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CN-121986209-A - Method for heating fuel in a turbine fuel supply system

CN121986209ACN 121986209 ACN121986209 ACN 121986209ACN-121986209-A

Abstract

A method of heating fuel of an automatic fuel supply system (19), the turbine comprising a heat pump (14), the heat pump comprising a closed circuit (20) in which a heat transfer fluid circulates, the circuit (20) comprising an evaporator (21) configured to exchange heat with oil of the turbine, a first condenser (22) configured to exchange heat with fuel, an expansion valve (23) configured to expand the heat transfer fluid before it enters the evaporator (21), and a compressor (24) configured to compress the heat transfer fluid before it enters the first condenser (22), the method comprising the steps of c) heating the fuel by operating the heat pump (14) according to a combined cycle in which the compressor (24) is driven at a determined rotational speed so as to supply excess power to the heat transfer fluid to heat the fuel.

Inventors

  • Fabian Irina Lhasa Tower
  • Fran ç ois Luc Michele. Rousseau
  • Mohammed Lamine butaleb

Assignees

  • 赛峰飞机发动机公司

Dates

Publication Date
20260505
Application Date
20241008
Priority Date
20231013

Claims (10)

  1. 1. A method of heating fuel for a fuel supply system (19) of a turbine (1), the turbine (1) comprising a heat pump (14), the heat pump comprising a closed circuit (20) in which a heat transfer fluid circulates, the circuit (20) comprising an evaporator (21) configured to exchange heat with oil of the turbine (1), a first condenser (22) configured to exchange heat with the fuel, an expansion valve (23) configured to expand the heat transfer fluid before it enters the evaporator (21), and a compressor (24) configured to compress the heat transfer fluid before it enters the first condenser (22), the method comprising the steps of: c) The fuel is heated by operating the heat pump (14) according to a combined cycle in which the compressor (24) is driven at a determined rotational speed so as to supply excess power to the heat transfer fluid configured to heat the fuel.
  2. 2. Method according to claim 1, characterized in that the determined rotational speed is greater than 50% of the maximum driving speed of the compressor (24), preferably greater than 60% of the maximum driving speed of the compressor (24), and more preferably greater than 70% of the maximum driving speed of the compressor (24).
  3. 3. Method according to any of the preceding claims, characterized in that it comprises, before step c), the following steps: a) Comparing the temperature of the fuel with a first reference temperature, the first reference temperature corresponding to a temperature below which the fuel may freeze; If the comparison in step a) indicates that the fuel temperature is below the first reference temperature, the fuel is heated in step c).
  4. 4. Method according to any of the preceding claims, characterized in that it comprises, before step c), the following steps: b) Comparing the temperature of the oil with a second reference temperature, the second reference temperature corresponding to the temperature of the oil at the end of preheating; if the comparison in step b) indicates that the oil temperature is higher than said second reference temperature, the fuel is heated in step c).
  5. 5. A turbine (1) configured to implement the method according to any one of the preceding claims, the turbine (1) comprising a heat pump (14) comprising a closed circuit (20) in which a heat transfer fluid circulates, the circuit (20) comprising an evaporator (21) configured to exchange heat with oil of the turbine (1), a first condenser (22) configured to exchange heat with fuel of the fuel supply system (19), an expansion valve (23) configured to expand the heat transfer fluid before entering the evaporator (21), and a compressor (24) configured to compress the heat transfer fluid before entering the first condenser (22).
  6. 6. Turbine (1) according to the preceding claim, wherein said compressor (24) is driven by an electric motor (26), said electric motor (26) being electrically controlled by a control device (27).
  7. 7. Turbine (1) according to claim 5 or 6, characterized in that said circuit (20) comprises a second condenser (28) mounted in parallel with said first condenser (22), said second condenser (28) being configured to exchange heat with a heat source (29) different from said fuel.
  8. 8. Turbine (1) according to the preceding claim, wherein the heat transfer fluid circulates in the first condenser (22) only when the heat pump (14) is operating according to the combined cycle.
  9. 9. Turbine (1) according to claim 7 or 8, wherein the heat source (29) is an air stream.
  10. 10. Turbine (1) according to any one of claims 7 to 9, wherein the first condenser (22) forms part of a first branch (30) of the circuit (20), the second condenser (28) forms part of a second branch (31) of the circuit (20), the circuit (20) comprising a common part (32) comprising at least the evaporator (21), an inlet of the branches (30, 31) being connected to an outlet of the common part (32) via a three-way valve (33).

Description

Method for heating fuel in a turbine fuel supply system Technical Field The present invention relates to a method of heating fuel for a fuel supply system for supplying a turbine, and a turbine configured to implement the method. Background A dual flow turbine typically includes a fan driven by a power turbine and a gas generator that generates gas for driving the power turbine. The gas generator includes at least one compressor, a combustor, and at least one turbine. The fan generates an air flow that is divided into a primary flow configured to supply the gas generator and a secondary flow that contributes primarily to the thrust provided by the turbine. The turbine also comprises various oil circuits whose function is, for example, to lubricate the movable elements of the turbine (bearings, gears, etc.). In order for the oil to fully perform its function, it is critical that its temperature be maintained within a given range, in particular using a cooling system. Engine manufacturers are currently facing a significant challenge. In fact, the new turbine architecture incorporates more oil circuits, mainly due to the inclusion of a speed reducer (between the power turbine and the fan) and/or the increased use of a generator to enhance the mixing properties of the turbine. These additional oil circuits inevitably mean an increase in the thermal power to be dissipated, and therefore obligation to check the existing cooling systems. To meet this need, it is known from document FR2993610A1 in the name of the applicant to cool the oil with a heat pump. Heat pumps of this type comprise a closed circuit in which a heat transfer fluid circulates, which circuit comprises in particular an evaporator, a condenser, a compressor and an expansion valve. More specifically, the evaporator evaporates the heat transfer fluid by extracting heat from the oil (heat source). The condenser condenses the heat transfer fluid, evacuating the heat into an air stream (cold source). The compressor compresses the heat transfer fluid (gaseous) to increase its pressure, and then passes through the condenser. The expansion valve expands the heat transfer fluid (liquid) to reduce its pressure and then passes through the evaporator. In the above documents, the heat pump is used only for cooling oil. However, engine manufacturers note that it may be advantageous to use the heat pump for other functions, particularly fuel heating. Heating of the fuel is necessary when the temperature of the fuel falls below a critical temperature below which the fuel is susceptible to icing. In particular, when the turbine has been stationary for a long time and the external conditions are cold, it may be necessary to heat the fuel to start the turbine. Typically, to meet this need, turbines include a separate system dedicated to heating the fuel, which in particular includes a fuel/oil heat exchanger. More specifically, once the oil is heated, the thermal power of the oil is used to heat the fuel via a heat exchanger. Engine manufacturers also note that the compressor of the heat pump is sized to cope with the worst case, i.e. a situation where the oil has a large thermal power to dissipate (e.g. high operating speed in combination with high external temperature), and the air flow (cold source) has a high temperature. In practice, however, the compressor is sometimes operated at maximum capacity only. Thus, engine manufacturers point out that it may be advantageous to use the capacity of the compressor for other purposes, particularly fuel heating. It is therefore an object of the present invention to optimize a heat pump so that the heat pump can not only cool oil but also heat fuel. Disclosure of Invention The present invention therefore proposes a method of heating fuel for a fuel supply system for supplying a turbine, the turbine comprising a heat pump, the heat pump comprising a closed circuit in which a heat transfer fluid circulates, the circuit comprising an evaporator configured to exchange heat with oil of the turbine, a first condenser configured to exchange heat with fuel, an expansion valve configured to expand the heat transfer fluid before it enters the evaporator, and a compressor configured to compress the heat transfer fluid before it enters the first condenser, the method comprising the steps of: c) The fuel is heated by operating the heat pump according to a combined cycle in which the compressor is driven at a determined rotational speed to supply excess power to the heat transfer fluid configured to heat the fuel. This method allows the use of a heat pump to heat the fuel. This cycle is referred to as a "combined cycle" because it combines both an oil cooling function and an oil heating function. When the heat pump is operating in a combined cycle, the compressor provides excess/extra power to the heat transfer fluid for heating the fuel. The thermal power extracted from the oil is obviously added to the excess power provided by the com