RU2165375C1 - Method of operation of shipboard power plant - Google Patents

Abstract

FIELD: power-plant engineering; operation of gas-and-hydro-jet propulsors; generation of power; operation of devices pumping-out water in an emergency. SUBSTANCE: method consists in delivery of sea water and combustible gas to working cylinder which is profiled in shape terminating in nozzle. Water is admitted to working cylinder when it is filled with rarefied gas-and-water mixture. Water moves towards nozzle (towards lower pressure) freeing space behind it in working cylinder and combustion gas is admitted to this space where it expands simultaneously compressing and expelling the previous gas-and-water mixture through nozzle, thus creating the reactive thrust. Then, combustible gas is mixed with remaining sea water forming the gas-and-water mixture which creates rarefaction in cooling, thus admitting sea water and hot gas into working cylinder. Gas may be adiabatically expanded in power turbine. Sea water and hot gas may be admitted to cylinder in turn through revolving spool valve. Sea water may be admitted to working cylinder through hydraulic pulsator entrapping the hot gas. EFFECT: enhanced efficiency of shipboard power plant. 5 cl, 1 dwg

Description

 The invention relates to power engineering and can be used to drive river and sea vessels, generate electricity, and in emergency cases for pumping sea water from the hull.

 Known gas-jet propulsion (Muslin E. Machines of the 20th century.- M .: Mashinostroenie, 1971, p. 206), which is a conventional turbojet engine with a gas turbine, the jet stream of which is sent through a specially profiled channel under the bottom of the vessel. Mixing with water, a gas jet carries away the emulsion formed and throws it back, forming a jet thrust.

 The disadvantage of this jet engine is the low effective efficiency of about 10-14% (since the efficiency of the propulsion device is approximately 0.5, and the efficiency of the turbojet engine-gas turbine engine without regeneration is 20-28% (see AM Tskovich Fundamentals of Heat Engineering.- M. : Higher School, 1975, p. 321), i.e., the effective efficiency will be equal to (20-28%) · 0.5 = 10-14%.

 A steam-gas installation of an underwater vehicle is known (Alekseev G.N. General heat engineering.- M .: Higher school, 1980, p. 353, 471), in which a mixture of kerosene with air burns in a gas-vapor boiler at a pressure of 25-30 bar, and into the zone behind the flame front, water is supplied through special nozzle tubes. The resulting gas comes through a spool distribution into a double-acting piston expansion machine that rotates the propeller.

 The disadvantage of this installation is the low effective efficiency of about 10-15% (ibid., P. 471), since the bulk of the energy of the hot gas is used to convert water to steam. In addition, due to the high pressure and temperature of the combined-cycle gas, a large number of auxiliary equipment is necessary (compressors, fuel pumps, spool valves of the piston expansion machine), which also increases the losses of combined-cycle gas.

 The purpose of the invention is to increase the efficiency of the marine power plant.

 This goal is achieved by the fact that hot gas and seawater enter the profiled slave cylinder, ending with a nozzle, through special distributing devices, and a gas-water mixture takes off from the nozzle, creating a jet thrust.

 In one embodiment, the hot gas enters the working cylinder, for example, from the combustion chamber, in another embodiment, the hot gas enters the power turbine, and then into the working cylinder.

 Depending on the particular embodiment, the seawater and hot gas can be supplied to the working cylinder alternately through a rotating spool or through a hydraulic pulsator, or continuously through an ejector, the outboard water being the ejection medium.

 The essence of the invention lies in the fact that the seawater enters the profiled working cylinder, ending with a nozzle in which the discharged gas-water mixture is located, moves towards lower pressure towards the nozzle, freeing up the free volume of the working cylinder, which receives hot gas, which expands, simultaneously compressing and pushing the previous gas-water mixture through the nozzle, creating a jet thrust, then the hot gas mixes with the remaining sea water, forming a gas-water mixture, it cools, creating a discharge voltage required for admission to the working cylinder seawater and hot gas.

 The parameters of the working process of a ship power plant (power, fuel consumption, etc.) are determined by the ratio of hot gas and sea water in the working cylinder, as well as the profile of the working cylinder and its dimensions.

 The drawing shows the thermodynamic cycle of the ship power plant according to the proposed method.

 Process 1-2 - heat supply at constant pressure (this is possible with fuel combustion in the combustion chamber).

 Process 2-2'-3 - expansion of hot gas, for example, adiabatic after the combustion chamber. Options are possible: immediately in the working cylinder or previously in the power turbine, and then in the working cylinder.

 Process 3-4 - gas cooling in a working cylinder, for example, isobaric.

 Process 4-1 - gas compression to atmospheric pressure with heat removal, for example, isothermal.

,
где q₁ = C_p (t₂-t₁) - кол-во подведенного тепла;
C_р = 1,13 кДпс/кг·^oC - теплоемкость при постоянном давлении в диапазоне 30^oC ≤ t ≤ 1200^oC;
q₂ = C_p (t₃ - t₄) + RT₄ln·P₁/P₄ - количество отведенного тепла;

- газовая постоянная воздуха, тогда

или 54%.Ambient temperature:
T ₁ = 300 K (27 ^o C)
Environmental pressure:
P ₁ = 1 bar
Maximum cycle temperature:
T ₂ = 1500 K (1227 ^o C)
The pressure, for example, in the combustion chamber is constant and equal to atmospheric:
P ₂ = P ₁ = 1 bar
Adiabatic expansion end temperature:
T ₃ = 600 K (327 ^o C)
End pressure adiabatic expansion:
P ₃ = 0.04 bar
(from the adiabatic equation at K = 1.4 "- the adiabatic indices)
The gas cooling temperature is (theoretically) ambient temperature:
T ₄ = T ₁ = 300 K (27 ^o C)
Gas Cooling Pressure:
P ₃ = P ₄ = 0.04 bar
(from the equation of the isobaric process)
Thermodynamic cycle efficiency

,
where q ₁ = C _p (t ₂ -t ₁ ) is the amount of heat supplied;
C _p = 1.13 kDps / kg · ^o C - heat capacity at constant pressure in the range of 30 ^o C ≤ t ≤ 1200 ^o C;
q ₂ = C _p (t ₃ - t ₄ ) + RT ₄ ln · P ₁ / P ₄ - amount of heat removed;

is the gas constant of air, then

or 54%.

To assess the effective efficiency, we take into account thermal hydraulic losses, for example, in the combustion chamber η _{k, s} = 0.95-0.98, we take 0.96 (see Nigmatullin I.N. Thermal engines.- M.: Higher School, 1974 , p. 197).

The propulsion efficiency can be taken by analogy with a hydro-jet engine η _bhp = 0.6-0.7, we take η _bhp = 0.65 (Alekseev G.N. General heat engineering.- M .: Higher school, 1980, p. . 532).

Efficiency of a gas turbine η _gt = 0.65-0.8, take η _gt = 0.75 (Alekseev G.N. General heat engineering.- M.: Higher School, 1980, p. 452).

Then the effective efficiency of the ship's power plant
a) under item 1 η $\genfrac{}{}{0ex}{}{\text{1}}{\text{at}}$ _st = η _fc · η _gd · η _t = 0.96 · 0.65 · 0.54 = 0.34 or 34%
b) under item 2 η $\genfrac{}{}{0ex}{}{\text{2}}{\text{at}}$ _st = η _fc · η _gd · η _gt · η _t = 0.96 · 0.65 · 0.54 · 0.75 = 0.25 or 25%
The value of effective efficiency of 34 and 25% in both cases is greater than that of the prototype (10-15%).

Using the proposed method of operation of a marine power plant in comparison with existing ones provides the following advantages:
1) higher effective efficiency, which reduces operating costs (fuel, oil, etc.), increase the radius of the vessel;
2) a simpler design (no need for compressors, fuel pumps, piston expansion machines), and therefore, lower cost;
3) greater viability of the vessel (since the installation operates at atmospheric pressure, in the event of an emergency, it can operate in the mode of a pump and a pump to generate electricity).

Claims (5)

 1. The method of operation of a marine power plant by supplying overboard water and hot gas to the working cylinder, characterized in that in order to increase effective efficiency seawater enters the profiled working cylinder, ending with a nozzle in which there is a rarefied gas-water mixture, moves towards lower pressure to the nozzle, freeing up the free volume of the working cylinder, which receives hot gas, which expands, while compressing and pushing the previous gas-water mixture through the nozzle, creating reactive thrust, then the hot gas is mixed with the remaining sea water, forming a gas-water mixture, it is cooled, creating the necessary vacuum for entering rking cylinder seawater and hot gas.  2. The method according to claim 1, characterized in that the hot gas is pre-adiabatically expanded in the power turbine, and then enters the working cylinder.  3. The method according to p. 1, characterized in that the seawater and hot gas enter the working cylinder alternately through a rotating spool.  4. The method according to claim 1, characterized in that the seawater enters the working cylinder through a hydraulic pulsator and captures hot gas.  5. The method according to claim 1, characterized in that the seawater and hot gas enter the working cylinder continuously through the ejector, the ejection medium being sea water.