RU2095606C1 - Engine utilizing energy of heated vapor of fuel - Google Patents

Abstract

FIELD: rocket power plants, shaft drives. SUBSTANCE: engine includes member converting heat into energy of pressure in form of fuel brought in contact with heating device 2, heating device 2 proper, combustion chamber 3 with exhaust nozzle 13, air intake 14, starting system 21, vortex ejector 5 with cooling jacket 10 located at outlet of air intake 14, separator 6 intended for separation of mixture fed from ejector 5 and located between this ejector and combustion chamber 3 which is provided with prechamber vortex mixer 11. Air intake 14 may be provided with turbine 15. Separator 6 is provided with heat exchanger 7 at its inlet and condenser 9 at its outlet, with energy acceptor 8 located between them. Energy acceptor consists of expander 16 fitted with device 20 for taking off rotation power and throttle device 17 provided with vortex tube 18 having cooling jacket 19 which are connected in parallel. Ejector and separator form one stage of compression. EFFECT: enhanced efficiency. 2 cl, 4 dwg

Description

 The invention can be used as a jet propulsion system of continuous thrust, as well as a drive for rotating the shaft in vehicles and machines operating within the earth's atmosphere.

 A known engine comprising a starting system, an air intake with an ejector at the outlet for compressing the air entering through the air intake, and a combustion chamber with an exhaust nozzle and a heating device for heating fuel, converting heat to pressure energy [1] This engine relates to pressure engines, where fuel It is pumped under pressure through a heating device, evaporates and, as an ejecting working medium (ERT), is fed into a direct-jet ejector. In an ERT ejector in the form of a jet of fuel vapor, it draws air from the environment and compresses it, pumping it into the combustion chamber. A mixture of fuel vapor and air burns in the combustion chamber, giving energy for jet propulsion and heating the fuel. In series, the compression stages of the fuel vapor (in front of it) in order to increase the degree of compression, generally include the compression stages with exhaust gases, which also act as a direct-jet ejection method.

 The principle of ejection compression of air by fuel vapor using a fuel heating device is a common feature of the aforementioned invention and the subject of this invention. However, such negative features as the low compression ratio of a straight-blown ejector, the inverse relationship between the compression ratio of the ejectors and the ejection coefficient, and consequently the air flow rate, heating and saturation of the intake air by the combustion products, are the cause of the low compression ratio of the entire system, and therefore low pressure in the combustion chamber and low Efficiency. The elimination of these disadvantages was made possible by introducing into the design of the separator necessary for separating the mixture coming from the ejector, and making the ejector itself swirl with a cooling jacket connected to the separator and the heating device, and also due to the rejection of ejection by combustion products, which together is embodied in proposed engine and distinguishes it from the previous one. In addition, the use of the engine for performing rotational work is carried out in the known invention either by installing the engine on the rotor blades, or by blowing the turbine with hot exhaust gases, which is associated in the first case with its power supply, and in the second with the presence of a movable element with low reliability and resource due to heat stress. The proposed engine uses for similar purposes a rotational power take-off device, which is equipped with an expander, as well as a turbine located in the air intake and working in the intake air stream at ambient temperature, which does not exclude the use of an exhaust turbine operating in this case in a less energy-intensive mode, due to unloading it with an expander and an inlet turbine. In order to utilize the energy taken from the mixture to be separated, the separator located between the vortex ejector and the combustion chamber is made in the form of a heat exchanger at the inlet of the separator, a condenser at the outlet of the separator, and an energy acceptor located between the heat exchanger and the condenser and consisting of an expander and a throttle device connected to each other with the other, the throttle device provided with a vortex tube having a cooling jacket.

 The technical result of the invention is an engine with higher efficiency due to an increase in the compression ratio when the maximum combustion temperature is reached.

 This technical result is achieved by eliminating the dependence of the compression process on the mixture formation process, as well as by cooling the compressible air using devices included in the stage of the engine compression system: a separator separating the mixture coming from the vortex ejector, pressurized with fuel vapor, installed between the vortex ejector and the combustion chamber, as well as the cooling jacket of the vortex ejector and the ejection coefficient, the number of compression stages can be different depending on the purpose of the engine body and type of fuel.

In FIG. 1 shows a pneumatic hydraulic circuit of the engine, where the solid straight arrows show the movement of liquid fuel, wavy combustible steam, the dashed movement of air, the double (solid and dashed) movement of the mixture of air and combustible vapor, the dash-dotted movement of the combustible mixture, the double (solid and dash-dotted) movement of the adjusted hot ; in FIG. 2 graph of the cycle of operation of combustible steam; in FIG. 3 a plot of motor efficiency of compression ratio and intake air temperature of the heating gas, wherein the compression ratio σ and T ₁ <T ₂ <T _v (T _v stoichiometric combustion temperature); in FIG. 4 is a graph of the dependence of the ejection coefficient on the compression ratio of the ejector, where the ejection coefficient n G _in / G _ert ; G _in and G _ert consumptions of air and ERT respectively.

 Description of the engine.

 The engine, if used as a reactive power plant, operates as follows. Fuel under pressure created by the pump 1 (see Fig. 1) is pumped in accordance with the process 0-1 (see Fig. 2) into the heating device 2 in contact with the combustion chamber 3 (the application of the described heating method is one of the known options use in the engine building of various heating devices, each of which can be used in this engine depending on its specific purpose), where it (fuel) heats up, evaporates and overheats in accordance with processes 1-2, 2-3, 3-4. Superheated fuel vapor as an ERT is supplied to the nozzle apparatus 4 of the vortex ejector 5, where, performing work in accordance with process 4-5, it forms a vortex that compresses the air drawn in through the air inlet 14. The vortex ejector 5 is located at the outlet of the air inlet 14.

где G_в расход воздуха;
G_эрт расход ЭРТ;
G_гор расход горючего.When designing the ejector 5, it must be taken into account that its compression ratio should correspond to the maximum engine efficiency for a given combustion temperature, which should also be chosen maximum, i.e., stoichiometric or close to it, in order to increase the efficiency (see Fig. 3). If an increase in the combustion temperature in pressure engines is entirely possible due to the absence of heat-stressed turbines, then the choice of compression ratio is limited due to its inverse relationship and the ejector ejection coefficient (see Fig. 4). Namely, in engines with direct ejector pressurization of the combustion chamber, the ejection coefficient determines the amount of air in the mixture coming from the ejector to the combustion chamber, which should not be less than the amount required for guaranteed ignition and combustion of the combustible mixture. For the most common regular hydrocarbon fuels, the limit of the air content in the mixture is at least 95-90%, which corresponds to an excess of oxidizing agent a ≈ 0.4 0.6 and a ratio of components K ≈ 6 - 9. In the case of direct pressurization of the combustion chamber by an ejector with an ERT in in the form of fuel vapor without the use of supercharged steps from exhaust gases, the minimum value of the ejection coefficient (n _ezh ) is determined by the minimum acceptable value of the coefficient of the ratio of components n _ezh K

where G _{is the} air flow;
G _erythritic consumption ERT;
G _mountains fuel consumption.

где T_о.в. температура окружающего воздуха;
σ степень сжатия эжектора;
K_в, K_эрт соответственно показатели адиабаты воздуха и горючего пара;
e степень расширения ЭРТ (e P_эрт/P_вых, P_вых давление смеси на выходе из эжектора).In engines using exhaust gases as ERTs, the required minimum ejection coefficient is greater than the ratio of the components in view of the presence of exhaust gases that do not support combustion in the medium ejected into the combustion chamber, which requires a reduction in the compression ratio of the ejector. Therefore, at a fuel supply pressure, for example, P _{ert of} 300 atm, and a temperature of heating of combustible steam T _{ert of} 300 ^o C, taken from the condition of specific strength and heat resistance of the elements of the engines made, as well as from the condition of thermal stability of the fuel, the compression ratio of the ejector with a hypothetical efficiency of 99% for n _ezh ≥ 6 can be found by solving a system of equations based on the ejector efficiency formula

where T _o.v. ambient temperature;
σ compression ratio of the ejector;
K _in , K _ert, respectively, the adiabatic parameters of air and combustible steam;
e EFV expansion ratio (e P _EFV / P _O, P _O mixture pressure at the outlet from the ejector).

где P_вх давление воздуха на входе в эжектор.The system has the form

where P _Rin air pressure at the inlet to the ejector.

где η_соп КПД реактивного сопла двигателя (как правило достаточно высок и составляет 0,95 0,98);
T_с температура нагрева газа (T_с ≈ 1200-1300 при α 0,4),
степень сжатия, соответствующая максимальному КПД двигателя, составляет s_н 11. Например, для двигателя, летящего на высоте 10 км со скоростью V 250 м/с, при температуре нагрева газа T_с ≈ 1300 K, учитывая α 0,4, требуемая наивыгоднейшая степень сжатия составит s_н 19, что соответствует степени сжатия эжектора

где σ_v степень сжатия от скоростного напора,
в связи с чем, коэффициент эжекции составит n_эж=0,6. При непосредственном наддуве эжектором камеры сгорания, что свойственно конструкции существующих (эжекторных) двигателей давления, n_эж=0,6 обеспечит в камере сгорания α 0,04, что в 10 раз ниже предельно допустимого для горения значения, указанного в условии. Устранение зависимости от коэффициента эжекции путем разделения процессов сжатия и смесеобразования позволяет повысить степень сжатия до наивыгоднейшего значения или близкого к нему, сохраненив расчетное a Так, из вышеописанного примера видно, что, например, при допустимом n_эж 1 возможно увеличение степени сжатия до 8, а независимость a от n_эж позволяет выбрать любое соотношение компонентов вплоть до a 1, что в условиях полета на вышеуказанной высоте и скорости, соответствует T_c≈2500 K. Полный КПД двигателя

,
выраженный через удельную тягу имеет вид

,
где A тепловой эквивалент работы;
R тяга;
R_уд удельная тяга;
V скорость полета;
B_r расход газа через двигатель;
n_u теплотворность горючего.Substituting the above values and solving the system, it is not difficult to see that with the minimum permissible n _ej for an ejector with the highest possible efficiency (percent fractions in the range from 99 to 100% will not have a significant effect, therefore, their possible achievement is not taken into account), the degree value compression ratio is σ 1.735. Whereas, according to the expression for the most favorable compression ratio (s _n )

where η _sop efficiency of the jet nozzle of the engine (usually quite high and is 0.95 0.98);
T _s gas heating temperature (T _s ≈ 1200-1300 at α 0.4),
the compression ratio corresponding to the maximum engine efficiency is s _n 11. For example, for an engine flying at an altitude of 10 km at a speed of V 250 m / s, at a gas heating temperature of T _s ≈ 1300 K, taking into account α 0.4, the most favorable degree is required compression will be s _n 19, which corresponds to the compression ratio of the ejector

where σ _{v the} compression ratio from the pressure head,
in this connection, the ejection coefficient will be n _ezh = 0.6. With direct ejector pressurization of the combustion chamber, which is characteristic of the design of existing (ejector) pressure engines, n _ezh = 0.6 will provide α 0.04 in the combustion chamber, which is 10 times lower than the maximum permissible value for combustion specified in the condition. Eliminating the dependence on the ejection coefficient by separating the compression and mixing processes allows increasing the compression ratio to the best value or close to it, while maintaining the calculated a So, from the above example it can be seen that, for example, with a valid n _ezh 1, the compression ratio can be increased to 8, and the independence of a from n _ej allows you to choose any ratio of components up to a 1, which in flight conditions at the above altitude and speed corresponds to T _c ≈ 2500 K. The full engine efficiency

,
expressed through specific thrust has the form

,
where A is the thermal equivalent of work;
R thrust
R _ud specific thrust;
V flight speed;
B _r gas flow through the engine;
n _u fuel calorific value.

,
то

,
где C_с скорость истечения газа из сопла, зависящая от температуры газа T_с и степени сжатия σ, выражена

где β газовая постоянная;
P_ат атмосферное давление;
P_v давление набегающего воздуха;
k показатель адиабаты газа;
P_vσ давление в камере сгорания.If a

,
then

,
where C _{с the} rate of gas outflow from the nozzle, depending on the gas temperature T _c and compression ratio σ, is expressed

where β is the gas constant;
P _at atmospheric pressure;
P _v air pressure;
k is the adiabatic index of gas;
P _v σ pressure in the combustion chamber.

, T_c' k', β′, сравнивают его КПД (при прочих равных условиях) с КПД известных эжекторных двигателей

Подставив вышеупомянутые, принятые в качестве примера, значения, получают

Следовательно, при использовании одного и того же типа горючего и полете в равных условиях двух эжекторных двигателей одинаковых тяг, КПД двигателя s 8 благодаря независимому от a процессу эжекции в 2,5 раза выше (степень сжатия, равная 8, и соответствующее увеличение КПД двигателя не являются предельными для предлагаемого двигателя и взяты лишь в качестве примера). С целью разделения процессов смесеобразования и сжатия в предлагаемом двигателе предусмотрен сепаратор 6, выделяющий из смеси, выходящей из эжектора 5, лишнее горючее, делая смесь пригодной для горения. Таким образом, сепаратор выдает готовую для горения смесь, нуждающуюся лишь в частичной коррекции, посредством регулятора соотношения компонентов, в случае отклонения от расчетного значения. Сепаратор 6 состоит из теплообменника 7, энергоакцептора 8, представляющего собой комбинацию из таких устройств, как детандер 16, дроссель 17 и вихревая труба 18 с рубашкой охлаждения 19 (все эти устройства и их комбинации сами по себе хорошо известны, в связи с чем не нуждаются в описании) и конденсатор 9. Сепаратор 6 работает по принципу выхолаживания, что позволяет утилизировать отобранную от разделяемой смеси энергию. Горючий пар в смеси с воздухом из эжектора 5 поступает в теплообменник 7 сепаратора 6, где частично охлаждается согласно процессу 5-6, отдавая тепло холодному горючему, протекающему по жидкостному тракту теплообменника 7. Далее пар поступает в энергоакцептор 8, где окончательно охлаждается, совершая работу 6-7, после чего сконденсированное в процессе 7-0 лишнее горючее скапливается в конденсаторе 9 для подачи оттуда посредством насоса 1, через рубашку охлаждения 19 вихревой трубы 18, жидкостный тракт теплообменника 7 и рубашку охлаждения 10 эжектора 5 в нагревательное устройство 2, замыкая цикл. Рубашка охлаждения 10 эжектора 5 охлаждает сжимаемый воздух протекающим горючим, уменьшая потребную работу, идущую на сжатие, для использования сэкономленной ее части на увеличение коэффициента эжекции, облегчая таким образом работу сепаратора 6, увеличивая процент воздуха в смеси. Дополнительное тепло, поглощенное горючим в рубашке 19, теплообменинке 7 и рубашке 10, частично экономит энергию, затрачиваемую на нагрев горючего в нагревательном устройстве 2. Детандер 16 является приводом насосов 1 и 12. Готовая для горения смесь поступает из конденсатора 9 в следующую ступень для дальнейшего сжатия или в предкамерный вихревой смеситль 11, куда подается с тангенциальной составляющей пар горючего из нагревательного устройства 2 для коррекции и дополнительного перемешивания горючей смеси посредством вихря. Общее количество горючего, протекающего через двигатель, пополняется из бака посредством насоса 12 на величину расхода сгорающего горючего пара. Из предкамерного вихревого смесителя 11 смесь поступает в камеру сгорания 3, где сгорает при повышенном давлении, нагревая горючее в нагревательном устройстве 2 и образуя выхлопные газы. Выхлопные газы покидают камеру сгорания 3 через реактивное сопло 13, создавая тягу.Expressing efficiency through the flow rate and designating engine parameters with alpha-independent combustion chamber pressurization as

, T _{c '} k', β ′, compare its efficiency (ceteris paribus) with the efficiency of known ejector engines

Substituting the above, taken as an example, the values get

Therefore, when using the same type of fuel and flying under equal conditions two ejector engines of the same thrust, the efficiency of the s 8 engine is 2.5 times higher due to the ejection process independent of a (compression ratio equal to 8, and the corresponding increase in the engine efficiency is not are the limit for the proposed engine and are taken only as an example). In order to separate the processes of mixture formation and compression in the proposed engine, a separator 6 is provided, which separates excess fuel from the mixture leaving the ejector 5, making the mixture suitable for combustion. Thus, the separator produces a ready-to-burn mixture, which needs only partial correction by means of a component ratio regulator in case of deviation from the calculated value. The separator 6 consists of a heat exchanger 7, an energy acceptor 8, which is a combination of devices such as an expander 16, a throttle 17 and a vortex tube 18 with a cooling jacket 19 (all of these devices and their combinations are well known per se, and therefore do not need in the description) and the capacitor 9. The separator 6 operates on the principle of cooling, which allows you to utilize the energy selected from the shared mixture. Combustible steam mixed with air from the ejector 5 enters the heat exchanger 7 of the separator 6, where it is partially cooled according to the process 5-6, transferring heat to the cold fuel flowing through the liquid path of the heat exchanger 7. Next, the steam enters the energy acceptor 8, where it is finally cooled, doing work 6-7, after which the excess fuel condensed in the process 7-0 accumulates in the condenser 9 for supply from there by the pump 1, through the cooling jacket 19 of the vortex tube 18, the liquid path of the heat exchanger 7 and the cooling jacket 10 ejector and 5 to the heating device 2, closing the cycle. The cooling jacket 10 of the ejector 5 cools the compressed air with flowing fuel, reducing the required work going to the compression, to use the saved part to increase the ejection coefficient, thereby facilitating the operation of the separator 6, increasing the percentage of air in the mixture. The additional heat absorbed by the fuel in the jacket 19, the heat exchanger 7 and the jacket 10 partially saves the energy spent on heating the fuel in the heating device 2. The expander 16 is the drive of the pumps 1 and 12. The mixture ready for combustion comes from the condenser 9 to the next stage for further compression or into the pre-chamber vortex mixer 11, where it is supplied with the tangential component of the fuel vapor from the heating device 2 for correction and additional mixing of the fuel mixture by means of a vortex. The total amount of fuel flowing through the engine is replenished from the tank through the pump 12 by the amount of flow of combustible combustible steam. From the pre-chamber vortex mixer 11, the mixture enters the combustion chamber 3, where it burns at elevated pressure, heating the fuel in the heating device 2 and forming exhaust gases. Exhaust gases leave the combustion chamber 3 through the jet nozzle 13, creating a draft.

 If necessary, the proposed engine rotational work, the conversion of engine energy into energy of rotation of the shaft is carried out by installing in the air intake 14 of the turbine 15, operating on the suction. The turbine 15 is driven by air sucked by the ejector 5 from the external environment. This method of obtaining torque does not exclude the use of an exhaust turbine. In addition, the energy used for rotation is taken from the expander using a rotary power take-off device 20. The starting system 21 is not described, because it is one of the well-known starting systems, each of which can be used in the proposed engine depending on its specific destination.

Claims (2)

 1. An engine using the energy of a heated steam of fuel, comprising a starting system, an air intake with at least one ejector at the outlet for compressing the air entering through the air intake, and at least one combustion chamber with an exhaust nozzle and a heating device for heating the fuel, which converts heat pressure energy, characterized in that it is equipped with at least one separator for separating the mixture coming from the ejector, placed between the ejector and the combustion chamber, and each ejector is made ihrevym and provided with a cooling jacket.  2. The engine according to claim 1, characterized in that each combustion chamber is provided with an input device in the form of a pre-chamber vortex mixer, an air intake is equipped with a turbine, and each separator is made in the form of a heat exchanger at the inlet of the separator, a condenser at the outlet of the separator, and an energy acceptor located between heat exchanger and condenser and consisting of an expander and a throttle device connected to each other, and the throttle device is equipped with a vortex tube having a cooling jacket, and the expander is equipped with a device The rotational power selection property for the rotational work of the engine, in addition, each vortex ejector is equipped with a nozzle apparatus for supplying fuel vapor as an ejecting working fluid, and the cooling jacket of each vortex ejector is connected to a separator and a heating device.

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