FIELD OF INVENTION

[001] This invention relates to polymer electrolyte fuel cells, and more particularly but not exclusively to flow field and manifold for supplying fluids in fuel cells.

BACKGROUND OF INVENTION

[002] Fuel cells are electrochemical converters that convert chemical energy of fuel into electricity. One of the types of fuel cells is Polymer Electrolyte Fuel Cell (PEFC) in which polymer membrane is used as electrolyte. The PEFC includes a

Membrane Electrode Assembly (MEA) layer. The MEA comprises a polymer electrolyte with electrodes on both sides of the membrane. Further, on either sides of the MEA, porous and electronic conducting medium called Gas Diffusion Layer (GDL) are used.

The GDL act as electron collectors and also provide the passage for the reactant gases to reach the electrodes. The reactant gases are distributed on the electrode surfaces (anode and cathode) through the channels which are nonporous current collectors called flow field plates.

[003] Generally, fuel cells are connected in series using bipolar plates which are used as inter connector between two adjacent cells. The non porous current collectors of single cell are used as bipolar plate for stacking the cells. The electrode reaction involved in the fuel cells operations is mainly exothermic, which require the removal of the produced heat. Generally, coolant is used to maintain the operating temperature at constant level. In this purpose the coolant channels are incorporated on the bipolar plate as well. A series of fuel cells are stacked between a pair of end plate immediately adjacent to the outermost bipolar plate or flow field plate.

[004] In polymer electrolyte fuel cells, hydrogen is oxidized on the anode side in the presence of platinum catalyst, and hydrogen ion and electron are produced. The polymer electrolyte allows hydrogen ions to flow through it and the electrons flow through the external circuit and produce external work. On the cathode side, oxygen is reduced in presence of catalyst, and produces water. In this way, the oxidation tendency of hydrogen is used to convert the chemical energy into electrical energy in the fuel cells.

[005] It is desirable to have homogenous performance across the whole electrode area of the fuel cell. The local performance inside the fuel cells is influenced by various parameters such as local temperature, water distribution, and partial pressure of the reactant gases. Additionally, for optimum performance, the reactant gases must be supplied on both sides of the electrode in appropriate proportions. The heterogeneous activities of the reactant gases on the electrodes of the fuel cells cause poor performance. Moreover, the heterogeneous activity is one of the important reasons for lessening the durability of fuel cells. The reactant and coolant flow field design influences the performance of the fuel cell by controlling the temperature, pressure and water distribution inside the fuel cell.

[006] Traditional flow field design and reactant gas supply system enable any one of, counter flow field, multi-channel serpentine, interdigitated, and dead end. Each of the aforementioned types of flow field designs has their own advantages and disadvantages. However, none of the existing systems teach a technique to choose from at least all the above mentioned types of flow based on requirement. STATEMENT OF INVENTION

[007] Accordingly the invention provides system for achieving desired flow pattern in a fuel cell is provided. The system includes a pair of fuel manifold configured to facilitate flow of fuel, wherein the pair of fuel manifolds comprises a first group of fuel manifolds and a second group of fuel manifolds. Further, a first set of channels defined on a bipolar plate and a second set of channels defined on the bipolar plate. The said first group of fuel manifolds is in fluid connection with the said first set of channels and the said second group of fuel manifolds is in fluid connection with the said second set of channels.

[008] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing . from the spirit thereof, and the embodiments herein include all such modifications. BRIEF DESCRIPTION OF FIGURES

[009] This invention is illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0010] FIG. 1 illustrates an exploded view of a stack of fuel cells, in accordance with an embodiment;

[0011] FIG. 2 illustrates a bipolar plate 108, in accordance with an embodiment;

[0012] FIG. 3 illustrates the bipolar plate 108, in accordance with an embodiment;

[0013] FIG. 4 illustrates valves that are configured with a pair of fuel manifolds 110a to 1 lOd to regulate flow of fuel through channels that are provided to accommodate flow of fuel, in accordance with an embodiment;

[0014] FIG. 5 illustrates the flow of fuel in counter flow forward pattern, in accordance with an embodiment;

[0015] FIG. 6 illustrates the flow of fuel in counter flow backward pattern, in accordance with an embodiment;

[0016] FIG. 7 illustrates the flow of fuel in serpentine flow forward pattern, in accordance with an embodiment;

[0017] FIG. 8 illustrates the flow of fuel in serpentine flow backward pattern, in accordance with an embodiment;

[0018] FIG, 9 illustrates the flow of fuel in interdigitated flow pattern in forward direction, in accordance with an embodiment;

[0019] FIG. 10 illustrates the flow of fuel in interdigitated flow pattern in forward direction, in accordance with an embodiment;

[0020] FIG. 11 illustrates the flow of fuel in interdigitated flow pattern in backward direction, in accordance with an embodiment; [0021] FIG. 12 illustrates the flow of fuel in interdigitated flow pattern in backward direction, in accordance with an embodiment;

[0022] FIG. 13 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment;

[0023] FIG. 14 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment;

[0024] FIG. 15 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment; and

[0025] FIG. 16 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment.

DETAILED DESCRIPTION OF INVENTION

[0026] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0027] The embodiments herein provide a system and method for achieving desired flow pattern in a fuel cell. Referring now to the drawings, and more particularly to FIGS. 1 through 16, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0028] FIG. 1 illustrates an exploded view of a stack of fuel cells, in accordance with an embodiment. Each fuel cell includes a Membrane Electrode Assembly (MEA) 102. Further, on either side of the MEA 102, gaskets 104 are provided. Additionally, on either side of the MEA 102, bipolar plates 106 and 108 are provided. The fuel cells are connected in series using bipolar plates, which are used as interconnector between two adjacent cells. The MEA 102 includes a polymer electrolyte with electrodes on both sides of the membrane. On one side of the MEA 102 anode is provided and cathode is provided on the other side of the electrode. Further, on either side of the MEA 102 porous and conducting medium called Gas Diffusion Layer (GDL) are provided. The GDL act as electron collector and also provide passage for reactant gases to reach the electrodes. The reactant gases are distributed on the anode and cathode through channels provided on bipolar plates 108 and 106, respectively. The reactant gases are supplied to the bipolar plates using respective fluid supply manifolds.

[0029] In an embodiment, the stack of fuel cells has a pair of fluid supply manifolds 110a to HOd, 112a to 112d, and 114a to 114d. In an embodiment, pair of fuel manifold 110a to HOd facilitates flow of fuel, for example hydrogen; pair of coolant manifold 112a to 112d facilitates flow of coolant, for example, water; and pair of fuel manifold 114a to 114d facilitates flow of oxidant, for example air.

[0030] The fuel manifolds 110a to HOd are connected to channels provided on bipolar plates that facilitate supply of fuel (hydrogen) to the anode. In an embodiment, the bipolar plates that are provided on the anode side will have channels provided on the side facing the anode for receiving fuel (hydrogen), and the side of the bipolar place facing away from the anode will have channels for receiving the coolant. Similarly, the bipolar plates that are provided on the cathode side will have channels provided on the side facing the cathode for receiving oxidant (air), and the side of the bipolar place facing away from the cathode will have channels for receiving the coolant. In light of the purpose of the channels provided on the bipolar plates, respective manifolds will be fluidly connects to the channels.

[0031] FIG. 2 illustrates a bipolar plate 108, in accordance with an embodiment.

The bipolar plate illustrated in the figure is provided on the anode side of the MEA 102. Further, the side 204 of the bipolar plate 108 illustrated in the instant figure is the side facing the anode. The surface of the bipolar plate 108 defines a first set of channels 202a and a second set of channels 202b to accommodate fuel supplied by a pair of fuel manifolds 110a to l lOd. A first set of channels 202a is in fluid connection with a first group of fuel manifolds 110a and l lOd of the pair of fuel manifolds and a second set of channels 202b is in fluid connection (connection not illustrated) with a second group of fuel manifolds 110b and 110c of the pair of fuel manifolds.

[0032] FIG. 3 illustrates the bipolar plate 108, in accordance with an embodiment. The bipolar plate 108 illustrated in the figure is provided on the anode side of the ME A 102. Further, the side 206 of the bipolar plate illustrated in the instant figure is the side facing away from the anode. The surface of the bipolar plate defines channels to accommodate coolant supplied by coolant manifolds. The channel is in fluid connection with coolant manifolds 112b and 112c.

[0033] Similarly, in accordance with an embodiment, a bipolar plate 106 provided on the cathode side of the MEA 102 will have channels defined on its surface facing the cathode, wherein the channels accommodate oxidants supplied by a pair of oxidant manifolds 114a to 114d. A first set of channels is in fluid connection with oxidant manifolds with a first group of oxidant manifolds 114a and 114d of the pair of oxidant manifolds, and a second set of channels 202b is in fluid connection with a second group of oxidant manifolds 114b and 114c of the pair of oxidant manifolds. Further, the side of the bipolar plate facing away from the cathode has channel defined on its surface channels to accommodate coolant supplied by coolant manifolds. The channel is in fluid connection with coolant manifolds.

[0034] The manifolds are provided with valves to achieve desired flow through the channels to which they are fluidly connected. FIG. 4 illustrates valves that are configured with a pair of fuel manifolds 110a to l lOd to regulate flow of fuel through channels that are provided to accommodate flow of fuel.

[0035] The figure illustrates a pair of fuel manifolds, a first group of fuel manifold 110a and l lOd are fluidly connected through a first set of channels 202a provided on the bipolar plate 108, and a second group of fuel manifold 110b and 110c are . fluidly connected through a second set of channels 202b provided on the bipolar plate 108. Further, desired flow is achieved through the first 202a and second 202b set of channels by operating the valves that are configured with the fuel manifolds 112a to 112d.

[0036] In an embodiment, eight valves are configured with fuel manifolds to achieve desired flow through the channels 202a and 202b provided on the bipolar plates 108 by opening some valves while other valves are kept closed.

[0037] In accordance with an embodiment, fuel is supplied through a pair of fuel manifolds 110a to 1 lOd. The pair of fuel manifolds 110a to 1 lOd includes a first group of fuel manifolds 110a and 1 lOd and a second group of fuel manifolds 110b and 110c. The first group of fuel manifolds 110a and l lOd includes two manifolds that are in fluid connection through first set of fuel channels 202a defined on the surface 204 of the bipolar plates 108. The two manifolds are provided at the ends of the first set of fuel channels 202a. Similarly, the second group of fuel manifolds 110b and 110c includes two manifolds that are in fluid connection through second set of fuel channels 202b defined on the surface 204 of the bipolar plates 108. The two manifolds are provided at the ends of the second set of fuel channels 202b. [0038] The valves configured with the pair of fuel manifolds can be operated to establish connection between any of fuel inlet 402 and fuel outlet 404 with the pair of manifolds.

[0039] In an embodiment, as illustrated in FIG. 4 eight valves are configured with the pair of fuel manifolds. A first valve "B" is provided between the first manifold 110a of the first group of manifolds and the fuel inlet 402, a second valve "G" is provided between the first manifold 110a of the first group of manifolds and the fuel outlet 404, a third valve "E" is provided between the second manifold l lOd of the first group of manifolds and the fuel inlet 402, a fourth valve "C" is provided between the second manifold 1 lOd of the first group of manifolds and the fuel outlet 404, a fifth valve "H" is provided between the first manifold 110b of the second group of manifolds and the fuel inlet 402, a sixth valve "D" is provided between the first manifold 110b of the second group of manifolds and the fuel outlet 404, a seventh valve "A" is provided between the second 110c manifold of the second group of manifolds and the fuel inlet 402, and a eight valve "F" is provided between the second manifold 110c of the second group of manifolds and the fuel outlet 404.

[0040] Table 1 provides the status at which each of the eight valves has to be maintained to achieve a desired flow pattern.

Sr.

No. Operating mode A B C D E F G H

0 Totally closed: 0 0 0 0 0 0 0 0

shutdown

1 Counter forward 1 1 1 1 0 0 0 0 flow backwa 0 0 0 0 1 1 1 1 rd

Serpenti forward 0 1 1 0 0 1 0 1 ne (total)

backwa 1 0 0 1 1 0 1 0 rd

(total)

Inter- forward 0 1 0 0 0 1 0 0 digitated 1

forward 0 0 1 0 0 0 0 1

2

backwa 1 0 0 0 0 0 1 0 rdl

backwa 0 0 0 1 1 0 0 0 rd2

Dead end Dead 1 1 0 0 0 0 0 0

End 1

Dead 0 1 0 0 0 0 0 1

End 2

Dead 1 0 0 0 1 0 0 0

End 3

Dead 0 0 0 0 1 0 0 1

End 4 [0041] In the above table, the status at which each of the valves is maintained is indicated by either "1" or "0". "1" is used to indicate the valve being maintained in open position, and "0" is used to indicate the valve being maintained in closed position.

[0042] In an embodiment, a counter flow pattern in forward direction is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 5 illustrates the flow of fuel in counter flow forward pattern, in accordance with an embodiment. To enable flow of fuel in the counter flow forward pattern the first valve B, fourth valve C, sixth valve D and seventh valve A, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110a of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the inlet 402. Further, the second manifold l lOd of the first group of manifolds and the first manifold 110b of the second group of manifolds are connected to the outlet 404.

[0043] With the status of the valves being maintained in a manner illustrated in

FIG. 5, fuel flow in counter flow forward pattern is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110a of the first group of manifolds and second manifold 110c of the second group of manifolds. The fuel from the fuel inlet 402 passes through the first valve that is kept open and reaches the first set of channels 202a. The fuel circulates through the first set of channels and reaches the end of the first set of channels to which the second manifold l lOd of the first group of manifolds is connected. The fuel later passes through the fourth valve that is kept open and reaches the fuel outlet 404. Similarly, the fuel from the fuel inlet 402 passes through the seventh valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the first manifold 110b of the second group of manifolds is connected. The fuel later passes through the sixth valve that is kept open and reaches the fuel outlet 404. It may be noted that by establishing the flow of fuel in a pattern as described above, the fuel flow in the first set and second set of channels 202b is in opposite direction.

[0044] In an embodiment, a counter flow pattern in backward direction is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 6 illustrates the flow of fuel in counter flow backward pattern, in accordance with an embodiment. To enable flow of fuel in the counter flow backward pattern the third valve E, eighth valve F, second valve G and fifth valve H, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110b of the second group of manifolds and the second manifold HOd of the first group of manifolds are connected to the inlet 402. Further, the first manifold 110a of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the outlet 404.

[0045] With the status of the valves being maintained in a manner illustrated in FIG. 6, fuel flow in counter flow forward pattern is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110b of the second group of manifolds and second manifold HOd of the first group of manifolds. The fuel . from the fuel inlet 402 passes through the fifth valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the second manifold 110c of the second group of manifolds is connected. The fuel later passes through the eighth valve that is kept open and reaches the fuel outlet 404. Similarly, the fuel from the fuel inlet 402 passes through the third valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202ato which the first manifold 110a of the first group of manifolds is connected. The fuel later passes through the second manifold that is kept open and reaches the fuel outlet 404. It may be noted that by establishing the flow of fuel in a pattern as described above, the fuel flow in the first set and second set of channels 202b is in opposite direction.

[0046] In an embodiment, a serpentine flow pattern in forward direction is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 7 illustrates the flow of fuel in serpentine flow forward pattern, in accordance with an embodiment. To enable flow of fuel in the serpentine flow forward pattern the first valve B, fourth valve C, eighth valve F and fifth valve H, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110a of the first group of manifolds and the first manifold 110b of the second group of manifolds are connected to the inlet 402. Further, the second manifold 1 lOd of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the outlet 404.

[0047] With the status of the valves being maintained in a manner illustrated in FIG. 7, fuel flow in serpentine pattern in forward direction is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110a of the first group of manifolds and first manifold 110b of the second group of manifolds. The fuel from the fuel inlet 402 passes through the first valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the second manifold l lOd of the first group of manifolds is connected. The fuel later passes through the fourth valve that is kept open and reaches the fuel outlet 404. Similarly, the fuel from the fuel inlet 402 passes through the fifth valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the second manifold 110c of the second group of manifolds is connected. The fuel later passes through the fourth valve that is kept open and reaches the fuel outlet 404. It may be noted that by establishing the flow of fuel in a pattern as described above, the fuel flow in the first set and second set of channels 202b is in the same direction.

[0048] In an embodiment, a serpentine flow pattern in backward direction is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 8 illustrates the flow of fuel in serpentine flow backward pattern, in accordance with an embodiment. To enable flow of fuel in the serpentine flow backward pattern the seventh valve A, sixth valve D, third valve E and second valve G, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the second manifold l lOd of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the inlet 402. Further, the first manifold 110a of the first group of manifolds and the first manifold 110b of the second group of manifolds are connected to the outlet 404.

[0049] With the status of the valves being maintained in a manner illustrated in FIG. 8, fuel flow in serpentine pattern in backward direction is established. The fuel from the fuel inlet 402 is supplied to the second manifold 1 lOd of the first group of manifolds and second manifold 110c of the second group of manifolds. The fuel from the fuel inlet 402 passes through the third valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the first manifold 110a of the first group of manifolds is connected. The fuel later passes through the second valve that is kept open and reaches the fuel outlet 404. Similarly, the fuel from the fuel inlet 402 passes through the seventh valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the first manifold 110b of the second group of manifolds is connected. The fuel later passes through the sixth valve that is kept open and reaches the fuel outlet 404. It may be noted that by establishing the flow of fuel in a pattern as described above, the fuel flow in the first set and second set of channels 202b is in the same direction.

[0050] In an embodiment, an interdigitated flow pattern in forward direction (1) is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 9 illustrates the flow of fuel in interdigitated flow pattern in forward direction, in accordance with an embodiment. To enable flow of fuel in the interdigitated flow pattern in forward direction the first valve "B" and eight valve "F\ are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110a of the first group of manifolds is connected to the inlet 402. Further, second manifold 110c of the second group of manifolds is connected to the outlet 404.

[0051] With the status of the valves being maintained in a manner illustrated in FIG. 9, fuel flow in interdigitated pattern in forward direction is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110a of the first group of manifolds. The fuel from the fuel inlet 402 passes through the first valve "B" that is kept open and reaches the first set of channels. The fuel later passes through second manifold 110c of the second group of manifolds and reaches the fuel outlet 404 via eight valve "F" that is kept open.

[0052] In an embodiment, an interdigitated flow pattern in forward direction

(2) is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 10 illustrates the flow of fuel in interdigitated flow pattern in forward direction, in accordance with an embodiment. To enable flow of fuel in the interdigitated flow pattern in forward direction the fifth valve "H" and fourth valve "C", are left open, while all other valves remain closed. By maintaining the valves in the above described position, first manifold 110b of the second group of manifolds is connected to the inlet 402. Further, second manifold HOd of the first group of manifolds is connected to the outlet 404.

[0053] With the status of the valves being maintained in a manner illustrated in FIG. 10, fuel flow in interdigitated pattern in forward direction is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110b of the second group of manifolds. The fuel from the fuel inlet 402 passes through the fifth valve "H" that is kept open and reaches the second set of channels. The fuel later passes through second manifold HOd of the first group of manifolds and reaches the fuel outlet 404 via fourth valve "C" that is kept open.

[0054] In an embodiment, an interdigitated flow pattern in backward direction (1) is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 11 illustrates the flow of fuel in interdigitated flow pattern in backward direction, in accordance with an embodiment. To enable flow of fuel in the interdigitated flow pattern in backward direction the second valve "G" and seventh valve "A", are left open, while all other valves remain closed. By maintaining the valves in the above described position, second manifold 110c of the second group of manifolds is connected to the inlet 402. Further, first manifold 110a of the first group of manifolds is connected to the outlet 404.

[0055] With the status of the valves being maintained in a manner illustrated in FIG. 11, fuel flow in interdigitated pattern in backward direction is established. The fuel from the fuel inlet 402 is supplied to the second manifold 110c of the second group of manifolds. The fuel from the fuel inlet 402 passes through the seventh valve "A" that is kept open and reaches the second set of channels. The fuel later passes through first manifold 110a of the first group of manifolds and reaches the fuel outlet 404 via second valve "G" that is kept open.

[0056] In an embodiment, an interdigitated flow pattern in backward direction (2) is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 12 illustrates the flow of fuel in interdigitated flow pattern in backward direction, in accordance with an embodiment. To enable flow of fuel in the interdigitated flow pattern in backward direction a third valve "E" and sixth valve "D", are left open, while all other valves remain closed. By maintaining the valves in the above described position, second manifold l lOd of the first group of manifolds is connected to the inlet 402. Further, first manifold 110b of the second group of manifolds is connected to the outlet 404.

[0057] With the status of the valves being maintained in a manner illustrated in FIG. 12, fuel flow in interdigitated pattern in backward direction is established. The fuel from the fuel inlet 402 is supplied to the second manifold l lOd of the first group of manifolds. The fuel from the fuel inlet 402 passes through a third valve "E" that is kept open and reaches the first set of channels. The fuel later passes through first manifold 110b of the second group of manifolds and reaches the fuel outlet 404 via sixth valve "D" that is kept open.

[0058] In an embodiment, a dead end flow pattern is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 13 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment. To enable flow of fuel in the dead end flow pattern the seventh valve A and first valve B, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110a of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the inlet 402. Further, none of the manifolds are connected to the outlet.

[0059] With the status of the valves being maintained in a manner illustrated in FIG. 13, fuel flow in dead end pattern is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110a of the first group of manifolds and second manifold 110c of the second group of manifolds. The fuel from the fuel inlet 402 passes through the first valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the second manifold HOd of the first group of manifolds is connected. Similarly, the fuel from the fuel inlet 402 passes through the seventh valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the first manifold 110b of the second group of manifolds is connected. [0060] In an embodiment, a dead end flow pattern is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 14 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment. To enable flow of fuel in the dead end flow pattern the first valve B and fifth valve H, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the first manifold 110a of the first group of manifolds and the first manifold 110b of the second group of manifolds are connected to the inlet 402. Further, none of the manifolds are connected to the outlet 404.

[0061] With the status of the valves being maintained in a manner illustrated in FIG. 14, fuel flow in dead end pattern is established. The fuel from the fuel inlet 402 is supplied to the first manifold 110a of the first group of manifolds and first manifold 110b of the second group of manifolds. The fuel from the fuel inlet 402 passes through the first valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the second manifold l lOd of the first group of manifolds is connected. Similarly, the fuel from the fuel inlet 402 passes through the fifth valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the second manifold 110c of the second group of manifolds is connected.

[0062] In an embodiment, a dead end flow pattern is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 15 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment. To enable flow of fuel in the dead end flow pattern the seventh valve A and third valve E, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the second manifold l lOd of the first group of manifolds and the second manifold 110c of the second group of manifolds are connected to the inlet 402. Further, none of the manifolds are connected to the outlet 404.

[0063] With the status of the valves being maintained in a manner illustrated in

FIG. 15, fuel flow in dead end pattern is established. The fuel from the fuel inlet 402 is supplied to the second manifold 1 lOd of the first group of manifolds and second manifold 110c of the second group of manifolds. The fuel from the fuel inlet 402 passes through the third valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the first manifold 110a of the first group of manifolds is connected. Similarly, the fuel from the fuel inlet 402 passes through the seventh valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the first manifold 110b of the second group of manifolds is connected.

[0064] In an embodiment, a dead end flow pattern is achieved by maintaining the status of the valves as indicated in Table 1. Further, FIG. 16 illustrates the flow of fuel in dead end flow pattern, in accordance with an embodiment. To enable flow of fuel in the dead end flow pattern the third valve E and fifth valve H, are left open, while all other valves remain closed. By maintaining the valves in the above described position, the second manifold l lOd of the first group of manifolds and the first manifold 110b of the second group of manifolds are connected to the inlet 402. Further, none of the manifolds are connected to the outlet 404. [0065] With the status of the valves being maintained in a manner illustrated in FIG. 16, fuel flow in dead end pattern is established. The fuel from the fuel inlet 402 is supplied to the second manifold l lOd of the first group of manifolds and first manifold 110b of the second group of manifolds. The fuel from the fuel inlet 402 passes through the third valve that is kept open and reaches the first set of channels. The fuel circulates through the first set of channels 202a and reaches the end of the first set of channels 202a to which the first manifold 110a of the first group of manifolds is connected. Similarly, the fuel from the fuel inlet 402 passes through the fifth valve that is kept open and reaches the second set of channels 202b. The fuel circulates through the second set of channels 202b and reaches the end of the second set of channels 202b to which the second manifold 110c of the second group of manifolds is connected.

[0066] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.