CN104729855A - Method for assessing influences of experiment gas pollution on supersonic combustion ramjet engine performance - Google Patents

Abstract

The invention discloses a method for assessing influences of experiment gas pollution on supersonic combustion ramjet engine performance. The method aims to solve the problem of a working medium pollution effect existing in supersonic combustion ramjet engine ground tests. A typical work state point of an engine is determined by building an engine model; according to different heater conditions under a parameter matching rule or different matching rules of the same combustion heater, inflow conditions of the engine are calculated, and performance comparison calculation of a supersonic combustion chamber and the supersonic combustion ramjet engine is carried out under pure air inflow and polluted air inflow. Rules of influences of the polluted air inflow generated by different combustion heaters on engine performance are researched in the aspect of combustion heating modes, rules of the influences of the polluted air inflow on the engine performance under different inflow parameter matching simulation schemes are researched in the aspect of a ground test parameter simulation rule, and accordingly it is determined that simulation parameters obtain a result more closer to a result generated when pure air inflow exists, and beneficial reference is provided for ground test engine performance assessment.

Description

A kind of experimental gas pollutes the appraisal procedure on Investigation of Scramjet Engine Performance impact

Technical field

The invention belongs to scramjet engine experimental technique field, specifically, relate to a kind of experimental gas and pollute the appraisal procedure that Investigation of Scramjet Engine Performance is affected.

Background technology

Combustion heating wind-tunnel applies in scramjet engine ground experiment widely.Concerning burning heater, it produces H2O and CO2 pollution components and some micro-free radicals, the NOx product of suitable content, change the characteristic of the aspects such as the ermal physics of test gas, chemistry, pollution components can at rocket engine ground test, especially apply physics, the chemical affect of " additionally " in combustion chamber components test, namely produce " polluting effect ".How determining different burning heater wind-tunnel exit flow matching parameter and how to assess the impact of polluting effect, is the important topic of scramjet engine research field.

Existing disclosed technical literature " Estimation of Enthalpy Effects in Direct-connectDual-Mode Combustor " (Journal thermal science and technologly, 2011, Vol.6, No.2:289-296) have studied two kinds of well heaters in, i.e. electric heater and burning heater, two kinds of matching ways, namely mate the performance of scramjet engine firing chamber under stagnation temperature, coupling total enthalpy condition.Under different well heater conditions, how to determine experimental facilities matching criterior, how to assess engine performance study under different inlet flow conditions, have no open source literature and deliver." polluting effect " contrast test technology is quite complicated in addition, not easily realize the important parameter coupling of two kinds of test gases, as the coupling of test model, incoming flow parameter, fuel oil oil-gas ratio, strictly mating the engine performance study on assessing method under important parameter, pure air and contaminated air there are no report.

The deficiency of existing research is primarily of following two aspects: (1) is to the still ununified simulation rules of burning heater exit flow matching parameter scheme; (2) the rocket engine ground test result from burning heater not yet has assessment and revises criterion.The present invention is intended to assessment different heating device and different incoming flow parameter matching scheme to the impact of engine performance, determines to assess and revise the method for scramjet engine ground experiment under contaminated air inlet flow conditions.

Summary of the invention

In order to assess different heating device and different incoming flow parameter matching scheme to the impact of engine performance, the method of scramjet engine ground experiment under determining assessment and revising contaminated air inlet flow conditions, the present invention proposes a kind of experimental gas and pollutes the appraisal procedure affected Investigation of Scramjet Engine Performance, according to different parameters matching criterior, this method determines that different burning heater and pure air carry out the air-flow component of flow export, by calculate engine performance parameter under different inlet flow conditions and assess engine performance under different inlet flow conditions and and under pure air condition engine performance contrast, with the difference of engine performance under Different matching criterion under assessment different heating device scheme.

The technical solution adopted for the present invention to solve the technical problems is: set up engine computation model, determine engine exemplary operation state point, calculate engine inlet flow conditions according to different heating device conditioned disjunction same burning heater Different matching criterion under parameter matching criterion, carry out pure air incoming flow and contaminated air to flow down supersonic combustor and Investigation of Scramjet Engine Performance comparing calculation.The contaminated air incoming flow of different burning heater generation is studied to the affecting laws of engine performance from combustion heating mode, contaminated air incoming flow is studied different incoming flow parameter matching modeling scheme to the affecting laws of engine performance from ground experiment parameter simulation criterion, determine analog parameter, adopt the mode polluting heating to obtain and result more close during pure air incoming flow, for ground experiment parameter simulation criterion choose, engine Performance Evaluation provides foundation under combustion heating mode.

Experimental gas pollutes the appraisal procedure on Investigation of Scramjet Engine Performance impact, it is characterized in that comprising the following steps:

Step 1. carries out pure air incoming flow scramjet engine complete machine flow field, performance simulation, as benchmark;

Step 2. with a certain burning heater and alcohol burn heating, kerosene combustion heating or oxyhydrogen combustion well heater contaminated air for working medium, relative to pure air incoming flow conditions parameter, for different parameters matching scheme:

(1) stagnation temperature, stagnation pressure, Mach number, oxygen mole percentage approach is mated;

(2) static temperature, static pressure, Mach number, oxygen mole percentage approach is mated;

(3) total enthalpy, static pressure, Mach number, oxygen mole percentage approach is mated;

(4) stagnation temperature, static pressure, Mach number, oxygen mole percentage approach is mated;

(5) total enthalpy, stagnation pressure, Mach number, oxygen mole percentage approach is mated;

(6) total enthalpy, dynamic pressure, Mach number, oxygen mole percentage approach is mated;

Carry out the numerical evaluation that contaminated air incoming flow affects Investigation of Scramjet Engine Performance, the difference under comparative analysis different incoming flow parameter matching scheme when engine performance and pure air incoming flow;

Step 3. is under a certain parameter matching scheme condition, to oxyhydrogen combustion heating, alcohol burn heating, kerosene combustion heating three kinds of contaminated air incoming flow scramjet engines carry out numerical evaluation, under comparative analysis different combustion heating contaminated air incoming flow engine performance difference and with difference during pure air incoming flow;

Step 4. calculating and setting condition: in calculating, governing equation adopts and can press averaged Navier-Stokes equation and composition equation, convective flux is chosen AUSM and is divided form, viscosity flux calculates the cell centered scheme adopted based on Gauss theorem, gets k-ω-SST two-equation turbulence model; Chemical Reaction Model adopts Hautman to the accurate overall budget Chemical Reaction Model of eight component four steps of hydrocarbon CnH2n+2, as shown in the formula:

The chemical dynamic model adopted during the numerical simulation of hydrogen fuel scramjet engine is the finite-rate reaction model of seven component eight step elementary reactions under the H2/O2 system simplified:

Seven component eight step reaction finite-rate reaction models under H2/O2 system

The analysis of step 5. result of calculation.

Beneficial effect

A kind of experimental gas that the present invention proposes pollutes the appraisal procedure on Investigation of Scramjet Engine Performance impact, for solving working medium " polluting effect " problem that existing scramjet engine ground experiment exists, in foundation assessment contaminated air, pollution components is to the method for kerosene stock super burn engine performance impacts, by engine performance under assessment different heating device and different parameters matching criterior, obtain different incoming flow parameter matching scheme, the conclusion that different combustion heating contaminated air affects engine overall performance, from incoming flow parameter, the angle of engine performance impacts tentatively determines contaminated air incoming flow rocket engine ground test parameter simulation criterion.

Accompanying drawing explanation

Below in conjunction with drawings and embodiments, the appraisal procedure that a kind of experimental gas of the present invention is polluted Investigation of Scramjet Engine Performance affects is described in further detail.

Fig. 1 is scramjet engine complete machine computational grid schematic diagram.

Fig. 2 (a), Fig. 2 (b) are engine inner flow passage wall pressure correlation curve when coupling stagnation temperature, stagnation pressure, Mach number.

Fig. 3 (a), Fig. 3 (b) are engine inner flow passage wall pressure correlation curve when coupling stagnation temperature, static pressure, Mach number.

Fig. 4 (a), Fig. 4 (b) are engine inner flow passage wall pressure correlation curve when coupling static temperature, static pressure, Mach number.

Fig. 5 (a), Fig. 5 (b) are engine inner flow passage wall pressure correlation curve when coupling total enthalpy, stagnation pressure, Mach number.

Fig. 6 (a), Fig. 6 (b) are engine inner flow passage wall pressure correlation curve when coupling total enthalpy, static pressure, Mach number.

Embodiment

The present embodiment is the appraisal procedure that a kind of experimental gas pollutes on Investigation of Scramjet Engine Performance impact.

Consult Fig. 1 ~ Fig. 6 (a), Fig. 6 (b), the present embodiment experimental gas pollutes the appraisal procedure on Investigation of Scramjet Engine Performance impact, and concrete steps are as follows:

The first step, sets up engine performance computation model;

Provide the engine performance computation model and grid that comprise engine runner.Determine that computing mode is: flight Mach number 6.0, height 26km state, adopt hydrogen fuel, equivalent oil-gas ratio is 0.6.

Second step, determines engine incoming flow conditions;

(1) determination of engine inlet flow conditions under Different matching scheme.As table 2 gives six kinds of different parameters matching schemes, table 3 give alcohol burn heater outlet contaminated air coupling different schemes under engine inlet flow conditions.

(2) determination of the engine inlet flow conditions of different burning burning heater outlet under same matching scheme.Under table 4 gives static temperature static pressure Mach number matching scheme, oxyhydrogen combustion well heater, alcohol burn well heater and kerosene heater export inlet flow conditions.

The matching parameter of table 2 contaminated air incoming flow parameter matching scheme is selected

Under table 3 pure air incoming flow and Different matching scheme alcohol combustion heating contaminated air incoming flow parameter with simulated flight Mach number 6.0 state for benchmark

Table 4 pure air incoming flow and coupling static temperature, static pressure scheme time different combustion heating contaminated air incoming flow parameter with simulated flight Mach number 6.0 state for benchmark

3rd step, the calculating of engine performance and analysis; After inlet flow conditions is determined, according to aforesaid calculating and setting, jet flow field and performance can be calculated.

Table 5 gives the contrast of pure air incoming flow with engine overall performance parameter during hydrogen burning heating contaminated air different incoming flow parameter matching scheme.Compared with during pure air incoming flow, during contaminated air incoming flow, engine specific thrust, specific impulse decline all to some extent, and different incoming flow parameter matching scheme can cause different engine performance difference.

Table 5 engine performance parameter contrasts

Under table 6 gives scheme four condition, engine performance comparison under different burning heater condition when namely mating total enthalpy, static pressure.

The four times engine performance parameter contrasts of table 6 scheme

The present embodiment shows: flight Mach number Ma=6.0, the Live Flying condition of height H=25km is normal condition, equivalent oil-gas ratio ER=0.6, to the flow field of combustion heating wind tunnel test gas scramjet engine under different combustion heating mode and different parameters matching scheme with performance has carried out calculating and comparative evaluation shows:

(1) height that under pure air incoming flow, the thrust of engine, specific thrust, specific impulse and inner flow passage wall pressure flow down than test for contamination gas;

(2) under hydrogen burning type of heating, the best performance of engine when incoming flow test gas coupling total enthalpy, static pressure, Mach number, and the performance flowed down with pure air is the most close; And the performance of engine differs maximum with the engine performance that pure air flows down when parameter matching stagnation temperature, stagnation pressure, Mach number;

(3) under kerosene combustion heating mode, the best performance of engine when incoming flow test gas parameter matching static temperature, static pressure, Mach number, and the performance flowed down with pure air is the most close; And the performance of engine differs maximum with the engine performance that pure air flows down when parameter matching stagnation temperature, stagnation pressure, Mach number;

(4) under alcohol burn type of heating, the best performance of engine when incoming flow test gas parameter matching static temperature, static pressure, Mach number, and the performance flowed down with pure air is the most close; And the performance of engine differs maximum with the engine performance that pure air flows down when parameter matching stagnation temperature, stagnation pressure, Mach number;

(5) when test gas parameter matching scheme is identical, engine performance under hydrogen burning type of heating is more excellent than the performance under kerosene and alcohol burn type of heating, the performance flowed down with pure air is the most close, and under kerosene and alcohol burn type of heating, the performance difference of engine is little.

Claims (1)

1. experimental gas pollutes the appraisal procedure on Investigation of Scramjet Engine Performance impact, it is characterized in that comprising the following steps:

Step 1. carries out pure air incoming flow scramjet engine complete machine flow field, performance simulation, as benchmark;

Step 2. with a certain burning heater and alcohol burn heating, kerosene combustion heating or oxyhydrogen combustion well heater contaminated air for working medium, relative to pure air incoming flow conditions parameter, for different parameters matching scheme:

(1) stagnation temperature, stagnation pressure, Mach number, oxygen mole percentage approach is mated;

(2) static temperature, static pressure, Mach number, oxygen mole percentage approach is mated;

(3) total enthalpy, static pressure, Mach number, oxygen mole percentage approach is mated;

(4) stagnation temperature, static pressure, Mach number, oxygen mole percentage approach is mated;

(5) total enthalpy, stagnation pressure, Mach number, oxygen mole percentage approach is mated;

(6) total enthalpy, dynamic pressure, Mach number, oxygen mole percentage approach is mated;

Carry out the numerical evaluation that contaminated air incoming flow affects Investigation of Scramjet Engine Performance, the difference under comparative analysis different incoming flow parameter matching scheme when engine performance and pure air incoming flow;

Step 3. is under a certain parameter matching scheme condition, to oxyhydrogen combustion heating, alcohol burn heating, kerosene combustion heating three kinds of contaminated air incoming flow scramjet engines carry out numerical evaluation, under comparative analysis different combustion heating contaminated air incoming flow engine performance difference and with difference during pure air incoming flow;

Step 4. calculating and setting condition: in calculating, governing equation adopts and can press averaged Navier-Stokes equation and composition equation, convective flux is chosen AUSM and is divided form, viscosity flux calculates the cell centered scheme adopted based on Gauss theorem, gets k-ω-SST two-equation turbulence model; Chemical Reaction Model adopts Hautman to the accurate overall budget Chemical Reaction Model of eight component four steps of hydrocarbon CnH2n+2, as shown in the formula:

$C_n{H}_{2n+2}\→\frac{n}{2}{C}_2{H}_4+H_2---\left(1\right)$

$C_2{H}_4+O_2\↔2\mathrm{CO}+2H_2---\left(2\right)$

$2\mathrm{CO}+O_2\↔{2\mathrm{CO}}_2---\left(3\right)$

${2H}_2+O_2\↔{2H}_{2}O---\left(4\right)$

The chemical dynamic model adopted during the numerical simulation of hydrogen fuel scramjet engine is the finite-rate reaction model of seven component eight step elementary reactions under the H2/O2 system simplified:

H ₂/ O ₂seven component eight step reaction finite-rate reaction models under system

The analysis of step 5. result of calculation.