CN202056882U

CN202056882U - Microminiature combustor

Info

Publication number: CN202056882U
Application number: CN2011200612940U
Authority: CN
Inventors: 范爱武; 刘思远; 张若昀; 杨金国; 刘伟
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2011-03-09
Filing date: 2011-03-09
Publication date: 2011-11-30
Anticipated expiration: 2021-03-09

Abstract

The utility model discloses a microminiature combustor which comprises a blunt body, preheating channels and a combustion chamber; the preheating channels and the combustion chamber are of a flat plate type; the blunt body has a triangular or round section and is arranged at the inlet of the combustion chamber, the ratio of the width of the blunt body to that of the combustion chamber is 0.3-0.6; the two preheating channels are both L-shaped and are respectively arranged at the upper side and the lower side of the combustion chamber, and the outlets of the preheating channels are both communicated with the inlet of the combustion chamber. The microminiature burner overcomes the deficiencies of the prior art, and reduces energy needed by ignition, shortens the ignition lag time and decreases exhaust heat loss by preheating and catalyzing fuel and air (when non-premixed combustion mode is adopted), or mixture of the fuel and air (when premixed combustion mode is adopted), and fully mixes the fuel with the air, prolongs the fuel retention time and stabilizes the flame by a low-speed high-temperature flux area formed after the blunt body is utilized. Therefore, the microminiature burner can effectively expand the constant-combustion limit, improve the combustion efficiency, and is widely applicable to various microminiature power systems.

Description

A kind of mini combustion device

Technical field

The utility model belongs to the technical field of gas combustion, refers in particular to the burner that thermal source or high temperature source of the gas are provided for the microminiature power set.

Background technology

Along with the fast development of micro-processing technology, various microelectromechanical systems and equipment continue to bring out, as portable electric appts such as micro-satellite, miniature propulsion system, microrobot and mobile phones.These equipment are mostly driven by chemical cell at present, yet there are shortcomings such as energy density is little, volume and weight is big, the charging interval is long in chemical cell, and hydrogen and hydrocarbon fuels have high tens times energy density with respect to chemical cell.Energy density as the typical liquid hydrocarbon fuels is about 45MJ/kg, and the energy density of best lithium battery is about 1.2MJ/kg.Therefore, the microminiature dynamical system based on burning has the great potential of competing with lithium battery.At present researchers produced little combustion gas turbine, little rotary engine, little propulsion system, low-grade fever photovoltaic generating system (μ-TPV) and low-grade fever electric system (and μ-TE), or the like.Wherein, micro-burner is the critical component of microminiature dynamical system.Since the nineties in 20th century, obtained the great attention of countries in the world about the research of micro-combustion.

In the mini combustion device, because the long-pending ratio with volume of combustor surface is wanted big two to three orders of magnitude with respect to conventional yardstick, feasible radiation loss by wall increases greatly, wall also increases greatly to the probability of catching of chemical reaction free radical simultaneously, therefore, the flame holding variation takes place flame-out easily.In addition, because the combustion chamber physical dimension is too little, the gas time of staying therein is too short, and fuel and air often have little time complete reaction and just be blown the combustion chamber, not only causes efficiency of combustion to reduce, and the blow-off limit of fuel is also dwindled greatly with steady combustion scope.

In order to improve the stability of flame in the mini combustion device, the main way that adopts thermal cycle and catalytic reaction of researchers.Research group as American South University of California, northeastern Japan university and Tsing-Hua University adopts so-called " swiss roll (Swiss-Roll) " structure.But the three-dimensional structure of this burner complexity makes its processing very difficult.In addition, clock Beijing etc. has proposed the microminiature catalytic burner, yet the catalytic effect of catalyst is not lasting yet.The research group of Singapore has then developed sudden expansion type mini combustion device with the level and has come the retention flame, has obtained certain effect, but has increased system's machining complexity, and the existence of step has simultaneously reduced the compactedness of burner.

Summary of the invention

The purpose of this utility model is for a kind of mini combustion device is provided, and this burner has compact conformation, surely fires the high characteristics of wide ranges and efficiency of combustion.

A kind of mini combustion device that the utility model provides is characterized in that this burner comprises bluff body, first, second preheating channel and combustion chamber; First, second preheating channel and combustion chamber are plate; First, second preheating channel is respectively equipped with the gas access, and the combustion chamber is provided with the tail gas outlet;

Bluff body is installed in the porch of combustion chamber, the width W of bluff body _bWidth W with the combustion chamber _cRatio be between 0.3 to 0.6; First, second preheating channel is the L type, and is arranged in the upper and lower both sides of combustion chamber, and all is communicated with the inlet of combustion chamber.

Advantage of the present utility model is that in the combustion chamber both sides are provided with preheating channel up and down, has avoided the combustion chamber wall surface and extraneous direct heat transfer of high temperature like this, thereby has significantly reduced the radiation loss of combustion chamber.In addition, fuel and air when premixed combustion mode (adopt non-) or their premix (when adopting the premixed combustion mode) are before entering the combustion chamber, carry out convection current and radiation heat transfer by these two runners and combustion chamber wall surface, reach the purpose of preheating, can reduce the required energy of igniting like this, shorten and catch fire time expand.Moreover the existence of bluff body not only can be played and strengthen fuel and Air mixing effect when premixed combustion mode (adopt non-), and can utilize the recirculating zone of the low speed high temperature that its rear portion forms to come the retention flame well.Because bluff body can make flame keep being symmetrically distributed in the combustion chamber, can avoid because uneven thermal stress causes the damage of burner.The bluff body surface also can spray catalyst, thereby can further reduce the required activation energy that catches fire, and makes to catch fire in advance, and fuel and air have sufficient time to carry out chemical reaction, and guaranteeing also has high efficiency of combustion when higher intake velocity.The high-temperature flue gas that the utility model produces can be used for providing thermal source for minisize thermoelectric device or miniature hot photovoltaic system, also can be used as the high-temperature fuel gas of miniature propulsion system, produces thrust by follow-up jet pipe.

Of the present utility modelly be also advantageous in that it both had been applicable to non-premixed combustion, also be applicable to premixed combustion, specifically adopt which kind of combustion system reasonably to select according to actual conditions.

Description of drawings

Fig. 1 is the two-dimensional representation of the utility model structure:

Wherein 1,2. inlet, 3. tail gas outlet, 4. bluff body, 5,6. preheating channel, 7. combustion chamber

Fig. 2 is the 3 d effect graph of Fig. 1.

Fig. 3 is the blow-off limit comparison curves of the utility model embodiment and single flat template micro-burner;

Fig. 4 is the efficiency of combustion comparison curves of the utility model embodiment and single flat template micro-burner.

The specific embodiment

Below in conjunction with drawings and Examples the utility model is described in further detail, but following examples only are illustrative, protection domain of the present utility model is not subjected to the restriction of these embodiment.

As shown in Figure 1, the mini combustion device that provides of the utility model comprises

gas access

1 and 2, tail gas outlet 3, bluff body 4, preheating

channel

5 and 6 and combustion chamber 7.Preheating

channel

5 and 6 and combustion chamber 7 be plate.

Bluff body 4 is installed in the porch of combustion chamber, and the bluff body cross section is a triangle or cylindrical, and its surface can spray platinum common catalyst such as (Pt).The width W of bluff body 4 _bWidth W with combustion chamber 7 _cRatio be between 0.3 to 0.6, preheating

channel

5 and 6 is the L type, and is arranged in the upper and lower both sides of combustion chamber 7, preheating

channel

5 and 6 outlet all are communicated with the inlet of combustion chamber 7.

Fuel and air when premixed combustion mode (adopt non-), perhaps their premix when mode (adopt premixed combustion) 1 and 2 enters the inlet of plate micro combustor 7 through preheating

channel

5 and 6 from entering the mouth respectively, the two tentatively mixes in the porch, further fully mix at bluff body 4 rears then when premixed combustion mode (adopt non-), ignition immediately, high-temperature tail gas is discharged by the tail gas outlet 3 of combustion chamber, can be used for providing thermal source for minisize thermoelectric device or miniature hot photovoltaic system, also can be used as the high-temperature fuel gas of miniature propulsion system, produce thrust by follow-up jet pipe.

Enumerate an embodiment below: adopt the premixed combustion mode of hydrogen and air, the width of two preheating channels is 0.5mm, and the combustion chamber width is 1.0mm, and length is 10mm, and the bluff body cross sectional shape is the equilateral triangle of length of side 0.5mm.Solid material adopts resistant to elevated temperatures quartz glass, and hot rerum natura is as follows: density, thermal capacitance, thermal conductivity factor and normal emittance are respectively 2650kg/m ³, 750J/ (kgK), 1.05W/ (m ²K) and 0.92.Use general CFD software for calculation Fluent, and the detailed chemical reaction mechanism (comprising 19 reversible reactions and 13 kinds of constituent elements) of employing hydrogen and oxygen reaction, premix gas equivalent proportion has been carried out numerical simulation in the 0.4-1.0 scope, the result shows that blow-off limit of the present utility model is 2-4 a times of the dull and stereotyped burner of individual layer, as shown in Figure 3.Simultaneously, efficiency of combustion is also than the height of the dull and stereotyped burner of individual layer, (equivalent proportion is 0.5) as shown in Figure 4.These have proved that burner of the present utility model has the advantage of efficient steady combustion.

The above is preferred embodiment of the present utility model, but the utility model should not be confined to the disclosed content of this embodiment and accompanying drawing.So everyly do not break away from the equivalence of finishing under the spirit disclosed in the utility model or revise, all fall into the scope of the utility model protection.

Claims

1. a mini combustion device is characterized in that, this burner comprises bluff body (4), first, second preheating channel (5,6) and combustion chamber (7); First, second preheating channel (5,6) and combustion chamber (7) are plate; First, second preheating channel (5,6) is respectively equipped with gas access (1,2), and combustion chamber (7) are provided with tail gas outlet (3);

Bluff body (4) is installed in the porch of combustion chamber (7), the width W of bluff body (4) _bWidth W with combustion chamber (7) _cRatio be between 0.3 to 0.6; First, second preheating channel (5,6) is the L type, and is arranged in the upper and lower both sides of combustion chamber (7), and all is communicated with the inlet of combustion chamber (7).

2. mini combustion device according to claim 1 is characterized in that, the cross section of bluff body (4) is a triangle or cylindrical.

3. mini combustion device according to claim 1 and 2 is characterized in that, the surface of bluff body (4) is coated with catalyst.