A Venturi premixed swirl combustion test bench

Abstract

The invention discloses a swirl combustion test bench of Venturi premixing, comprising a nitrogen gas cylinder, a methane gas cylinder, an oxygen gas cylinder, a valve, a flow meter, a connecting pipe, a Venturi tube, a tee pipe, an elbow, a connecting pipe outside a swirl frame, a swirl burner, an igniter and a test bench, wherein the swirl burner comprises a combustion chamber, a burner front cover, a middle swirl frame, a burner rear cover, a screw and a nut, and the combustion chamber comprises a combustion chamber front section, a combustion chamber rear section, a flue, an igniter, an observation hole and a safety valve. Methane and nitrogen are evenly mixed through the Venturi tube, and oxygen and nitrogen are evenly mixed through the Venturi tube, and then enter the swirl burner tangentially for full combustion. By adjusting the valve opening of different gas cylinders, the flow rate of each gas can be adjusted and the mixing ratio of the gas can be changed. The invention can achieve uniform mixing of gases with different mixing ratios.

Description

Technical Field

[0001] The invention relates to gas premixed combustion, in particular to a venturi premixed swirl combustion test bench. Background Art

[0002] The venturi tube has many advantages such as simple structure, stability and durability, and has broad application prospects in various practical fields such as production and life, such as measuring flow and achieving gas mixing. The gas premixed by the three-way tube is not uniform enough. The direct combustion of the premixed gas may not be fully burned due to improper gas mixing ratio and insufficient mixing, which will affect the flame stability during the combustion process and may even cause the local mixed gas to reach the explosion concentration limit and cause a safety accident. Therefore, a venturi premixed swirl combustion test bench has become one of the technical keys in this field. Summary of the invention

[0003] The main technical problem solved by the present invention is to provide a Venturi premixed swirl combustion test bench, which can achieve sufficient mixing of methane and nitrogen, and nitrogen and oxygen in proportion. At the same time, the swirl burner can also achieve sufficient combustion of the mixed gas. The combustible components of many exhaust gases in industrial processes are very low, so methane and nitrogen are mixed to simulate low-concentration fuel gas of different concentrations (for the convenience of description, the "mixed gas of methane and nitrogen" hereinafter may also be referred to as "methane mixed gas"), and nitrogen and oxygen are mixed to simulate oxygen of different concentrations (for the convenience of description, the "mixed gas of oxygen and nitrogen" hereinafter may also be referred to as "oxygen mixed gas").

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0005] A swirl combustion test bench for venturi premixing, comprising a nitrogen cylinder a1, a methane cylinder b2, an oxygen cylinder c3, a nitrogen cylinder d4, a valve a5, a valve b6, a valve c7, a valve d8, a flow meter a9, a flow meter b10, a flow meter c11, a flow meter d12, a connecting pipe a13, a connecting pipe b14, a venturi tube a15, a venturi tube b16, a connecting pipe c17, a connecting pipe d18, a connecting pipe e19, a connecting pipe f20, a tee pipe a21, a tee pipe b22, a connecting pipe g 23, elbow a24, connecting pipe h25, elbow b26, elbow c27, connecting pipe a28 outside the swirl frame, connecting pipe i29, elbow d30, connecting pipe j31, elbow e32, elbow f33, connecting pipe b34 outside the swirl frame, swirl burner 35, connecting pipe k36, elbow g37, connecting pipe l38, elbow h39, connecting pipe c40 outside the swirl frame, connecting pipe m41, elbow i42, connecting pipe n43, elbow j44, connecting pipe d45 outside the swirl frame and experimental bench 46.

[0006] The nitrogen cylinder a1, valve a5, flow meter a9 and connecting pipe a13 are connected in sequence through flanges to form a first nitrogen gas pipeline, and the valve a5 can adjust the nitrogen gas flow; the methane cylinder b2, valve b6, flow meter b10 and connecting pipe c17 are connected in sequence through flanges to form a methane gas pipeline, and the valve b6 can adjust the methane gas flow.

[0007] The first nitrogen gas pipeline and the methane gas pipeline merge at the venturi tube a15, and the inlet of the venturi tube a15, the connecting pipe e19 and the tee pipe a21 are connected in sequence through flanges. The tee pipe a21 divides the mixed gas into two routes for transportation: one side outlet of the tee pipe a21, the connecting pipe g23, the elbow a24, the connecting pipe h25, the elbow b26, the elbow c27 and the connecting pipe a28 outside the swirl frame are connected in sequence through flanges and connected to the burner inlet a3531 of the swirl burner 35, forming a first transportation pipeline for the methane and nitrogen mixed gas; the other side outlet of the tee pipe a21, the connecting pipe i29, the elbow d30, the connecting pipe j31, the elbow e32, the elbow f33 and the connecting pipe b34 outside the swirl frame are connected in sequence through flanges and connected to the burner inlet c3533 of the swirl burner 35, forming a second transportation pipeline for the methane and nitrogen mixed gas.

[0008] The nitrogen cylinder d4, valve d8, flow meter d12 and connecting pipe b14 are connected in sequence through flanges to form a second nitrogen gas pipeline, and the valve d8 can adjust the nitrogen gas flow; the oxygen cylinder c3, valve c7, flow meter c11 and connecting pipe d18 are connected in sequence through flanges to form an oxygen gas pipeline, and the valve c7 can adjust the oxygen gas flow.

[0009] The second nitrogen gas pipeline merges with the oxygen gas pipeline at the venturi tube b16, and the inlet of the venturi tube b16, the connecting pipe f20 and the tee pipe b22 are connected in sequence through flanges. The tee pipe b22 divides the mixed gas into two routes for transportation: one side outlet of the tee pipe b22, the connecting pipe k36, the elbow g37, the connecting pipe l38, the elbow h39 and the connecting pipe c40 outside the swirl frame are connected in sequence through flanges and connected to the burner inlet b3532 of the swirl burner 35, forming a first transportation pipeline for the oxygen and nitrogen mixed gas; the other side outlet of the tee pipe b22, the connecting pipe m41, the elbow i42, the connecting pipe n43, the elbow j44 and the connecting pipe d45 outside the swirl frame are connected in sequence through flanges and connected to the burner inlet d3534 of the swirl burner 35, forming a second transportation pipeline for the oxygen and nitrogen mixed gas.

[0010] The venturi tube a15 includes an inlet straight pipe section 151, a tapered section 152, a throat 156, a gradually expanding section 157, an outlet straight pipe section 158, an external ejection hole 153, an annular pipe 154 and an internal ejection hole group 155. The internal ejection hole group 155 includes internal ejection holes a1551, internal ejection holes b1552, internal ejection holes c1553 and internal ejection holes d1554. When the mainstream gas nitrogen flows through the throat 156 of the venturi tube, due to the pressure difference, the external gas methane will be introduced into the nitrogen in the throat 156 of the venturi tube through the internal ejection holes a1551, internal ejection holes b1552, internal ejection holes c1553 and internal ejection holes d1554, thereby achieving mixing of the two gases, nitrogen and methane, and obtaining nitrogen and methane mixed gases with different methane concentrations to simulate industrial waste gases with different fuel gas concentrations.

[0011] The venturi tube b16 includes an inlet straight pipe section 161, a tapered section 162, a throat 166, a gradually expanding section 167, an outlet straight pipe section 168, an external ejection hole 163, an annular pipe 164 and an internal ejection hole group 165, wherein the internal ejection hole group 165 includes internal ejection holes a1651, b1652, c1653 and d1654. When the mainstream gas nitrogen flows through the throat 166 of the venturi tube, due to the pressure difference, the external gas oxygen will be introduced into the nitrogen in the throat 166 of the venturi tube through the internal ejection holes a1651, b1652, c1653 and d1654, thereby achieving a mixture of nitrogen and oxygen, and obtaining a mixed gas of nitrogen and oxygen with different oxygen concentrations, simulating combustion-supporting gases with different oxygen concentrations.

[0012] The swirl burner 35 includes a combustion chamber 351, a burner front cover 352, a middle swirl frame 353, a burner rear cover 354, a screw group 355 and a nut group 356, the screw group 355 includes screws a3551, screws b3552, screws c3553 and screws d3554, the nut group 356 includes nuts a3561, nuts b3562, nuts c3563 and nuts d3564, the middle swirl frame 353 includes burner inlets a3531, burner inlets b3532, burner inlets c3533, and burner inlets d3534. , burner inlet d3534, through hole a3535, through hole b3536, through hole c3537, through hole d3538 and middle round frame 3539, combustion chamber 351 includes combustion chamber front section 3511, combustion chamber rear section 3512, flue 3513, igniter 3514, observation hole 3515 and safety valve 3516, methane and oxygen enter combustion chamber 351 tangentially from burner inlet a3531, burner inlet b3532, burner inlet c3533 and burner inlet d3534 of middle swirl frame 353. Among them, observation hole 3515 is for observing the combustion of low-concentration fuel gas and oxygen, and safety valve 3516 is for protecting the experimental system.

[0013] The way that nitrogen and methane enter the burner is that nitrogen flows out from nitrogen cylinder a1, passes through valve a5, flow meter a9, connecting pipe a13 to venturi tube a15 in sequence, valve a5 can adjust the nitrogen gas flow, methane gas flows out from methane cylinder b2, passes through valve b6, flow meter b10 to venturi tube a15 in sequence, valve b6 can adjust the methane gas flow, the above two gases are fully mixed in venturi tube a15 and then flow out from the venturi tube, through connecting pipe a13 to venturi tube a15. The connecting pipe e19 to the tee pipe a21 is divided into two routes: one route passes through the connecting pipe g23, elbow a24, connecting pipe h25, elbow b26, elbow c27 and the connecting pipe a28 outside the swirl frame to the burner inlet a3531 of the swirl burner 35 in sequence; the other route passes through the connecting pipe i29, elbow d30, connecting pipe j31, elbow e32, elbow f33 and the connecting pipe b34 outside the swirl frame to the burner inlet c3533 of the swirl burner 35 in sequence.

[0014] The way nitrogen and oxygen enter the burner is that nitrogen flows out from nitrogen cylinder d4, passes through valve d8, flow meter d12 and connecting pipe b14 to venturi tube b16 in sequence. Valve d8 can adjust the nitrogen gas flow rate. Oxygen flows out from oxygen cylinder c3, passes through valve c7, flow meter c11 and connecting pipe d18 to venturi tube b16 in sequence. Valve c7 can adjust the oxygen gas flow rate. Nitrogen and oxygen are fully mixed in the venturi tube b16 and then discharged from the venturi tube b16. The water flows out from the inner pipe and is divided into two paths through the connecting pipe f20 to the tee pipe b22: one path passes through the connecting pipe k36, the elbow g37, the connecting pipe l38, the elbow h39 and the connecting pipe c40 outside the swirl frame to the burner inlet b3532 of the swirl burner 35; the other path passes through the connecting pipe m41, the elbow i42, the connecting pipe n43, the elbow j44 and the connecting pipe d45 outside the swirl frame to the burner inlet d3534 of the swirl burner 35.

[0015] Methane and oxygen are first mixed and then burned in the burner, wherein the mixed gas of nitrogen and methane enters the middle circular frame 3539 tangentially from the burner inlet a3531 and the burner inlet c3533 of the swirl burner 35, respectively, and the mixed gas of nitrogen and oxygen enters the middle circular frame 3539 tangentially from the burner inlet b3532 and the burner inlet d3534 of the swirl burner 35, respectively. The gas rotates and mixes in the middle circular frame 3539, and then enters the front section 3511 of the combustion chamber. After being ignited by the igniter 3514, the flame of the mixed gas with different methane and oxygen mixing ratios in the rear section 3512 of the combustion chamber can be observed through the observation hole 3515, and the smoke after combustion is discharged through the flue 3513. In order to ensure the safety of the combustion chamber 351 and the experimental system, a safety valve 3516 is installed on the rear section 3512 of the combustion chamber.

[0016] When conducting a premixed combustion experiment, first open the valve b6 of the methane cylinder b2, then open the valve a5 of the nitrogen cylinder a1, and adjust the opening of the valve a5 so that the nitrogen flow rate is m1. Through the induced effect of the venturi tube a15, the methane gas flow rate is m2 at this time, and the methane concentration of the methane mixed gas is m2 / (m1+m2); open the valve c7 of the oxygen cylinder c3, and then open the valve d8 of the nitrogen cylinder d4, and adjust the opening of the valve d8 so that the nitrogen flow rate is n1. Through the induced effect of the venturi tube b16, the oxygen flow rate is n2 at this time, and the oxygen concentration of the oxygen mixed gas is n2 / (n1+n2). Under this working condition, the mixing ratio of methane and oxygen entering the burner is (m1+m2):(n1+n2). If you want to conduct a combustion experiment in which the methane concentration is kept constant and the oxygen concentration is changed, you can maintain the concentration of the methane mixed gas at m2 / (m1+m2), adjust the opening of valve d8 so that the nitrogen flow rate is n11, and through the injection effect of the venturi tube b16, the oxygen flow rate is n21 at this time, and the oxygen concentration of the oxygen mixed gas is n21 / (n11+n21), and the mixing ratio of methane and oxygen entering the burner is (m1+m2):(n11+n21). Continue to change the opening of valve d8, change the nitrogen flow rate and the flow rate of oxygen injected by it, that is, change the oxygen concentration, and you can conduct experiments under multiple working conditions. If you want to keep the oxygen concentration constant and change the methane concentration in a combustion experiment In the combustion experiment, the oxygen concentration can be kept at n2 / (n1+n2). By adjusting the opening of valve a5, the nitrogen flow rate and the flow rate of the induced methane gas can be changed, that is, the concentration of the methane gas can be changed. For example, the opening of valve a5 is adjusted to make the nitrogen flow rate m11. Through the induced effect of venturi tube a15, the flow rate of methane gas is m21 at this time, and the methane concentration of the methane mixed gas is m21 / (m11+m21). The mixing ratio of methane and oxygen entering the burner is (m11+m21):(n1+n2). The opening of valve a5 is continued to be adjusted to change the nitrogen flow rate and the induced methane gas flow rate, that is, the concentration of the methane mixed gas can be changed, and experiments under multiple working conditions can be carried out. This experimental system can carry out combustion experiments with the methane concentration kept unchanged and the oxygen concentration changed, and can also carry out combustion experiments with the oxygen concentration kept unchanged and the methane concentration changed. It is easy to adjust and can carry out experiments under multiple working conditions.

[0017] The beneficial effects of the present invention are:

[0018] The invention discloses a swirl combustion test bench with a venturi premixing. Compared with the gas mixing of a conventional three-way pipe, the venturi premixing can realize the full mixing of methane and nitrogen, oxygen and nitrogen, and then conduct the full mixing combustion experiment of methane with different concentrations and oxygen with different concentrations, without the input of other power sources, and with low energy consumption. By using different valve openings, the mixing ratio of methane and oxygen can be adjusted, and the methane combustion under different working conditions can be observed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A three-dimensional front view of a Venturi premixed swirl combustion test bench according to the present invention;

[0020] Figure 2 A three-dimensional side view of a Venturi premixed swirl combustion test bench of the present invention;

[0021] Figure 3 A three-dimensional view of a venturi tube a of a venturi premixed swirl combustion test bench of the present invention;

[0022] Figure 4 It is a cross-sectional view of an annular pipe of a Venturi tube a of a Venturi premixed swirl combustion test bench of the present invention;

[0023] Figure 5 A three-dimensional view of a venturi tube b of a venturi premixed swirl combustion test bench of the present invention;

[0024] Figure 6 It is a cross-sectional view of an annular pipe of a Venturi tube b of a Venturi premixed swirl combustion test bench of the present invention;

[0025] Figure 7 A front three-dimensional view of a swirl burner of a Venturi premixed swirl combustion test bench of the present invention;

[0026] Figure 8 A rear three-dimensional view of a swirl burner of a Venturi premixed swirl combustion test bench according to the present invention;

[0027] Fig. 9 A cross-sectional view of a middle swirl frame of a swirl burner of a venturi premixed swirl combustion test bench according to the present invention;

[0028] Fig.10 A front three-dimensional view of a combustion chamber of a swirl burner of a venturi premixed swirl combustion test bench according to the present invention;

[0029] Fig.11 This is a three-dimensional rear view of the combustion chamber of a swirl burner of a Venturi premixed swirl combustion test bench according to the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0031] The present invention discloses a swirl combustion test bench for venturi premixing, comprising a nitrogen gas cylinder a1, a methane gas cylinder b2, an oxygen gas cylinder c3, a nitrogen gas cylinder d4, a valve a5, a valve b6, a valve c7, a valve d8, a flow meter a9, a flow meter b10, a flow meter c11, a flow meter d12, a connecting pipe a13, a connecting pipe b14, a venturi tube a15, a venturi tube b16, a connecting pipe c17, a connecting pipe d18, a connecting pipe e19, a connecting pipe f20, a tee pipe a21, a tee pipe b22, a connecting pipe g23, an elbow a24, a connecting pipe h25, an elbow b26, an elbow c27, a connecting pipe a28 outside a swirl frame, a connecting pipe i29, elbow d30, connecting pipe j31, elbow e32, elbow f33, connecting pipe b34 outside the swirl frame, swirl burner 35, connecting pipe k36, elbow g37, connecting pipe l38, elbow h39, connecting pipe c40 outside the swirl frame, connecting pipe m41, elbow i42, connecting pipe n43, elbow j44, connecting pipe d45 outside the swirl frame and experimental table 46; Venturi tube a15 includes an inlet straight pipe section 151, a tapered section 152, a throat 156, a gradually expanding section 157, an outlet straight pipe section 158, an external ejection hole 153, an annular pipe 154 and an internal ejection hole group 155, and the internal ejection hole group 155 includes the internal ejection hole a15 51, inner ejection hole b1552, inner ejection hole c1553 and inner ejection hole d1554; the venturi tube b16 includes an inlet straight pipe section 161, a tapered section 162, a throat 166, a gradually expanding section 167, an outlet straight pipe section 168, an outer ejection hole 163, an annular pipe 164 and an inner ejection hole group 165, the inner ejection hole group 165 includes an inner ejection hole a1651, an inner ejection hole b1652, an inner ejection hole c1653 and an inner ejection hole d1654; the swirl burner 35 includes a combustion chamber 351, a burner front cover 352, a middle swirl frame 353, a burner rear cover 354, a screw group 355 and a nut group 356, the screw group 355 includes a screw a 3551, screw b3552, screw c3553 and screw d3554, the nut group 356 includes nut a3561, nut b3562, nut c3563 and nut d3564, the middle swirl frame 353 includes burner inlet a3531, burner inlet b3532, burner inlet c3533, burner inlet d3534, through hole a3535, through hole b3536, through hole c3537, through hole d3538 and a middle circular frame 3539, the combustion chamber 351 includes the combustion chamber front section 3511, the combustion chamber rear section 3512, the flue 3513, the igniter 3514, the observation hole 3515 and the safety valve 3516.

[0032] Reference Figure 1 and Figure 2The nitrogen cylinder a1, valve a5, flow meter a9 and connecting pipe a13 are connected in sequence through flanges to form a first nitrogen gas pipeline; the methane cylinder b2, valve b6, flow meter b10 and connecting pipe c17 are connected in sequence through flanges to form a methane gas pipeline, and the first nitrogen gas pipeline and the methane gas pipeline merge at the venturi tube a15. The inlets of the venturi tube a15, the connecting pipe e19 and the tee pipe a21 are connected in sequence through flanges, and the tee pipe a21 divides the nitrogen and methane mixed gas into two routes for transportation: one side outlet of the tee pipe a21, the connecting pipe g23, the elbow a24, the connecting pipe h25, the elbow b26, the elbow c27 and the connecting pipe a28 outside the swirl frame are connected in sequence through flanges, connected to the burner inlet a3531 of the swirl burner 35, forming a first transportation pipeline for the methane and nitrogen mixed gas; the other side outlet of the tee pipe a21, the connecting pipe i29, the elbow d30, the connecting pipe j31, the elbow e32, the elbow f33 and the connecting pipe b34 outside the swirl frame are connected in sequence through flanges, connected to the burner inlet c3533 of the swirl burner 35, forming a second transportation pipeline for the methane and nitrogen mixed gas. The nitrogen cylinder d4, valve d8, flow meter d12 and connecting pipe b14 are connected in sequence through flanges to form a second nitrogen gas pipeline. The oxygen cylinder c3, valve c7, flow meter c11 and connecting pipe d18 are connected in sequence through flanges to form an oxygen gas pipeline. The second nitrogen gas pipeline and the oxygen gas pipeline merge at the venturi tube b16. The outlet of the venturi tube b16, the connecting pipe f20 and the inlet of the tee pipe b22 are connected in sequence through flanges, and the tee pipe b22 divides the oxygen and nitrogen mixed gas into two routes for transportation: one side outlet of the tee pipe b22, the connecting pipe k36, the elbow g37, the connecting pipe l38, the elbow h39 and the connecting pipe c40 outside the swirl frame are connected in sequence through flanges, connected to the burner inlet b3532 of the swirl burner 35, forming a first transportation pipeline for the oxygen and nitrogen mixed gas; the other side outlet of the tee pipe b22, the connecting pipe m41, the elbow i42, the connecting pipe n43, the elbow j44 and the connecting pipe d45 outside the swirl frame are connected in sequence through flanges, connected to the burner inlet d3534 of the swirl burner 35, forming a second transportation pipeline for the oxygen and nitrogen mixed gas.

[0033] like Figure 3 and Figure 4The venturi tube a15 includes an inlet straight pipe section 151, a tapering section 152, a throat 156, a gradually expanding section 157, an outlet straight pipe section 158, an external ejection hole 153, an annular pipe 154 and an internal ejection hole group 155. The internal ejection hole group 155 includes an internal ejection hole a1551, an internal ejection hole b1552, an internal ejection hole c1553 and an internal ejection hole d1554. Nitrogen enters from the inlet straight pipe section 151 of the venturi tube, passes through the tapered section 152 and the throat 156 in sequence, methane gas enters the annular pipe 154 from the outer ejection hole 153 of the venturi tube, and then enters the throat 156 of the venturi tube through the inner ejection hole a1551, the inner ejection hole b1552, the inner ejection hole c1553 and the inner ejection hole d1554 to evenly merge with nitrogen, and the nitrogen and methane mixed gas passes through the gradually expanding section 157 and the outlet straight pipe section 158 in sequence. In the venturi tube, the nitrogen gas flows faster and the pressure decreases through the tapered section, forming a low-pressure area in the throat, and the pressure of the methane gas is higher than the throat pressure. Due to the pressure difference, the methane gas enters the throat of the venturi tube and merges with the nitrogen, and then fully mixes in the gradually expanding section, so that the two gases can be evenly and fully mixed, and a mixed gas of methane and nitrogen with different methane concentrations is obtained to simulate industrial waste gas with different combustible gas concentrations.

[0034] like Figure 5 and Figure 6 The venturi tube b16 includes an inlet straight pipe section 161, a tapered section 162, a throat 166, a gradually expanding section 167, an outlet straight pipe section 168, an external ejection hole 163, an annular pipe 164 and an internal ejection hole group 165. The internal ejection hole group 165 includes an internal ejection hole a1651, an internal ejection hole b1652, an internal ejection hole c1653 and an internal ejection hole d1654. Nitrogen enters from the inlet straight pipe section 161 of the venturi tube, passes through the tapered section 162 and the throat 166 in sequence, oxygen enters the annular pipe 164 from the outer ejection hole 163 of the venturi tube, and then enters the throat 166 of the venturi tube through the inner ejection hole a1651, the inner ejection hole b1652, the inner ejection hole c1653 and the inner ejection hole d1654 to evenly merge with nitrogen, and the nitrogen and oxygen mixed gas then passes through the gradually expanding section 167 and the outlet straight pipe section 168 in sequence. In the venturi tube, the nitrogen speed increases and the pressure decreases through the tapered section, forming a low-pressure area in the throat, and the pressure of oxygen is higher than the throat pressure. Due to the pressure difference, oxygen enters the throat of the venturi tube and merges with nitrogen, and then is fully mixed in the gradually expanding section, so that the nitrogen and oxygen gases can be evenly and fully mixed to obtain mixed gases with different oxygen concentrations.

[0035] like Figure 7 and Figure 8The swirl burner 35 includes a swirl burner tube 351, a burner front cover 352, a middle swirl frame 353, a burner rear cover 354, a screw group 355 and a nut group 356. The screw group 355 includes screw a3551, screw b3552, screw c3553 and screw d3554. The nut group 356 includes nut a3561, nut b3562, nut c3563 and nut d3564. Fig. 9 The middle swirl frame 353 of the swirl burner 35 includes a burner inlet a3531, a burner inlet b3532, a burner inlet c3533, a burner inlet d3534, a through hole a3535, a through hole b3536, a through hole c3537, a through hole d3538 and a middle circular frame 3539. Fig.10 and Fig.11 The combustion chamber 351 includes a combustion chamber front section 3511, a combustion chamber rear section 3512, a flue 3513, an igniter 3514, an observation hole 3515 and a safety valve 3516. The mixed gas enters the middle circular frame 353 tangentially from the burner inlet a3531, the burner inlet b3532, the burner inlet c3533 and the burner inlet d3534, and the gas flow direction is shown by the arrow in the figure; in the middle circular frame 353, the gas rotates and mixes along the direction shown by the arrow.

[0036] As a preferred embodiment of the present invention, Figure 1 and Figure 2As shown, the first nitrogen gas flows out from the nitrogen cylinder a1, passes through the valve a5, the flow meter a9 and the connecting pipe a13 to the venturi tube a15 in sequence, and the methane gas flows out from the methane cylinder b2, passes through the valve b6 and the flow meter b10 to the venturi tube a15 in sequence. The above two gases are fully mixed in the venturi tube a15 and then flow out from the venturi tube a15, and are divided into two paths through the connecting pipe e19 to the tee a21. One path passes through the connecting pipe g23, the elbow a24, the connecting pipe h25, the elbow b26, the elbow c27 and the connecting pipe a28 outside the swirl frame in sequence to the burner inlet a3531 of the swirl burner 35, and the other path passes through the connecting pipe i29, the elbow d30, the connecting pipe j31, the elbow e32, the elbow f33 and the connecting pipe b34 outside the swirl frame in sequence to the burner inlet c3 of the swirl burner 35. 533; The second nitrogen gas flows out from the nitrogen cylinder d4, passes through the valve d8, the flow meter d12 and the connecting pipe b14 to the venturi tube b16 in sequence, and the oxygen flows out from the oxygen cylinder c3, passes through the valve c7, the flow meter c11 and the connecting pipe d18 to the venturi tube b16 in sequence. The above two gases are fully mixed in the venturi tube b16 and then flow out from the venturi tube b16, and are divided into two paths through the connecting pipe f20 to the tee pipe b22. One path passes through the connecting pipe k36, the elbow g37, the connecting pipe l38, the elbow h39 and the connecting pipe c40 outside the swirl frame to the burner inlet b3532 of the swirl burner 35 in sequence, and the other path passes through the connecting pipe m41, the elbow i42, the connecting pipe n43, the elbow j44 and the connecting pipe d45 outside the swirl frame to the burner inlet d3534 of the swirl burner 35 in sequence. In the swirl burner 35, as Figure 7 , Figure 8 and Fig. 9 The mixed gas enters the middle circular frame 3539 from the burner inlet a3531, the burner inlet b3532, the burner inlet c3533 and the burner inlet d3534 respectively. The gas flow direction is shown by the arrow in the figure. The mixed gas rotates and mixes in the direction shown by the arrow in the middle circular frame 3539, and then enters the front section 3511 of the combustion chamber. After being ignited by the igniter 3514, the flame of the mixed gas with different methane and oxygen mixing ratios in the rear section 3512 of the combustion chamber can be observed through the observation hole 3515, and the smoke after combustion is discharged through the flue 3513. In order to ensure the safety of the combustion chamber 351 and the safety of the experimental system, a safety valve 3516 is installed in the rear section 3512 of the combustion chamber.

[0037] When conducting a premixed combustion experiment, first open the valve b6 of the methane cylinder b2, then open the valve a5 of the nitrogen cylinder a1, and adjust the opening of the valve a5 so that the nitrogen flow rate is m1. Through the induced effect of the venturi tube a15, the methane gas flow rate is m2 at this time, and the methane concentration of the methane mixed gas is m2 / (m1+m2); open the valve c7 of the oxygen cylinder c3, and then open the valve d8 of the nitrogen cylinder d4, and adjust the opening of the valve d8 so that the nitrogen flow rate is n1. Through the induced effect of the venturi tube b16, the oxygen flow rate is n2 at this time, and the oxygen concentration of the oxygen mixed gas is n2 / (n1+n2). Under this working condition, the mixing ratio of methane and oxygen entering the burner is (m1+m2):(n1+n2). If you want to conduct a combustion experiment in which the methane concentration is kept constant and the oxygen concentration is changed, you can maintain the concentration of the methane mixed gas at m2 / (m1+m2), adjust the opening of valve d8 so that the nitrogen flow rate is n11, and through the injection effect of the venturi tube b16, the oxygen flow rate is n21 at this time, and the oxygen concentration of the oxygen mixed gas is n21 / (n11+n21), and the mixing ratio of methane and oxygen entering the burner is (m1+m2):(n11+n21). Continue to change the opening of valve d8, change the nitrogen flow rate and the flow rate of oxygen injected by it, that is, change the oxygen concentration, and you can conduct experiments under multiple working conditions. If you want to keep the oxygen concentration constant and change the methane concentration in a combustion experiment In the combustion experiment, the oxygen concentration can be kept at n2 / (n1+n2). By adjusting the opening of valve a5, the nitrogen flow rate and the flow rate of the induced methane gas can be changed, that is, the concentration of the methane gas can be changed. For example, the opening of valve a5 is adjusted to make the nitrogen flow rate m11. Through the induced effect of venturi tube a15, the flow rate of methane gas is m21 at this time, and the methane concentration of the methane mixed gas is m21 / (m11+m21). The mixing ratio of methane and oxygen entering the burner is (m11+m21):(n1+n2). The opening of valve a5 is continued to be adjusted to change the nitrogen flow rate and the induced methane gas flow rate, that is, the concentration of the methane mixed gas can be changed, and experiments under multiple working conditions can be carried out. This experimental system can carry out combustion experiments with the methane concentration kept unchanged and the oxygen concentration changed, and can also carry out combustion experiments with the oxygen concentration kept unchanged and the methane concentration changed. It is easy to adjust and can carry out experiments under multiple working conditions.

[0038] For further explanation, specific numbers are used to illustrate the adjustment of the ratio of methane and oxygen to keep the methane concentration unchanged and change the oxygen concentration in a combustion experiment as a specific example: first open the valve b6 of the methane cylinder b2, then open the valve a5 of the nitrogen cylinder a1, and adjust the opening of the valve a5 so that the nitrogen flow rate is 1.00m 3 ·h -1 , through the venturi tube a15 injection, the flow rate of methane gas is 0.25m 3 ·h-1 , the concentration of the methane mixed gas is 20%; open the valve c7 of the oxygen cylinder c3, then open the valve d8 of the nitrogen cylinder d4, and adjust the opening of the valve d8 so that the nitrogen flow rate is 2.00m 3 ·h -1 , through the venturi tube b16, the oxygen flow rate is 0.50m 3 ·h -1 , the concentration of oxygen mixed gas is 20%. Under this condition, the mixing ratio of methane and oxygen entering the burner is 1:2. Keep the concentration of methane mixed gas at 20%, and adjust the opening of valve d8 so that the nitrogen flow rate is 1.50m 3 ·h -1 , through the venturi tube b16, the oxygen flow rate is 0.35m 3 ·h -1 , the concentration of the oxygen mixed gas is 18.9%, and the mixing ratio of methane and oxygen entering the burner is 1:1.48. Keep the concentration of the methane mixed gas at 20%, and continue to adjust the opening of valve d8 so that the nitrogen flow rate is 1.20m 3 ·h -1 , through the venturi tube b16, the oxygen flow rate is 0.26m 3 ·h -1 , the concentration of oxygen mixed gas is 17.8%, and the mixing ratio of methane and oxygen entering the burner is 1:1.17. Therefore, continuing to adjust the opening of valve d8 can carry out experiments under multiple working conditions.

[0039] In summary, the present invention achieves sufficient and uniform mixing of two gases through the venturi tube, which can make the combustion more stable; the combustion of the premixed gas in the swirl burner can achieve sufficient combustion.

Claims

1. A Venturi premixed swirl combustion test bench, characterized in that: The invention comprises a nitrogen cylinder a (1), a methane cylinder b (2), an oxygen cylinder c (3), a nitrogen cylinder d (4), a valve a (5), a valve b (6), a valve c (7), a valve d (8), a flow meter a (9), a flow meter b (10), a flow meter c (11), a flow meter d (12), a connecting pipe a (13), a connecting pipe b (14), a venturi tube a (15), a venturi tube b (16), a connecting pipe c (17), a connecting pipe d (18), a connecting pipe e (19), a connecting pipe f (20), a tee a (21), a tee b (22), a connecting pipe g (23), an elbow a (24), a connecting pipe h (25), an elbow b (26), an elbow c (27), and an outer swirl frame. A connecting pipe a (28), a connecting pipeline i (29), an elbow d (30), a connecting pipeline j (31), an elbow e (32), an elbow f (33), a connecting pipe b (34) outside the swirl frame, a swirl burner (35), a connecting pipeline k (36), an elbow g (37), a connecting pipeline l (38), an elbow h (39), a connecting pipe c (40) outside the swirl frame, a connecting pipeline m (41), an elbow i (42), a connecting pipeline n (43), an elbow j (44), a connecting pipe d (45) outside the swirl frame and a laboratory table (46); the nitrogen gas cylinder a (1), the valve a (5), the flow meter a (9) and the connecting pipeline a (13) are connected in sequence through flanges to form a first nitrogen gas pipeline; the methane gas cylinder b (2), the valve The gate b (6), the flow meter b (10) and the connecting pipe c (17) are connected in sequence through flanges to form a methane gas pipeline; the first nitrogen gas pipeline is connected to the methane gas pipeline at the venturi tube a (15); the inlet of the venturi tube a (15), the connecting pipe e (19) and the tee pipe a (21) are connected in sequence through flanges; the tee pipe a (21) divides the methane and nitrogen mixed gas into two routes for transmission: one side outlet of the tee pipe a (21), the connecting pipe g (23), the elbow a (24), the connecting pipe h (25), the elbow b (26), the elbow c (27) and the connecting pipe a (28) outside the swirl frame are connected in sequence through flanges and connected to the burner inlet a (3531) of the swirl burner (35) to form a methane gas pipeline. and a first delivery pipeline for a mixed gas of methane and nitrogen; the other side outlet of the tee pipe a (21), the connecting pipeline i (29), the elbow d (30), the connecting pipeline j (31), the elbow e (32), the elbow f (33) and the connecting pipe b (34) outside the swirl frame are connected in sequence through flanges and connected to the burner inlet c (3533) of the swirl burner (35) to form a second delivery pipeline for a mixed gas of methane and nitrogen; the nitrogen gas cylinder d (4), the valve d (8), the flow meter d (12) and the connecting pipeline b (14) are connected in sequence through flanges to form a second nitrogen gas pipeline; the oxygen gas cylinder c (3), the valve c (7), the flow meter c (11) and the connecting pipeline d (18) are connected in sequence through flanges to form an oxygen gas pipeline;The second nitrogen gas pipeline is connected to the oxygen gas pipeline at the venturi tube b (16), and the inlet of the venturi tube b (16), the connecting pipe f (20) and the three-way pipe b (22) are connected in sequence through flanges. The three-way pipe b (22) divides the oxygen and nitrogen mixed gas into two routes for transmission: one side outlet of the three-way pipe b (22), the connecting pipe k (36), the elbow g (37), the connecting pipe l (38), the elbow h (39) and the connecting pipe c (40) outside the swirl frame are connected in sequence through flanges. The other side outlet of the three-way pipe b (22), the connecting pipe m (41), the elbow i (42), the connecting pipe n (43), the elbow j (44) and the connecting pipe d (45) outside the swirl frame are sequentially connected through flanges and connected to the burner inlet d (3534) of the swirl burner (35) to form a second conveying pipeline for the mixed gas of oxygen and nitrogen.

2. A Venturi premixed swirl combustion test bench according to claim 1, characterized in that: The venturi tube a (15) comprises an inlet straight pipe section (151), a tapered section (152), a throat (156), a gradually expanding section (157), an outlet straight pipe section (158), an external ejection hole (153), an annular pipe (154) and an internal ejection hole group (155); the internal ejection hole group (155) comprises an internal ejection hole a (1551), an internal ejection hole b (1552), an internal ejection hole c (1553) and an internal ejection hole d (1554); when the mainstream gas nitrogen flows through the throat section (156) of the venturi tube, due to the pressure difference, the external gas methane is introduced into the nitrogen in the throat section (156) of the venturi tube through the internal ejection hole a (1551), the internal ejection hole b (1552), the internal ejection hole c (1553) and the internal ejection hole d (1554), thereby achieving mixing of the two gases, nitrogen and methane.

3. The Venturi premixed swirl combustion test bench according to claim 1, characterized in that: The venturi tube b (16) comprises an inlet straight pipe section (161), a tapered section (162), a throat (166), a gradually expanding section (167), an outlet straight pipe section (168), an external ejection hole (163), an annular pipe (164) and an internal ejection hole group (165). The internal ejection hole group (165) comprises an internal ejection hole a (1651), an internal ejection hole b (1652), an internal ejection hole c (1653) and an internal ejection hole d (1654). When the mainstream gas nitrogen flows through the throat section (166) of the venturi tube, due to the pressure difference, the external gas oxygen is introduced into the nitrogen in the throat section (166) of the venturi tube through the internal ejection hole a (1651), the internal ejection hole b (1652), the internal ejection hole c (1653) and the internal ejection hole d (1654), thereby achieving mixing of the two gases of nitrogen and oxygen.

4. The Venturi premixed swirl combustion test bench according to claim 1, characterized in that: The swirl burner (35) comprises a combustion chamber (351), a burner front cover (352), a middle swirl frame (353), a burner rear cover (354), a screw group (355) and a nut group (356), wherein the screw group (355) comprises a screw a (3551), a screw b (3552), a screw c (3553) and a screw d (3554), the nut group (356) comprises a nut a (3561), a nut b (3562), a nut c (3563) and a nut d (3564), and the middle swirl frame (353) comprises a burner inlet a (3531), a burner inlet b (3532), a burner inlet c (3533) and a burner inlet d (3534). 3), burner inlet d (3534), through hole a (3535), through hole b (3536), through hole c (3537), through hole d (3538) and a middle circular frame (3539), the combustion chamber (351) includes a combustion chamber front section (3511), a combustion chamber rear section (3512), a flue (3513), an igniter (3514), an observation hole (3515) and a safety valve (3516), and methane and oxygen enter the combustion chamber (351) tangentially from the burner inlet a (3531), the burner inlet b (3532), the burner inlet c (3533) and the burner inlet d (3534) of the middle swirl frame (353).

5. The Venturi premixed swirl combustion test bench according to claim 1, characterized in that: Methane and oxygen are first mixed and then burned in the burner, wherein the mixed gas of nitrogen and methane enters the middle circular frame (3539) tangentially from the burner inlet a (3531) and the burner inlet c (3533) of the swirl burner (35), and the mixed gas of nitrogen and oxygen enters the middle circular frame (3539) tangentially from the burner inlet b (3532) and the burner inlet d (3534) of the swirl burner (35), respectively. The gas rotates and mixes in the middle circular frame (3539) and then enters the front section (3511) of the combustion chamber. After being ignited by the igniter (3514), the flame of the mixed gas with different methane and oxygen mixing ratios in the rear section (3512) of the combustion chamber can be observed through the observation hole (3515), and the smoke after combustion is discharged through the flue (3513).

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