HEATING DEVICE, HEATING APPARATUS AND APPARATUS FOR PROVIDING A FLOW OF GASEOUS HYDROGEN

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from United Kingdom of Great Britain & Northern Ireland patent application number GB 2403594.1, filed on Mar. 13, 2024, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Technical Field

The invention relates to heating devices and apparatus, and to apparatus for providing a flow of gaseous hydrogen.

Description of Related Art

Heating a flow of liquid, supercritical or gaseous hydrogen to an appropriate temperature is generally a necessary step prior its use as a fuel by combustion within a hydrogen-burning gas turbine engine, or by oxidation within a fuel cell stack. In vehicle applications, particularly aerospace applications, minimising the size, weight and complexity of apparatus used for such heating is a key design concern. In a known apparatus, a small portion of an input flow of hydrogen is combusted and a heat-exchanger used to transfer heat from resulting combustion products to the remainder of the input flow of hydrogen in order to vaporise and/or heat it, however such apparatus has significant size and weight.

BRIEF SUMMARY

According to an example, a heating device for heating a flow of fluid has a device input and a device output and further comprises:

• • (i) a conduit for conducting a flow of fluid from the device input to the device output,
  • (ii) a hydrogen-burning torch arranged to heat the flow of fluid between the device input and the device output by flame-heating; and
  • (iii) an ignitor arranged to light the torch.

The conduit may be straight between the device input and the device output defining a fluid conduction direction with unit vector a, the hydrogen-burning torch being arranged to produce a flame extending from the hydrogen-burning torch in a direction with unit vector b, wherein 0<a.b<1.

The conduit may have a conduit wall, a first longitudinal portion of the conduit wall including the device input and a second longitudinal portion of the conduit wall being adjacent the first and mounting the hydrogen-burning torch, the second longitudinal portion having an internal transverse dimension with respect to a central longitudinal plane through the device greater than that of the first portion and the hydrogen-burning torch being arranged to produce a flame from a lateral position with respect to the plane, the lateral position being between lateral positions corresponding to the first and second dimensions.

The conduit wall may comprise a third longitudinal portion adjacent the second longitudinal portion and having an internal surface parallel to the unit vector b.

The first and second hydrogen-burning torches may each be disposed at a common longitudinal position between the device input and the device output and on a respective lateral side of a central longitudinal plane through the heating device.

The first and second hydrogen-burning torches may constitute a first pair of hydrogen-burning torches, the heating apparatus further comprising a second pair of hydrogen-burning torches, each pair of hydrogen-burning torches being disposed at a respective longitudinal position between the device input and the device output.

According to a second example, heating apparatus for heating a flow of fluid comprises an apparatus input, an apparatus output, a heating device according to the first example and supply means arranged to provide the or each hydrogen-burning torch of the heating device with a respective flow of hydrogen and a respective flow of oxygen, wherein the heating apparatus is arranged to provide an input flow of fluid which is applied to the apparatus input to the device input of the heating device and to provide a flow of heated fluid from the device output of the heating device to the apparatus output.

The heating apparatus may comprise an output line arranged to convey heated fluid from the device output of the heating device to the apparatus output and a vent line coupled to the output line, the heating apparatus being configurable to allow air to be vented from the heating apparatus via the vent line.

The supply means may be arranged to provide the or each hydrogen-burning torch of the heating device with a respective flow of hydrogen and a respective flow of oxygen in a stoichiometric or hydrogen-rich ratio.

The heating apparatus may be arranged to:

• • (i) provide a first portion of an input flow of hydrogen applied to the apparatus input to the device input of the heating device; and
  • (ii) provide a second portion of the input flow to the hydrogen-burning torch, or as the case may be, either
    • (a) provide a respective second portion (509A, 509B) of the input flow of hydrogen to each hydrogen-burning torch, or
    • (b) divide a second portion (409) of the input flow of hydrogen to provide each hydrogen-burning torch with a respective flow of hydrogen.

The heating apparatus may further comprise heating means arranged to heat the or each second portion of the input flow.

According to a third example, apparatus for delivering a flow of gaseous hydrogen comprises heating apparatus according to the second example and a heat-exchanger having a first fluid path from a first input to a first output and a second fluid path from a second input to a second output, the first and second fluid paths being in mutual thermal communication, the apparatus being arranged to receive an input flow of hydrogen at an input thereof and to provide first and second portions of the input flow to the apparatus input of the heating apparatus and to the first input of the heat-exchanger respectively, and wherein:

• • (i) the heating apparatus is arranged to provide a flow of hydrogen from the apparatus output thereof to the first input of the heat-exchanger;
  • (ii) the apparatus is arranged to provide hydrogen output from the first output of the heat-exchanger to an output of the apparatus; and
  • (iii) the apparatus is arranged to receive a flow of air at an air input thereof and provide at least a portion of the flow of air to the second input of the heat-exchanger, the heat-exchanger being arranged to output at least the portion of the flow of air at the second output of the heat-exchanger.

The apparatus may be arranged to provide a portion of a flow of air received at the air input to one or more hydrogen-burning torches of the heating device of the heating apparatus. According to a fourth example, apparatus for providing a flow of gaseous hydrogen comprises heating apparatus according to the second example and a heat-exchanger having a first fluid path from a first input to a first output and a second fluid path from a second input to a second output, the first and second fluid paths being in mutual thermal communication, the apparatus further comprising a closed water circuit including the first fluid path of the heat-exchanger, the heating apparatus and a water pump and in which circuit the first output of the heat exchanger is coupled to the apparatus input of the heating apparatus and the apparatus output of the heating apparatus is coupled to the first input of the heat-exchanger, the apparatus being arranged to receive an input flow of hydrogen at an input of the apparatus, convey the input flow to the second input of the heat-exchanger and convey an output flow of hydrogen from the second output of the heat-exchanger to an output of the apparatus.

The apparatus may be arranged to either:

• • (a) provide respective portions of an input flow of hydrogen received at the input of the apparatus to each hydrogen-burning torch of the heating device of the heating apparatus; or
  • (b) divide a portion of an input flow of hydrogen received at the input of the apparatus to provide each hydrogen-burning torch with a respective flow of hydrogen.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples are described below, with reference to the accompanying drawings in which:

FIGS. 1, 2 & 3 show longitudinal cross-sections of first, second and third example heating devices for heating a flow fluid;

FIGS. 4 & 5 show first and second example heating apparatus, each comprising the heating device of FIG. 1;

FIG. 6 shows a portion of a third example heating apparatus which comprises a fourth example heating device;

FIGS. 7 & 8 show first and second example apparatus for providing a flow of gaseous hydrogen, each comprising the heating apparatus of FIG. 4;

FIG. 9 shows a fourth example heating apparatus comprising the heating device of FIG. 1 and arranged to heat a flow of liquid water; and

FIG. 10 shows a third example apparatus for providing a flow of gaseous hydrogen, the apparatus comprising the heating apparatus of FIG. 9.

DETAILED DESCRIPTION

FIG. 1 shows a longitudinal cross-section of a first example heating device 100 for heating an input flow of fluid introduced at a device input 102 of the device 100 to produce an output flow of heated fluid at a device output 104 of the device 100. Example fluids are hydrogen (liquid, supercritical or gaseous) and liquid water. Heating in general may involve an increase in temperature only, a change of state from liquid to gas (whole or partial) only, or both a change of state and an increase in temperature. The device 100 comprises a conduit 109 having a conduit wall 110 which mounts a pair of hydrogen-burning torches 106A, 106B on respective lateral sides of central longitudinal plane 199 which bisects the heating device 100 into like lateral portions. Each hydrogen-burning torch 106A, 106B has a respective associated igniter 108A, 108B arranged to ignite a mixture of air (or oxygen) and hydrogen, which gases are supplied separately to the hydrogen-burning torches 106A, 106B from outside the heating device 100 during operation. Alternatively, a suitable mixture of air and hydrogen, or air and oxygen, may be provided as a single gaseous supply to the torches 106A, 106B. The igniters 108A, 108B may be conventional spark igniters. The transverse cross-section of the heating device 100 may be rectangular or circular for example; if circular then 199 represents a central longitudinal axis of the heating device 100 about which the heating device 100 has azimuthal symmetry, in addition to representing a central longitudinal plane through the heating device 100 which includes the central longitudinal axis.

In operation of the heating device 100, a flow of fluid introduced at the device input 102 flows in a general direction with a unit vector a substantially parallel to the plane 199 to the device output 104, the flow of fluid being heated between the device input 102 and the device output 104 by flames 107A, 107B produced by the hydrogen-burning torches 106A, 106B. The hydrogen-burning torch 107A is arranged to produce a flame 107A from a flame-emission point 105A in a direction with unit vector b such that the angle between a and b is acute, i.e. 0<a.b<1. Similarly, the hydrogen-burning torch 107B, which disposed on a lateral side of the plane 199 remote from the hydrogen-burning torch 107A, is arranged to produce a flame from a flame emission point 105B in a direction with unit vector c such that the angle between a and c is acute, i.e. 0<a.c<1. This geometry provides flame stability and reduces the risk that either flame 107A, 107B is extinguished by the flow of fluid within the conduit 109.

FIG. 2 shows a longitudinal cross-section of a second example heating device 200. Reference numerals in FIG. 2 differ by 100 from those labelling corresponding parts in FIG. 1. The heating device 200 has a conduit 209 having a conduit wall 210 and first 201, second 203 and third 213 contiguous longitudinal portions, the first 201 and third 213 portions including device input 202 and device output 204 respectively. The first portion 201 of the heating device 200 has an internal dimension x₁ with respect to central longitudinal plane 299. The second portion 203 has an internal dimension x₂ with respect to the plane 299 and mounts hydrogen-burning torches 206A, 206B and associated igniters 208A, 208B on respective lateral sides of the plane 299. Flame emission points 205A, 205B on the hydrogen-burning torches 206A, 206B are each located at a lateral position x₃ with respect to the plane 299, x₃ being intermediate the lateral positions x₁, x₂ corresponding to the internal dimensions x₁, x₂ of the heating device 100 at the first 210 and second 203 longitudinal portions respectively, i.e. x₁<x₃<x₂. This location of the flame emission points 205A, 205B provides further flame stability with respect to the flow of fluid within the conduit 209 during operation of the heating device 200 by shielding the flame emission points 205A, 205B from direct impingement by fluid within the conduit 209. The third longitudinal portion 213 of the heating device 200 is adjacent the second longitudinal portion 203 and has a sub-portion immediately adjacent the second longitudinal portion 213 at which the internal surface 211 of the conduit wall 210 is parallel to the directions b, c in which flames 207, 207B are produced by the hydrogen-burning torches 206A, 206B. The third longitudinal portion 213 therefore has a backwards-facing step; this assists flame stabilisation and facilitates ignition of the hydrogen-burning torches 206A, 206B.

FIG. 3 shows a third example heating device 300 having a conduit 309 and first 306A, 306B and second 306X, 306Y pairs of hydrogen-burning torches, each pair being disposed at a respective longitudinal position between an input 302 and an output 304 of the device 300. The torches of a given pair are located on respective lateral sides of central longitudinal plane 399 bisecting the device.

Referring to FIG. 4, a first example heating apparatus 400 for heating a flow of hydrogen (for example supercritical hydrogen derived from a tank of liquid hydrogen), comprises an apparatus input 412, an apparatus output 414, an air input 416, the heating device 100 of FIG. 1 (or, in variants, the heating device 200 of FIG. 2 or the heating device 300 of FIG. 3) and connecting gas conduction lines as shown. The heating apparatus 400 is arranged to receive an input flow of hydrogen at the apparatus input 412 and provide a first portion of the input flow to the device input 102 of the heating device 100. A second portion of the input flow of hydrogen passes to a heater 420 (which may be an electric heater) and a flow-control valve 422 and is then divided to provide each of the hydrogen-burning torches 106A, 106B of the heating device 100 with a respective flow of gaseous hydrogen. If liquid hydrogen is input to the heating apparatus 400, the heater 420 operates to at least vaporise the liquid hydrogen (and may also provide heating of the resulting gaseous hydrogen). In operation of the heating apparatus 400, a flow of air is input to the air input 416 and passes to a flow-control valve 424 after which it is divided and respective portions provided to the hydrogen-burning torches 106A, 106B of the heating device 100. A controller 426 provides control signals to the flow-control valves 422, 424 such that each hydrogen-burning torch receives a stoichiometric or hydrogen-rich combination of hydrogen and oxygen which is combusted to produce flames 107A, 107B which heat the first portion of the input flow of hydrogen to provide an output flow of heated hydrogen at the device output 104 of the heating device 100. The controller 426 and flow-control valves 422, 424 may provide the hydrogen-burning torches 106A, 106B with a stoichiometric combinations of hydrogen and oxygen, however preferably they are arranged to provide a hydrogen-rich combinations of hydrogen and oxygen in order to ensure than oxygen does not enter the flow of hydrogen within the heating device 100. The output flow of hydrogen at the device output 104 is provided to an apparatus output 414 via an output line which includes a valve 450 which is configurable such that air may be vented from the heating apparatus 400 via a vent line 418. The controller 426, heater 420, flow-control valves 422, 424 and associated gas conduction lines collectively operate as a supply means for supplying each of the hydrogen-burning torches 106A, 106B with a respective flow of hydrogen and a respective flow of oxygen.

The heating apparatus 400 may for example be used to heat gaseous a flow of gaseous hydrogen introduced at the apparatus input 412 to increase the temperature of the flow of gaseous hydrogen. Alternatively the apparatus 400 may be used to vaporise a flow of liquid hydrogen to provide a flow of gaseous hydrogen, typically (although not necessarily) increasing the temperature of the flow of hydrogen in addition to changing its state from liquid to gas. Alternatively, a flow of supercritical hydrogen may be input to the heating apparatus 400 in order to fully vaporise the flow, optionally also raising its temperature. The heating apparatus 400 may for example be comprised in a fuel system for delivering gaseous hydrogen at an appropriate temperature to combustion apparatus of hydrogen-burning gas turbine engine. A flow of hydrogen input to the heating apparatus may be derived from a tank storing liquid hydrogen. In a variant of the apparatus 400, pure oxygen is provided to an input equivalent to the air input 416 of the heating apparatus 400; however in mobile and transport applications, especially aeronautical applications, preferably air is utilised to combust hydrogen supplied to the hydrogen-burning torches, for example compressor bleed air from a gas turbine engine.

FIG. 5, in which reference numerals differ by 100 from those labelling corresponding parts in FIG. 4, shows a second example heating apparatus 500 in operation of which a first portion of an input flow of hydrogen applied at apparatus input 512 is provided to device input 102 of heating device 100 and a respective second portion 509A, 509B of the input flow is provided via a respective heater 520A, 520B and a respective control valve 522A, 522B to each hydrogen-burning torch 106A, 106B.

FIG. 6 shows a portion a third example heating apparatus which comprises a heating device similar to the heating device 100 of FIG. 1 and having first 606A, 606B and second 606X, 606Y pairs of hydrogen-burning torches, each pair being located at a respective longitudinal position along the device, providing additional control of an overall temperature rise provided by the device. A portion 609 of an input flow of hydrogen to the heating apparatus is applied to an electric heater 620 and then divided into four parts, each of which is individually controlled by a respective flow-control valve 622A, 622B, 622X, 622Y and input to a respective hydrogen-burning torch 606A, 606B, 606X, 606Y. Similarly, an air supply 616 is divided into four portions, each being controlled by a respective flow-control valve 624A, 624B, 624X, 624Y and each being provided to a respective hydrogen-burning torch 606A, 606B, 606X, 606Y. A controller (not shown) controls the flow-control valves 622, 624 such that each hydrogen-burning torch receives a stoichiometric mixture, or hydrogen-rich mixture, of hydrogen and oxygen.

FIG. 7 shows a first example apparatus 700 for providing a flow of gaseous hydrogen, the apparatus 700 comprising the heating apparatus 400 of FIG. 4. In operation of the delivery apparatus 600 an input flow of hydrogen, for example supercritical hydrogen derived from a tank of liquid hydrogen, is provided to an input 702. A flow-control valve 704 controls a flow of hydrogen to the apparatus input 412 of the heating apparatus 400. An air supply is provided at an air input 416 in order to supply the hydrogen-burning torches of the heating device comprised in the heating apparatus 400 with oxygen. Gaseous hydrogen is output from the heating apparatus 400 at the apparatus output 414 and may for example be provided at a suitable temperature (controlled by the heating apparatus 400) to combustion apparatus of a hydrogen-burning gas turbine engine, the apparatus 700 being comprised in a fuel system of an aircraft having propulsive hydrogen-burning gas turbine engines. Air input to the apparatus 700 at the air input 416 may be compressor bleed air from the gas turbine engine.

FIG. 8 shows a second example apparatus 800 for providing a flow of gaseous hydrogen, the delivery apparatus 800 having an input 802 and an output 894 and comprising a flow-control valve 804, the heating apparatus 400 of FIG. 4 and a heat-exchanger 850. The heat-exchanger 850 has a first fluid path between a first input 849A and a first output 849B, and a second fluid path between a second input 851A and a second output 851B, the first and second paths being in mutual thermal communication.

In operation of the delivery apparatus 800, a flow of hydrogen (for example supercritical hydrogen derived from a tank of liquid hydrogen) is input to the delivery apparatus 800 at the input 802 and divided by the flow-control valve 804 into first and second portions which are applied to the input 412 of the heating apparatus 400 and to the first input 849A of the heat-exchanger 850 respectively, both of which may provide heating. Hydrogen output from the apparatus output 414 of the heating apparatus 400 is also provided to the first input 849A of the heat-exchanger 850. A flow of air input at an air input 890 is divided into first and second portions which are provided to the heating apparatus 400 and to the second input of the heat-exchanger 850 respectively. Air is output from the second path of the heat-exchanger 850 at the second output 851B of the heat-exchanger 850. The proportion of the flow of hydrogen at the input 802 which is provided to the heating apparatus 400 may be varied by the flow-control valve 804 between 0% and 100% so that the overall amount of heating provided by the delivery apparatus 800 may be varied above a minimum amount of heating provided by the heat-exchanger 850 alone. The delivery apparatus 800 may be comprised in a fuel system for a hydrogen-burning gas turbine engine, with supercritical hydrogen derived from a tank storing liquid hydrogen being provided to the input 802 and gaseous hydrogen at a suitable temperature being delivered from the output 894 to combustion apparatus of the engine. Compressor bleed air from the gas turbine engine may be input to the air input 890.

FIG. 9, in which reference numerals differ by 500 from those labelling corresponding parts in FIG. 4, shows a fourth example heating apparatus 900 for heating a flow of water provided to an apparatus input 912. The heating apparatus 900 comprises the heating device 100 of FIG. 1. Hydrogen is supplied to hydrogen-burning torches 106A, 106B from a hydrogen input 909. Heated water is output at an apparatus output 914.

FIG. 10 shows a third example apparatus 1000 for providing a flow of gaseous hydrogen, which apparatus 1000 has an input 1002 and an output 1004 and comprises the heating apparatus 900 of FIG. 9, a heat-exchanger 1050, a flow-control valve 1004 and a water pump 1040. The heat-exchanger 1050 has first and second fluid paths in mutual thermal communication, the first fluid path having a first input 1049A and a first output 1049B and the second fluid path having a second input 1051A and a second output 1051B. A closed water circuit 1080 includes the heating apparatus 900, the heat-exchanger 1050 and the water pump 1040. The apparatus output 914 of the heating apparatus 900 is connected to the second input 1051A of the heat-exchanger 1050 via the water pump 1040, and the second output 1051B of the heat-exchanger 1050 is connected to the apparatus input 912 of the heating apparatus 900.

In operation of the apparatus 1000, a flow of hydrogen (for example supercritical hydrogen derived from a tank storing liquid hydrogen) provided to the input 1002 passes to the first input 1049A of the heat-exchanger 1050 via a flow-control valve 1004. The hydrogen is heated within the heat-exchanger 1050 and output at the first output 1049B of the heat-exchanger, and passes to the output 1094 of the delivery apparatus 1000. Water within the closed water circuit 1080 is heated by the heating apparatus 900 and loses heat when within the second path of the heat-exchanger 1050 to hydrogen within the first path. Hydrogen provided to the heating apparatus 900 at an input 909, and air (or oxygen) provided at an input 916 of the heating apparatus 900, are passed to the hydrogen-burning torches 106A, 106B of the heating device 100 comprised in the heating apparatus 900. The hydrogen provided at the input 909 may be a portion of the flow of hydrogen applied to the input 1002 of the apparatus 1000. The apparatus 1000 includes a bypass water line 913 and a valve 915 allowing water within the circuit 1080 to bypass the heating apparatus 900 in order to facilitate lighting of the hydrogen-burning torches within the heating apparatus 900 prior to input of a flow of hydrogen to the apparatus 1000 at the input 1002 thereof.

The apparatus 1000 may be comprised in a fuel system for a hydrogen-burning gas turbine engine, for example comprised in an aircraft, the apparatus 1000 being arranged to receive supercritical hydrogen from a tank of liquid hydrogen, and to vaporise and heat the hydrogen, and deliver resulting gaseous hydrogen to combustion apparatus of a hydrogen-burning gas turbine engine. Compressor bleed air from the gas turbine engine may be provided to air input 916.