EP0631654A1

EP0631654A1 - Improvements in pulse blade system for pulsating combustors

Info

Publication number: EP0631654A1
Application number: EP93903131A
Authority: EP
Inventors: John D. Chato
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-02-04
Filing date: 1993-02-04
Publication date: 1995-01-04
Also published as: GB9202329D0; WO1993015358A1; CA2129251A1; AU3447193A

Abstract

A pulsating combustor (10) having flat side walls (16, 18) and flat end walls (20) defining the combustion chamber (12), along with devices for introducing a fuel mix (32) into the combustion chamber and for initiating pulsating combustion (33), is improved by the provision of an insert at the four corner regions, such that smoothly rounded surfaces (34) are presented to the combustion chamber (12). In a variant, a pulsating combustor defines a combustion chamber and an exhaust portion, the latter incorporating a plurality of internal, parallel, spaced-apart hollow baffles (152) which define, between themselves and parallel outside walls of the exhaust portion, a plurality of exhaust passageways (154).

Description

IMPROVEMENTS IN PULSE BLADE SYSTEM

FOR PULSATING COMBUSTORS

This invention relates generally to pulsating combustors, and provides several refinements and improvements in such systems. Prior Art

The closest prior art known to me is represented by my own prior U.S. patent 4,846, 149, issued on January 9, 1990, and the corresponding Canadian patent 1,280,065, issued February 12, 1991.

These patents disclose a pulsating combustor in the form of a blade having a combustion chamber defined between two parallel walls, side walls and an end wall, and an exhaust portion again defined by two parallel walls. The parallel walls in the exhaust portion, however, are closer together than in the combustion chamber, and the unit incorporates two oblique intermediate walls forming a transitional area between the wider combustion chamber and the narrower exhaust portion.

A major use for the blade pulsating combustor disclosed in the said U.S. patent 4,846,149 is that of heating various fluids, particularly water. By setting up a pulsating combustion in the combustion chamber, the shock wave activity in the unit diminishes or eliminates the typical "boundary layer" of gases immediately adjacent the inside wall surfaces, thus greatly improving the conduction of heat outwardly through the walls of the blade pulsating combustor. GENERAL DESCRIPTION OF THIS INVENTION

The present specification sets forth a number of improvements on the basic blade configuration. More particularly, this invention provides a pulsating combustor comprising: two parallel and substantially flat side wall panels separated to define opposed longer sides of an elongate combustion chamber having an exhaust end and an entry end, two substantially flat end wall panels spanning between the respective corresponding ends of the side wall panels and defining opposed shorter sides of said elongate combustion chamber, said chamber being substantially rectangular when seen in a transverse section taken perpendicular to all said panels, bottom wall means at said entry end of the combustion chamber, exhaust means communicating with said exhaust end for ducting the products of combustion away from the combustion chamber, first means for introducing a fuel mixture into the combustion chamber, and second means for initiating pulsating combustion in the combustion chamber, characterized in that: insert means are provided for occupying the four corner regions adjacent the end wall panels, and for presenting smoothly rounded surfaces partially delimiting the combustion chamber, thereby to counteract any tendency for the fuel mixture to become trapped in squared-off corners.

Further, this invention provides a pulsating combustor comprising: two substantially cylindrical and substantially concentric side wall panels defining between them a substantially cylindical combustion chamber having an exhaust end and an entry end, exhaust means communicating with said exhaust end for ducting the products of combustion away from the combustion chamber, first means for introducing a fuel mixture into the combustion chamber, and second means for initiating pulsating combustion in the combustion chamber, characterized in that: said first means includes the provision of: a) a diffuser baffle substantially coinciding with said entry end and lying perpendicular to the axis of the cylidrical combustion chamber, and b) a plurality of substantially cylindrical intake tubes perpendicular to said diffuser baffle and each having a downstream end adjacent the diffuser baffle and an upstream end remote from the diffuser baffle, the upstream end having a bell- like configuration, the downstream ends of the intake tubes being spaced away from said diffuser baffle. Finally, this invention provides a pulsating combustor comprising: two parallel and substantially flat side wall panels separated to define opposed longer sides of an elongate combustion chamber having an exhaust end and an entry end, end wall means spanning corresponding ends of the side wall panels and defining opposed shorter sides of the combustion chamber, bottom wall means at an entry end of the combustion chamber, an exhaust portion communicating with said combustion chamber for ducting the products of combustion away from the combustion chamber, first means for introducing a fuel mixture into the combustion chamber, and second means for initiating pulsating combustion in the combustion chamber, characterized in that: said exhaust portion is defined between two substantially flat, parallel walls, and includes a plurality of internal, parallel, spaced-apart hollow baffles which define, between themselves and the parallel walls, a plurality of exhaust passageways. GENERAL DESCRIPTION OF THE DRAWINGS

Several improvements are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which: Figure 1 shows a typical pulsating combustor in the form of a "blade"; Figure 2 is a cross-section taken at the line 2-2 in Figure 1 , and showing the addition of an insert forming part of the present invention;

Figure 3 is an enlarged view of the circled left end of Figure 2; Figure 4 shows an alternative construction of the insert shown in Figure 3; Figure 5 is a perspective view showing a conduit arrangement for water to be heated by the pulse blade combustor shown in Figure 1, to take advantage of the radiant heat;

Figure 6 is similar to Figure 5, but is taken from a slightly different angle; Figure 7 is similar to Figure 6, but does not include the conduit arrangement;

Figures 8, 9, 10 and 11 are elevation, perspective, plan and perspective views of an intake arrangement useful for the "cylindrical" pulse blade combustor shown in Figure 23; Figures 12, 13, 14, 15 and 16 show various aspects of a diffuser arrangement and temperature enhancer, in particular for coal, to assist the carbon burnout;

Figures 17, 18, 19, 20, 21 and 22 show various aspects of exhaust and intake decouplers;

Figure 23 shows a modification of a cylindrical version of the pulse blade combustor;

Figure 24 is an axial sectional view through the modification of Figure 23; Figure 24a is an axial sectional view through an alternative construction to that of Figure 24;

Figure 25 is an axial cross-sectional view through an expanded unit similar to that of Figure 1, but with a multiplicity of parallel exhaust passages;

Figure 26 is a view like that of Figure 25, but showing a slight variation of the unit of Figure 25; Figure 27 is a sectioned perspective view through the unit of Figure 25;

Figure 28 is a view similar to that shown in Figure 27, but illustrating intake tubes; and

Figures 29 and 30 are perspective views of two different arrangements of intake tubes for use with the embodiment of Figure 28. DETAILED DESCRIPTION OF THE DRAWINGS

Attention is first directed to Figure 1 which shows a pulse blade combustor generally at the numeral 10, including a combustion chamber 12 at the bottom, and an exhaust portion 14 at the top. More specifically, the exhaust portion 14 is defined by two parallel walls 16 and 18 which are spaced apart but relatively close to each other, and two side walls 20 (only one visible in Figure 1).

Below the exhaust portion 10 is a transition portion 22 defined essentially by two obliquely sloping walls 24 and 26 that diverge downwardly. Finally, the combustion chamber 12 is defined by two parallel walls 28 and 30, a bottom wall (not visible in Figure 1), and an extended portion of the side walls 20. As can be seen at the right in Figure 1, the side wall 20 has edges that follow the sectional shape of the walls 16, 18, 24, 28 and 30. It will further be noted that the walls 28 and 30 are spaced further apart than are the walls 16 and 18. Fuel feeding means 32 (such as a plurality of small-diameter tubes) pass through the bottom wall 33a of the combustion chamber 12 and allow fuel to enter, along with combustion air. Ignition means such as a spark plug 33 is also provided in the combustion chamber 12, in order to initiate the pulsating combustion.

Attention is now directed to Figure 2, which represents a horizontal sectional view at the line 2-2 in Figure 1. In Figure 2 it will be seen that end regions contain two curved insert sections 34 which are secured in the positions shown in Figure 2, and which have the effect of "rounding" the end portions of the elongate combustion chamber. As can be seen in Figure 3, the curved insert sections 34 define a semi-cylindrical inside surface 36 and outer surfaces 38, 40 and 42, which are such as to allow the sections 34 to be snugly fitted into and secured to the respective end of the combustor shown in Figure 1. It is contemplated that the insert sections 34 would extend only as high as the top of the combustion chamber 12.

Attention is now directed to Figure 4, which shows an alternative construction for the curved insert section identified by the numeral 34 in Figure 3. In Figure 4, a plate member 44 is secured to the insert sections 34 along the surface 40 thereof (for example by welding or the like), and the construction of the pulse blade combustor is such that the side walls 28 and 30 of the combustion chamber 12 are directly affixed to the surfaces 38 and 42 of the insert section 34.

Generally speaking, the elimination of corners by the provision of the section 34 is a means of causing that portion of the fuel which might normally wish to "hide" in the corners and avoid the turbulence of combustion, to join with and mix into the contents of the remainder of the combustion chamber. This results in a more efficient utilization of the fuel.

Attention is now directed to Figures 5, 6 and 7, which illustrate a suitable conduit arrangement for ducting water or other liquid in such a way that heat can be transferred to the water or liquid from the outer surfaces of the blade pulse combustor shown in Figure 1. In Figures 6 and 7, the combustor can be partly seen at the numeral 10a. The combustion chamber 12 is at the left, while the exhaust portion 14 is at the right. Referring to Figure 7, a heat exchanger box 50 is defined by a panel 16 which is identical with the side wall 16 shown in Figure 1. Walls 24 and 28 are also marked in Figure 7. End panels 52, 54, 56 and 57 are attached to the pulse blade combustor 10a and there is also an intermediate panel 58 as shown in Figure 7. Within the two-compartment box defined by the panels 52, 54, 56, 57 and

58, a conduit 59 is affixed in the manner shown in Figures 5 and 6. Looking at Figure 5, the conduit 59 first undergoes a boustrophedonic configuration between the panels 52 and 58, consisting of a plurality of parallel pipe portions 60, connected in series by curved end joiners 61 The conduit 59 receives liquid from an inlet pipe 62.

It will be noted that the pipe portions 60 are adjacent the exhaust portion of the pulse blade combustor 10a.

By contrast, there is provided, adjacent the combustion chamber 12 of the pulse blade combustor 10a, a plurality of pipes 66 in parallel connection, these being uniformly spaced apart side-by-side and interconnecting a header 68 with a manifold 70. Connected to the manifold 70 is an outlet pipe 71.

Stated another way, in the compartment defined between the panels 52 and 58, the water conduit is shaped so as to require the water or other liquid to pass through the pipe portions 60 sequentially, whereas in the compartment defined between the panels 57 and 58, the water or other liquid passes in parallel between the header 68 and the manifold 70. This arrangement is particularly appropriate in view of the fact that the temperature in the combustion chamber 12 tends to be considerably higher than the average temperature in the exhaust portion 14 because of the radiant heat. The parallel configuration for the pipes 66 prevents over- heating by shortening the time during which the liquid is adjacent the hot conbustion chamber 12.

Attention is now directed to Figures 8-11, showing different views of a suitable diffuser arrangement for a typical cylindrical configuration (such as that shown in Figure 23). Cylinder intake tubes 72 with bell-shaped upper ends 74 (intake end) are located a distance p above a ring diffuser unit 76 with circular enlargements 78 aligned with respective tubes 72. The unit 76 is located at the leftward (intake) end of the combustor, i.e. left as pictured in Figures 23, 24 and 24a. It is pervious to the passage of gaseous materials, and has the effect of promoting good mixing. I have found that, when the distance p is maintained at or near a distance of .375", the sound level tends to be the lowest. By contrast, doubling the distance p to 0.75" tends to produce the loudest amplitude of sound level. Regardless of whether the distance is .375", 0.75" or a distance between these two, I have noted that the NOX tends to stay consistent over the entire range, while the CO varied approximately 50 ppm.

Attention is now directed to Figures 12-16, showing an apparatus for adjusting the distance between the diffuser and an intake. This apparatus includes a diffuser baffle 100 having a central portion 102 and two expanded end portions 104. The diffuser baffle 100 is supported at the lower end of a rotatable arm 106 having a handle 108. The arm 106 is supported by means not illustrated. The intake tubes are shown at 110, and it will be noted that these have bell-shaped upper portions 112 at their intake (upper) ends. It will further be noted that the diffuser is shown as being supported at a location where it is spaced below the bottom ends of the intake tubes 110.

Attention is particularly directed to Figure 13, which shows the provision of four blades 115 in an X configuration extending downwardly from the portions 104 of the diffuser 100, and in heat-transmitting contact therewith. The blades 115 function as a temperature enhancer, which tends to improve performance.

The blades 115 become hot during operation, and radiate heat into the combustor, thus enhancing carbon combustion.

Figures 17-19 show various views of an exhaust decoupler for the cylindrical embodiment. The decoupler shown in these figures includes a perforated cylinder 118 arranged to project transversely of the cylinder 120 at the exhaust end, lying along a diameter of the cylinder 120.

Figure 17 illustrates a water jacket 122 which surrounds the cylindrical end 124 of the unit.

An intake decoupler 125 is illustrated in Figures 20-22, again utilizing a pipe 126 extending diametrally and transversely with respect to the unit 128. In the case of the intake decoupler, it is contemplated to provide holes 129 in the top half only, as illustrated in Figure 21. Attention is now directed to Figures 23 and 24. As previously mentioned, Figure 23 shows a cylindrical embodiment of the blade, which can be imagined to result if the unit shown in Figure 1 were to be curled about a vertical axis so that the end walls 20 came into contact. However, the embodiment of Figure 23 differs somewhat from the configuration of Figure 1 by virtue of the fact that the inner wall 130 has no step, but rather is a perfect cylinder from one end to the other. In order to provide the greater wall separation in the combustion chamber end 132, the "offset" 133 of the outer wall, between the exhaust portion and the combustion chamber, is greater. This configuration is expected to decrease the cost of construction. In Figure 24, it is the outer wall 134 that is a true cylinder, and the step is provided in the inner wall 136, as shown at 138. The combustion chamber 132 of the embodiment shown in Figure 23 has an exhaust end 137 and fuel entry end 139.

Attention is now directed to Figures 25 and 26, which illustrate an axial sectional view across a modified "blade" combustor for establishing the maximum/optimum output/volume relationship. The modified combustor has two side walls 140, each defining a combustion portion 142 and an exhaust portion 144. Water jackets 146 are provided externally of the walls 140. A vertically movable header 148 defines the upper end of a combustion chamber 150. Between the exhaust portions 144 of the walls 140 are provided a plurality of internal, parallel, hollow baffles 152 which, together with the walls 140, define four parallel exhaust passageways 154. As the baffles 152 are hollow, they are ideal for containing a fluid, such as water, which can be heated by the exhaust gases. Means (not shown) are provided to duct water or other fluid into and out of the hollow baffles 152.

The Figure 26 embodiment is similar to that of Figure 25, except for the specific configuration of the upper ends of the baffles 152a. The two embodiments are being used to test the advantages and performance of specific angles. The remaining portions of the embodiment of Figure 26 are identified with the same numerals as the corresponding parts in Figure 25, but with the subscript a. The water jacket is not shown in Figure 26. In Figure 25 it will be noted that the baffles 152 have pointed upper ends 160, these being provided to allow smooth flow of the gases.

Figure 28 is similar to Figure 27, but shows the vertically movable, transverse header 148, through which a plurality of intake tubes 162 pass. Figure 29 and 30 show two patterns for the provision of the intake tubes, the two patterns having equivalent volumes.

While several embodiments of the improvements offered herein have been illustrated in the accompanying drawings and described hereinabove, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention, as set forth in the appended claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A pulsating combustor comprising: two parallel and substantially flat side wall panels (28, 30) separated to define opposed longer sides of an elongate combustion chamber (12) having an exhaust end and an entry end, two substantially flat end wall panels (20) spanning between the respective corresponding ends of the side wall panels (28, 30) and defining opposed shorter sides of said elongate combustion chamber (12), said chamber being substantially rectangular when seen in a transverse section taken perpendicular to all said panels, bottom wall means (33a) at said entry end of the combustion chamber (12), exhaust means (14) communicating with said exhaust end for ducting the products of combustion away from the combustion chamber (12), first means (32) for introducing a fuel mixture into the combustion chamber (12), and second means (33) for initiating pulsating combustion in the combustion chamber (12), characterized in that: insert means (34) are provided for occupying the four corner regions adjacent the end wall panels (20), and for presenting smoothly rounded surfaces partially delimiting the combustion chamber (12), thereby to counteract any tendency for the fuel mixture to become trapped in squared-off corners.

2. The invention claimed in claim 1, in which the insert means (34) is shaped to provide cylindrically rounded end portions for the combustion chamber (12).

3. The invention claimed in claim 1, in which said exhaust means (14) includes two substantially flat exhaust side panels (16, 18) spaced apart by a smaller distance than said side wall panels (28, 30) defining the combustion chamber, and two exhaust end panels (20) spanning between respective corresponding ends of the exhaust side panels (16, 18), further characterized in that: there is provided a liquid-heating conduit means (59) in heat-conductive contact with one of the exhaust side panels (16, 18) and the corresponding side wall panel (28, 30), the liquid heating conduit means having a boustrophedonic configuration (60) adjacent said one of the exhaust side panels (16, 18) and being divided into a plurality of one-pass pipes (66) adjacent said corresponding side wall panel (28, 30), the one-pass pipes being connected in parallel between a header (68) and a downstream collecting manifold (70).

4. A pulsating combustor comprising: two substantially cylindrical and substantially concentric side wall panels (130, 134, 136) defining between them a substantially cylindical combustion chamber (132, 132a) having an exhaust end (137) and an entry end (139), exhaust means (134, 136) communicating with said exhaust end (137) for ducting the products of combustion away from the combustion chamber (132, 132a), first means (72) for introducing a fuel mixture into the combustion chamber (132, 132a), and second means (33) for initiating pulsating combustion in the combustion chamber (132, 132a), characterized in that: said first means includes the provision of: a) a diffuser baffle (76) substantially coinciding with said entry end (139) and lying perpendicular to the axis of the cylidrical combustion chamber (132, 132a), and b) a plurality of substantially cylindrical intake tubes (72) perpendicular to said diffuser baffle (76) and each having a downstream end adjacent the diffuser baffle (76) and an upstream end remote from the diffuser baffle (76), the upstream end having a bell-like configuration (74), the downstream ends of the intake tubes (72) being spaced away from said diffuser baffle (76).

5. The pulsating combustor claimed in claim 4, in which the downstream ends of the intake tubes (72) are spaced substantially 0.375 inches away from the baffle (76).

6. The pulsating combustor claimed in claim 4, which further includes, for each intake tube (72), at least one blade (115) in the form of a flat, heat-conductive plate in heat-conductive contact with the diffuser baffle (76) and aligned with the respective tube (72), the blade extending in the direction remote from the respective tube (72).

7. The pulsating combustor claimed in claim 6, in which, for each tube (72), there are four blades (115) in a cross-formation, all blades lying in a plane parallel with the axis of the tube (72).

8. The pulsating combustor claimed in claim 4, in which the exhaust means includes inner and outer coaxial, cylindrical exhaust walls (134, 136) defining between them an annular exhaust passageway, the pulsating combustor further including a cylindrical water jacket surrounding at least the downstream portion of the outer cylindrical exhaust wall in heat-conductive contact therewith, and a perforated, cylindrical exhaust decoupler unit disposed at right-angles to the axis of the exhaust walls and projecting therethrough along a diameter thereof.

9. A pulsating combustor comprising: two parallel and substantially flat side wall panels (140, 140a) separated to define opposed longer sides of an elongate combustion chamber (142) having an exhaust end and an entry end, end wall means spanning corresponding ends of the side wall panels (140, 140a) and defining opposed shorter sides of the combustion chamber (142), bottom wall means (148, 148a) at an entry end of the combustion chamber (142), an exhaust portion (144) communicating with said combustion chamber (142) for ducting the products of combustion away from the combustion chamber (142), first means (32) for introducing a fuel mixture into the combustion chamber (142), and second means (33) for initiating pulsating combustion in the combustion chamber (142), characterized in that: said exhaust portion (144) is defined between two substantially flat, parallel walls, and includes a plurality of internal, parallel, spaced-apart hollow baffles (152) which define, between themselves and the parallel walls, a plurality of exhaust passageways (154).

10. The pulsating combustor claimed in claim 9, in which the baffles (152) are pointed in the direction contrary to the exhaust flow direction, and contain a liquid to be heated.

11. The pulsating combustor claimed in claim 9, in which the position of the bottom wall means between said panels (140, 140a) is adjustable toward and away from said baffles (152).