CN110705110B - Stress and strain calculation method for high-pressure packing box of large reciprocating compressor - Google Patents
Stress and strain calculation method for high-pressure packing box of large reciprocating compressor Download PDFInfo
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Abstract
The invention discloses a stress calculation method for a high-pressure packing box of a large reciprocating compressor, which can be used for designing and calculating the high-pressure packing box with a piston rod sealed by polytetrafluoroethylene or polyether-ether-ketone packing and with exhaust pressure up to 30 MPa. The design calculation step comprises the steps of establishing a stress model analysis of the stuffing box; analyzing dangerous sections of stress and strain of the stuffing box; calculating the maximum stress and the maximum strain of the stuffing box; calculating the fatigue strength of the stuffing box and meeting the rigidity requirement; through the process, the high-pressure packing assembly has enough use strength and rigidity, and the packing sealing reliability under high temperature and high pressure is improved.
Description
Technical Field
The invention relates to the technical field of high-pressure reciprocating compressors, in particular to a stress and strain calculation method for a high-pressure packing box of a large reciprocating compressor.
Background
When the large-scale high-pressure reciprocating compressor is sealed by polytetrafluoroethylene or polyether-ether-ketone packing, the working pressure of a packing assembly of a piston rod can reach 30MPa, at present, no mature and reliable method for calculating the stress and strain of a packing box exists, and effective sealing of the packing is difficult to realize. The stress and strain calculation of the stuffing box is very important for the safety and effectiveness of the compressor under the working conditions of high temperature and high pressure, wherein the working medium of the compressor is flammable and explosive gas. For the compressors (such as a hydrogen compressor with the exhaust pressure of 18MPa and a circulating hydrogen compressor with the exhaust pressure of 20.9 MPa) which are in flammable and explosive gas and under the high-temperature and high-pressure working condition, the stress and strain calculation method of the high-pressure packing box can ensure that the high-pressure packing box has enough use strength and rigidity, avoid the potential safety hazards of fatigue damage and sealing failure of the packing assembly, and improve the reliability and the safety of packing sealing.
SUMMERY OF THE UTILITY MODEL
The invention aims to: a mechanical analysis model is established and stress analysis calculation is carried out, and the stress and strain calculation method of the high-pressure packing box of the large reciprocating compressor is provided.
In order to achieve the purpose, the invention adopts the following technical scheme:
the stress and strain calculating method of the high-pressure stuffing box of the large reciprocating compressor comprises the following steps:
(1) Establishing a stress model analysis of the stuffing box:
(1.1) the working pressure of the high-pressure packing part is p;
(1.2) the pretightening force of the packing assembly bolt is F0, the lateral acting force is F1, the total thickness H of the packing box, the depth H1 of the sealing groove, the diameter D of the sealing groove, and the diameter D1 of the piston rod passing through part of the circular hole;
(1.3) by analyzing the stress of each stuffing box, further analyzing, the stress of the stuffing box is that the circular ring is pressed, the pressure of the circular ring seal is q equal to the seal working pressure p of the stuffing, the outer diameter dimension of the circular ring is defined as D =2b, the inner diameter dimension is defined as D1=2a, and the thickness of the circular ring is defined as t = H-H1;
(2) Analysis of dangerous sections of stuffing box stress and strain:
(2.1) in order to ensure the sealing of the polytetrafluoroethylene or polyether ether ketone packing, the packing box must be designed into a rigid reinforced connecting plate, when the high-pressure packing assembly works, the deformation (strain) of a compressed ring is omega, the bending stress sigma theta generated by the ring plate is extremely small, the internal stress sigma r in the diameter direction is extremely small, a coordinate axis is established by taking the center of the ring as an origin, and the distance from the center of the ring is r;
(2.2) maximum deformation and maximum bending stress occur at the edge of the annular plate r = a, here the dangerous section;
(3) Calculating the maximum stress and the maximum strain of the stuffing box:
is defined as
The maximum bending stress σ max and the maximum deformation ω max are formulated as:
σmax＝(σθ)k＝K＝αm 2 q (1)
wherein
E is the elastic modulus of the material, and the elastic modulus of stainless steel is 205000Mpa;
correction coefficients of alpha and beta related to stress according to K value;
(5) Calculating the fatigue strength of the stuffing box and meeting the rigidity requirement:
(4.1) when the high-pressure packing works, working pressure is periodically changed according to a crank angle of 0-360 degrees, the stress load of a circular ring plate of a packing box is also periodic, the suction pressure of a compressor is defined as PS, the exhaust pressure is defined as PD, the maximum bending stress and the minimum bending stress at the dangerous section of the packing circular ring are respectively sigma max and sigma mi n according to the formula (1), the average bending stress sigma m and the stress amplitude sigma a are defined, and the calculation formula is as follows:
σa＝ (4)
(4.2) as fatigue Strength
The limit is sigma-1, and the calculation formula is as follows:
wherein
Defining the equivalent coefficient; sigma B Defined as tensile strength; when stainless steel is ground and processed under the action of tension-compression circulating stress, the equivalent coefficient of the stainless steel is greater or less than>
Taking 0.35; the tensile strength of the stainless steel is 780Mpa; calculating a fatigue strength limit sigma-1 =273Mpa according to a formula (5);
(4.3) defining the safety coefficient of the fatigue strength of the inner ring part of the high-pressure filler as n under the action of bending stress, and calculating the formula as follows:
wherein (k) σD ) Defining the amplitude comprehensive average coefficient of the bending stress; integrated average coefficient (k) σD ) The magnitude of the stress is related to the stress concentration, the size of the inner ring of the packing and the surface roughness according to the stress condition (k) σD ) The value is 3.1;
(4.4) according to the formula (6), the safety coefficient of the fatigue strength is n, and the calculation formula is as follows:
defining the maximum allowable safety factor when the stuffing box works as [ n ], wherein for a high-pressure compressor, [ n ] =2;
the safety coefficient of the fatigue strength of the high-pressure stuffing box calculated according to the formula (7) is n is more than or equal to [ n ], namely n is more than or equal to 2;
(4.5) calculating the maximum deformation amount omega max of the inner ring part of the high-pressure stuffing box according to the formula (2), wherein for the high-pressure compressor, the omega max is less than or equal to 0.003 for ensuring reliable sealing.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
in the invention, by using the method, the stress calculation can be carried out on the stuffing box under the known conditions of the structural size of the stuffing box, the material performance parameters, the air inlet pressure and the air exhaust pressure of the compressor; and the stress safety coefficient can be properly adjusted according to the special working characteristics of the high-pressure compressor packing, such as stress concentration, air inlet and exhaust pressure change, unit vibration conditions and the like, so that the high-pressure packing box is ensured to have enough use strength and rigidity.
Drawings
FIG. 1 shows a flow diagram provided in accordance with an embodiment of the present invention;
FIG. 2 illustrates an overall force diagram of a packing assembly provided in accordance with an embodiment of the present invention;
figure 3 illustrates a diagram of respective stuffing boxes provided according to an embodiment of the present invention;
FIG. 4 illustrates a diagram of a portion of a ring provided in accordance with an embodiment of the present invention;
FIG. 5 illustrates stress and strain maps provided in accordance with an embodiment of the present invention;
FIG. 6 illustrates a K value table provided in accordance with an embodiment of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows: referring to fig. 1-5 and table 6, the present invention provides a solution: the stress and strain calculating method for the high-pressure stuffing box of the large reciprocating compressor comprises the following steps:
(1) Establishing a stress model analysis of the stuffing box:
(1.1) the working pressure of the high pressure packing element is p and the entire packing assembly is attempted to be shown in FIG. 2;
(1.2) the pretightening force of the bolt of the packing assembly is F0, the lateral acting force is F1, the total thickness of the packing boxes is H, the depth of a sealing groove is H1, the diameter of the sealing groove is D, the diameter of a piston rod passing through part of circular holes is D1, and the stress diagram of each packing box is shown in FIG. 3;
(1.3) by analyzing the stress of each stuffing box, further analyzing, the stress of the stuffing box is that the circular ring is pressed, the pressure of the circular ring seal is q equal to the seal working pressure p of the stuffing, the outer diameter dimension of the circular ring is defined as D =2b, the inner diameter dimension of the circular ring is defined as D1=2a, the thickness of the circular ring is defined as t = H-H1, and the partial stress of the circular ring is shown in figure 4;
(2) Analysis of dangerous sections of stuffing box stress and strain:
(2.1) in order to ensure the sealing of the polytetrafluoroethylene or polyether-ether-ketone packing, the packing box must be designed into a rigid reinforced connecting plate, when the high-pressure packing assembly works, the deformation (strain) of a compressed ring is omega, the bending stress sigma theta generated by the ring plate is extremely small in the internal stress sigma r in the diameter direction, a coordinate axis is established by taking the center of the ring as an original point, the distance from the center of the ring is r, and the stress and strain diagram is shown in figure 5 at the moment;
(2.2) maximum deformation and maximum bending stress occur at the edge of the annular plate r = a, here the dangerous section;
(3) Calculating the maximum stress and the maximum strain of the stuffing box:
is defined as
The maximum bending stress σ max and the maximum deformation ω max are formulated as:
σmax＝(σθ)k＝K＝αm 2 q (1)
wherein
E is the elastic modulus of the material, and the elastic modulus of stainless steel is 205000Mpa;
the correction coefficients of alpha and beta relative to stress according to K value are shown in Table 6;
(6) Calculating the fatigue strength of the stuffing box and meeting the rigidity requirement:
(4.1) when the high-pressure packing works, the working pressure is periodically changed according to the crank angle of 0-360 degrees, the stress load of a circular ring plate of the packing box is also periodic, the suction pressure of a compressor is defined as PS, the exhaust pressure is defined as PD, the maximum and minimum bending stresses at the dangerous section of the packing circular ring are respectively sigma max and sigma min according to the formula (1), the average bending stress sigma m and the stress amplitude sigma a are defined, and the calculation formula is as follows:
σa＝ (4)
(4.2) as fatigue Strength
The limit is sigma-1, and the calculation formula is as follows:
wherein
Defined as an equivalent coefficient; sigma B Defined as tensile strength; when stainless steel is ground and processed under the action of tension-compression circulating stress, the equivalent coefficient of the stainless steel is greater or less than>
Taking 0.35; the tensile strength of the stainless steel is 780Mpa; calculating the fatigue strength limit sigma-1 =273mpa according to the formula (5);
(4.3) defining the safety coefficient of the fatigue strength of the inner ring part of the high-pressure filler as n under the action of bending stress, and calculating the formula as follows:
wherein (k) σD ) Defining the amplitude comprehensive average coefficient of the bending stress; integrated average coefficient (k) σD ) The magnitude of the stress is related to the stress concentration, the size of the inner ring of the packing and the surface roughness according to the stress condition (k) σD ) Taking the value of 3.1;
(4.4) according to the formula (6), the safety coefficient of the fatigue strength is n, and the calculation formula is as follows:
defining the maximum allowable safety factor when the stuffing box works as [ n ], wherein for a high-pressure compressor, [ n ] =2;
the safety coefficient of the fatigue strength of the high-pressure stuffing box calculated according to the formula (7) is n which is more than or equal to [ n ], namely n is more than or equal to 2;
(4.5) calculating the maximum deformation amount omega max of the inner ring part of the high-pressure stuffing box according to the formula (2), wherein for the high-pressure compressor, the omega max is less than or equal to 0.003 for ensuring reliable sealing.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical scope of the present invention, and equivalent alternatives or modifications according to the technical solution and the utility model concept of the present invention should be covered within the scope of the present invention.
Claims (1)
1. The stress and strain calculation method of the high-pressure stuffing box of the large reciprocating compressor is characterized by comprising the following steps of:
(1) Establishing a stress model analysis of the stuffing box:
(1.1) the working pressure of the high-pressure packing part is p;
(1.2) the pretightening force of the bolt of the packing assembly is F0, the lateral acting force is F1, the total thickness of the packing box is H, the depth of a sealing groove is H1, the diameter of the sealing groove is D, and the diameter of a piston rod passing through part of circular holes is D1;
(1.3) by analyzing the stress of each stuffing box, further analyzing, the stress of the stuffing box is that the circular ring is pressed, the pressure of the circular ring seal is q equal to the seal working pressure p of the stuffing, the outer diameter dimension of the circular ring is defined as D =2b, the inner diameter dimension is defined as D1=2a, and the thickness of the circular ring is defined as t = H-H1;
(2) Analysis of the dangerous cross section of the stuffing box stress and strain:
(2.1) in order to ensure the sealing of the polytetrafluoroethylene or polyether-ether-ketone packing, the packing box must be designed into a rigid reinforced connecting plate, when the high-pressure packing assembly works, the deformation of a compressed ring, namely the strain is omega, the bending stress sigma theta generated by the ring plate is extremely small, the internal stress sigma r in the diameter direction is extremely small, a coordinate axis is established by taking the center of the ring as an original point, and the distance from the center of the ring is r;
(2.2) maximum deformation and maximum bending stress occur at the edge of the annular plate r = a, here the dangerous section;
(3) Calculating the maximum stress and the maximum strain of the stuffing box:
is defined as
The maximum bending stress σ max and the maximum deformation ω max are formulated as:
σmax＝(σθ)k＝K ＝αm 2 q (1)
wherein
E is the elastic modulus of the material, and the elastic modulus of stainless steel is 205000Mpa;
correction coefficients of alpha and beta related to stress according to K value;
(4) Calculating the fatigue strength of the stuffing box and meeting the rigidity requirement:
(4.1) when the high-pressure packing works, working pressure is periodically changed according to the crank angle of 0-360 degrees, the stress load of a circular ring plate of a packing box is also periodic, the suction pressure of a compressor is defined as PS, the exhaust pressure is defined as PD, the maximum and minimum bending stresses at the dangerous section of the packing circular ring are respectively sigma max and sigma min according to the formula (1), the average bending stress sigma m and the stress amplitude sigma a are defined, and the calculation formula is as follows:
(4.2) defining the fatigue strength limit as sigma-1, and calculating the formula as follows:
wherein
Defining the equivalent coefficient; sigma B Defined as tensile strength; when stainless steel is ground and processed under the action of tension-compression circulating stress, the equivalent coefficient of the stainless steel is greater or less than>
Taking 0.35; the tensile strength of the stainless steel is 780Mpa; calculating the fatigue strength limit sigma-1 =273mpa according to the formula (5);
(4.3) defining the safety coefficient of the fatigue strength of the inner ring part of the high-pressure filler under the action of bending stress as n, wherein the calculation formula is as follows:
wherein (k) σD ) Defining the amplitude comprehensive average coefficient of the bending stress; integrated average coefficient (k) σD ) The magnitude of the stress is related to the stress concentration, the size of the inner ring of the packing and the surface roughness, according to the stress condition (k) σD ) The value is 3.1;
(4.4) according to the formula (6), the safety coefficient of the fatigue strength is n, and the calculation formula is as follows:
defining the maximum allowable safety factor when the stuffing box works as [ n ], wherein for a high-pressure compressor, [ n ] =2;
the safety coefficient of the fatigue strength of the high-pressure stuffing box calculated according to the formula (7) is n ≧ n, namely n ≧ 2.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102187055A (en) * | 2008-10-13 | 2011-09-14 | 国际壳牌研究有限公司 | Circulated heated transfer fluid systems used to treat a subsurface formation |
| CN202203077U (en) * | 2011-08-17 | 2012-04-25 | 北京金凯威通用机械有限公司 | Leakproof structure of polycrystalline silicon tail gas compressor |
| CN202250694U (en) * | 2011-09-18 | 2012-05-30 | 蚌埠市鸿申天然气工程成套设备有限责任公司 | Corrosion-resistant reciprocating piston compressor |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004017997A (en) * | 2002-06-13 | 2004-01-22 | Toyobo Co Ltd | Paper box having polyester film window |
| US8476352B2 (en) * | 2008-08-08 | 2013-07-02 | Exxonmobil Chemical Patents Inc. | Elastomeric compositions comprising hydrocarbon polymer additives having improved impermeability |
| CN101629010B (en) * | 2009-08-07 | 2011-12-14 | 厦门大学 | Epoxy/POSS/carbon fiber nanometer composite material for light sports equipment and preparation method thereof |
| CN101738276A (en) * | 2009-11-04 | 2010-06-16 | 广东美的集团芜湖制冷设备有限公司 | Preestimating method for determining stress of air conditioner tubing in transport falling process and stress paint |
| KR101268481B1 (en) * | 2011-08-12 | 2013-06-04 | 한국수력원자력 주식회사 | The test equipment of friction coefficient of valve packing and method thereof |
| CN103399993B (en) * | 2013-07-22 | 2016-04-06 | 合肥通用机械研究院 | Reciprocating compressor crankshaft reliability Optimum Design method |
| CN108119347A (en) * | 2017-12-19 | 2018-06-05 | 浙江强盛压缩机制造有限公司 | A kind of double acting control device of air compressor machine off-load cylinder |
| CN108409997B (en) * | 2018-03-29 | 2021-02-19 | 武汉大学苏州研究院 | Preparation method of ultrahigh-strength anisotropic hydrogel containing cellulose nanowhiskers |
| CN109033709B (en) * | 2018-08-30 | 2020-03-31 | 电子科技大学 | Component fatigue life evaluation method based on nonlinear fatigue damage accumulation theory |
| CN109635385B (en) * | 2018-11-28 | 2022-11-04 | 北京工业大学 | Part service life prediction method comprehensively considering fatigue strength influence factors |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102187055A (en) * | 2008-10-13 | 2011-09-14 | 国际壳牌研究有限公司 | Circulated heated transfer fluid systems used to treat a subsurface formation |
| CN202203077U (en) * | 2011-08-17 | 2012-04-25 | 北京金凯威通用机械有限公司 | Leakproof structure of polycrystalline silicon tail gas compressor |
| CN202250694U (en) * | 2011-09-18 | 2012-05-30 | 蚌埠市鸿申天然气工程成套设备有限责任公司 | Corrosion-resistant reciprocating piston compressor |
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