Supporting and spacing diaphragms maintain the tubes 28' in proper, relation to each' other, these 'diaphragms extending between the inner air. guiding wall 56 of the condenser and the outer air guiding wall 7 68, both of these walls being preferably corrugated as. shown in Figure 7 to assist in efiecting a sinuous flow of the air over the tubes of the condenser adjacent to the outer and inner walls 5 thereof.

' The steam to be'condensed enters thesteam headers 56 and 60 through pipes I and the condensed steam or water leaves the water headers 58 and 62 through 'pipes'IZ. r

The condenser l2 preferably *has stream-lined guides 34 ofthe same character as'those provided for'the condenser I 2, except that their longitudinal contours correspond with the longitudinal contours of the condenser pipes28. I

From the foregoing description, it will be ob.- vious that a compact and eflicient condenser or cooling construction has beenv provided which takes into consideration the space .and weight limitations in airplane construction and, at the 20 'same time, utilizes existing air flows toproduce, with as little disturbance of sustaining forces as possible and with as little loss of propulsive power as possible, a maximum of heat exchanging efiect. What is claimed as new is: g I 25 1. Condensing means for use in condensing steam in steam-driven aircraft having a propeller and a driving shaft therefor, saidcondensingmeans comprising, in combination, banks of.

steam condensing tubes extending concentrically to about the axis of the propeller shaft and a conduit forcondenser cooling air of annular cross section to and through said condensing means having an annular intake behind said propeller to receive va portion of the slip stream therefrom and, having a discharge so located as to discharge the air into a low pressure area, sad banks of con-' densingtubes forming an annular structure filling a cross sectional zone of said conduit of substantially greater cross section than the intake ,0 part of said conduit.

2.- Condensing means for use in condensing steam in steam-driven aircraft having a propeller.

and a driving shaft therefor, said condensing means comprising, in combination, banks of steam ,5 condensing tubes extending concentrically about the axis .of the propeller shaft and a conduit for condenser cooling air having an annular intake behind said propeller to receive a portion of the slip stream therefrom and having a discharge so 0 located as to dischargethe air into a low pressure area, said'condensing tubes forming an annular structure filling a cross sectional zone of said conduit and said conduit being of annular cross section to and through said condenser and increas- 5 ing progressively in cross-sectional area from said annular intake to said condenser.

- Condensing means for use in condensing r steam in steam-driven aircraft having a propeller and a driving shaft therefor, said con- [i densing means comprising, in combination, banks a of steam condensing tubes extending concentrically about the axis of the propeller-shaft and a conduit for condenser cooling air of annular cross section to and through said condenser and hav- 5 ing an intake behind said propeller to receive a ,portion of the slip stream therefrom and having a dischargeso located as to discharge the air into a low pressure area; said condensing tubes forming an annular structure filling a cross sectional zone yof said conduit of substantially greater cross sec- Condensing means for use in condensing steam in steam-driven aircraft having apropeller and-a driving shaft therefor, said condensing means comprising, -in combination, banks of steam condensing tubes extending concentrically 5 about the axis of the propeller shaft and a conduit for' condenser cooling air of annular cross section to and through-said condenser having an intake behind said propellerto receive a portion of the slip stream therefrom andhaving a dis- 1 charge so located as'to discharge the air into a low pressure area, said banks of-condensing tubes forming an annular structure filling across sectional zone of said conduit of substantially greater cross section than the intake part of said conduit and comprising two groups each made up of a steam header and a substantially diametrically opposed water header, banks of substantially semi-circular tubes connecting said headers, the

vtubes of sucessive banks in the direction of air movement being'staggered, and correspondingly curved stream-lined vanesso arranged as to dimet the air' against the respective condensing tubes of the first bank and at the same time reduce eddy'losses.

5. In an airplane having a steam driven propeller, a steam powered motor, and -a bowling enclosing .said motor, means for condensing the steam from said motor'comprising, in combination, a conduit for cooling air for said condenser extending through said cowling from an intake behind the propeller to a discharge adjacent to one of the wing surfaces, and-a condenser in said conduit comprising a steam header, a water header and successive banks of tubes connecting said headers, means for insuring uniform distribution of the cooling air over the tubes of the various banks and means at the intake ends of the tubes vof certain"banks adapted to apportion the input of steam intosaid tubes to the heat-absorbing capacity of the air when it reaches said banks.-

6. Heat exchange apparatus for airplanes comprising, in combination with the motor, the motor cowling and propeller, guides cooperating with said cowling to form an annular air passage with a restrictedannular opening arranged to receive a part of the propeller slip stream, banks of heat exchanging tubes arranged in said passage with the tubes of each bank in staggered relation to those of adjacent banks in the direction of movement of air through the passagaand means for concentrating the air upon the tubes of the first bank, said means being stream-lined to eliminate eddies.

7; Heat exchange apparatus for'airplanes comprising, in combination with the motor, the motor cowling and propeller, guides cooperating with said cowling to form an annular airpassage with a restricted annular opening arranged to receive a part of the propeller slip stream, banks of heat exchanging tubes arranged in said passage with the tubes of each bank in staggered/relationto those of adjacent banks in the direction of movement of air through the passage, means for concentrating the airupon the tubes of the first bank, said means being stream-lined to eliminate eddies, and means comprising sinuously curved surfaces for insuring anundulatory movement of I the air through said' heat exchanger.

8. In an airplane, in combination with a wing thereof, a propeller mounted on the wing, a motor for'driving the propeller, a cowling enclosing said motor, and heat exchanging elements located withi'r said cowling, of means concentri- 4 cally arranged about the propeller shaft to provide a continuous air passage from an annular scoop entrance arranged to receive a portion of the slip stream from the propeller into an expan'ding annular passage extending through the condenser and thence through a contracting, velocity accelerating passage to air exhaust apertures to the rear of the cowling, said heat exchange elements being located within and intermediate between the ends of saidpassage, and stream-lined vanes defining said exhausttapertures and serving to eliminate eddies in the stream of heated air discharged therethrough.

9. An air cooled heat exchanger concentrically and symmetrically, arranged about an axisand comprising, in combination, sector shaped intake manifolds, sector shaped exhaust manifolds, and

tubular heat exchange members concentrically curved about said axis to form successive banks of tubes connecting said manifolds and affording multiple passages for the fluid to be cooled between the intake and exhaust manifolds, and means comprising entrance defining stream-lined vanes and a sinuously curved surrounding cas ing for directing the air through said banks of tubes in a direction substantially parallel to the axis about which they are curved.

10. An air cooled heat exchanger concentrically and symmetrically arranged about an axis and comprising, in combination, sector shaped intake manifolds, sector shaped exhaust manifolds, and tubular heat exchange members concentrically curved about said axis to form' successive banks of tubes connecting said. manifolds and affording multiple passages for the fluid to. be cooled between the intake and exhaust manifolds, means for directing the air through said banks of tubes in a direction substantially parallel tothe axis about which they are curved, said means comprising a sinuously curved surrounding casing, and stream-lined guide members also concentrically and symmetrically arranged about said axis and so located as toconcentrate the cooling air in eddyfree streams upon the axes of the curved tubular cooling members of the first bank.

' 11. In an airplane, the combination with a propeller and propeller shaft, the airplane win and propeller supporting means intermediate between the propeller and front spar of said wing, of cooperating interior and exterior guiding elementc, coaxially and concentrically mounted aboutthe propeller shaft to form a continuous air passage from an annular scoop in the propellerrslip'stream into a symmetrical expanding and contracting passage ending in air exhaust apertures, said apertures being formed as a series of contracting passages in the upper surface of the wing to the rear of the front spar in a region of low pressure, and long deep-curved air foil elements in said passages arranged to obtain a boundary layer removal effect and to discharge the air at high speed smoothly into the passing air stream. V

12. Condensing means for use in condensing steam in steam-driven aircraft having a propeller and a driving shaft therefor, said condensing means comprising, in combination, banks of steam condensing tubes extending concentrically about the axis of the propeller shaft and a conduit for condenser cooling air of annular cross section to and through said condenser having an annular intake behind said propeller to receive a portion of the slip stream therefrom and having a discharge so located as to discharge the air into a low pressure area, said banks of condensing tubes being located in said conduit and comprising two groups each made up of -a steam header and a substantially diametrically opposed water header, and substantially semi-circular tubes connecting said headers, means for insuring uniform distribution of the cooling air over the respective tubes of said condenser, and means at the intake ends of the tubes of certain banks adapted to apportionthe input of steam into said tubes to the length thereof as determined by their radial distances from the axis of the condenser.

13. Condensing means for use in condensin steam in steam-driven aircraft having a propeller and a driving shaft therefor, said condensing means comprising, in combination, banks of steam condensing tubes extending concentrically about the axis of the propeller shaft and a conduit of annular cross section for the condenser cooling air, said conduit having an annular intake behind said propeller to receive a, portion of the slip stream therefrom and having a' discharge so located as to discharge the air into a low pres-' sure area, said condensing tubes forming an annular structure filling a cross-sectional zone of said conduit and said conduit being of annular cross section to and through said condenser and to said discharge, the portion of said conduit on the discharge side of said condenser comprising an outer reversel'ydirected portion surroundin the partextending through said condenser and including a torus-like end portion directing the discharged air into the direction of flow of the propeller slip stream. v

' HOLDEN C. RICHARDSON.

HENRY KAMPF.

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