Automatic design method of concentration gradient generator

Abstract

The invention relates to the technical field of micro-fluidic chips, in particular to an automatic design method of a concentration gradient generator. Comprising the following steps: S1, establishing a flow resistance calculation model; s2, setting constraint conditions of a flow resistance calculation model, and obtaining flow resistance on the left side of the mixing point on the kth outlet channel and flow resistance on the right side of the mixing point on the (k-1) th outlet channel; s3, iteratively calculating the number of snakelike units in a first non-mixing area pipeline in the kth outlet channel and the length of the snakelike units; s4, calculating the length of the snakelike unit in the mixing area pipeline in the kth outlet pipeline; s5, iteratively calculating the number and the length of the snakelike units in the second non-mixing area pipeline in the kth outlet pipeline; according to the method, simplified and efficient automatic calculation is carried out, personal errors are avoided, and the design verification efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of microfluidic chips, and in particular to an automatic design method for a concentration gradient generator. Background Art

[0002] With the development of microfluidic technology, microfluidic chips have been widely used in biomedicine, chemical analysis, drug development and other fields. Microfluidic chips achieve precise flow control, mixing and reaction processes by manipulating liquids at the micrometer scale; however, in practical applications, how to design a reasonable pipeline structure to ensure uniform mixing of fluids, control flow resistance and optimize the space utilization of the chip has always been a difficult and key point in the design of microfluidic chips. The concentration gradient generator is a type of microfluidic chip.

[0003] Traditional concentration gradient generators usually use simple straight or zigzag pipeline structures. Although these structures are relatively simple to design and manufacture, they have limitations in mixing efficiency and flow resistance control. For example, in the dilution process of multiple channels, if the pipeline length and resistance are not designed properly, it may cause uneven mixing of the fluid, thus affecting the accuracy of the experimental results. In addition, with the continuous expansion of the functions of microfluidic chips, the demand for multi-channel and multi-function is increasing, which further increases the complexity requirements for chip pipeline design.

[0004] The traditional design of concentration gradient generator requires calculation of the flow resistance length of each part based on the principle. The principle is complex, the calculation is difficult and the accuracy is low. Changing a parameter requires recalculation, which is cumbersome, error-prone and inefficient.

[0005] Therefore, there is an urgent need to provide an automatic design method for a concentration gradient generator, which can achieve simplified and efficient automatic calculations compared to the existing technology, avoid human errors, and improve design verification efficiency. Summary of the invention

[0006] The present invention solves the technical problems existing in the prior art and provides an automatic design method for a concentration gradient generator.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] An automatic design method for a concentration gradient generator comprises the following steps:

[0009] S1. Establish a flow resistance calculation model;

[0010] S2. Set the constraint conditions of the flow resistance calculation model to obtain the flow resistance on the left side of the mixing point on the kth outlet channel and the flow resistance on the right side of the mixing point on the (k-1)th outlet channel;

[0011] S3, taking the flow resistance on the left side of the mixing point on the kth outlet channel obtained in step S2 as the total length of the first non-mixing zone pipeline in the kth outlet pipeline, and iteratively calculating the number and length of the serpentine units in the first non-mixing zone pipeline in the kth outlet channel;

[0012] S4, calculating the length of the serpentine unit in the mixing zone pipeline in the kth outlet pipeline;

[0013] S5. Using the flow resistance on the right side of the mixing point on the (k-1)th outlet channel obtained in step S2 as the total length of the second non-mixing zone pipeline in the kth outlet pipeline, iteratively calculate the number and length of the serpentine units in the second non-mixing zone pipeline in the kth outlet pipeline.

[0014] Furthermore, step S3 specifically includes the following steps:

[0015] S31, setting the first turning point of the k-th outlet pipeline bevel pipeline as the initial coordinate of the first non-mixing zone pipeline;

[0016] S32, based on the initial coordinates set in step S31, setting the first iteration start condition, and when the first iteration start condition is met, performing iteration, and adding a serpentine unit in each iteration;

[0017] S33, setting the first iteration constraint condition of step S32, when the first iteration stop condition is met, stopping the iteration, and obtaining the number of serpentine units and the length of the serpentine units of the first non-mixing zone pipeline in the kth outlet pipeline;

[0018] S34. Verify the length of the serpentine unit obtained in step S33, set the maximum length and minimum length of a serpentine unit in the mixing zone pipeline, and set verification constraints. If the verification constraints are met, proceed to step S4. If the verification constraints are not met, change the initial coordinates in step S31 and repeat steps S31-S34.

[0019] Furthermore, the first iteration start condition in step S32 is specifically:

[0020] ucnn=0;

[0021] The first iteration end condition in step S33 is specifically:

[0022] ucln≥maxlength;

[0023] In the above formula, ucnn represents the number of serpentine units, ucln represents the length of the serpentine unit, and maxlength represents the maximum length of a serpentine unit.

[0024] There is the following relationship between the number of serpentine units and the length of the serpentine unit:

[0025] ucln=(RL(k)-LK(k)) / ucnn;

[0026] In the above formula, RL(k) represents the flow resistance on the left side of the mixing point on the kth outlet channel, and LK(k) represents the length of the hypotenuse pipe in the kth outlet pipe.

[0027] Furthermore, the verification constraint in step S34 is:

[0028] min_mixblanklen <ulnn<max_minblanklen;

[0029] In the above formula, min_mixblanklen represents the minimum length of a serpentine unit in the mixing zone pipe, and max_minblanklen represents the maximum length of a serpentine unit in the mixing zone pipe.

[0030] Further, the specific method of step S4 is: the number of serpentine units in the mixing zone pipeline is iterated from 0, the number of serpentine units in the mixing zone pipeline is increased by 1 in each iteration, the second iteration end condition is set, and when the third iteration termination condition is met, the iteration is terminated;

[0031] The termination condition of the third iteration is as follows:

[0032] sclm <mincls;

[0033] scln=R(k-1) / scnn;

[0034] In the above formula, scln represents the number of serpentine units in the mixing zone pipeline, sclm represents the length of the serpentine unit in the mixing zone pipeline, mincls represents the set minimum length of the serpentine unit in the mixing zone pipeline, and R(k-1) represents the flow resistance of the connecting channel on the right side of the mixing point on the (k-1)th outlet channel.

[0035] Furthermore, S5 specifically includes the following steps:

[0036] S51, setting the length of the serpentine unit in the second non-mixing zone pipeline in the k-th outlet channel, adding one serpentine unit in sequence, iterating, setting the third iteration termination condition, and stopping the iteration when the third iteration termination condition is met, and obtaining the number of serpentine units in the second non-mixing zone pipeline in the k-th outlet channel;

[0037] S52. Set the fourth iteration termination condition. When the fourth iteration termination condition is met, output the length of the serpentine unit at this time as the length of the serpentine unit in the second non-mixing zone pipeline in the kth outlet channel. If the fourth iteration termination condition is not met, repeat steps S51-S52 until the fourth iteration termination condition is met.

[0038] Furthermore, the third iteration termination condition in step S51 is:

[0039] (R(k-1)-dcnn×B)<0;

[0040] In the above formula, dcnn represents the number of serpentine units in the second non-mixing zone pipeline, and B represents the length of the serpentine unit in the second non-mixing zone pipeline.

[0041] Furthermore, the fourth iteration termination condition in step S52 is:

[0042] dcln≥maxlength;

[0043] dcln=R(k-1) / dcnn;

[0044] In the above formula, dcln represents the length of the serpentine unit in the second non-mixing zone pipeline.

[0045] Furthermore, the expression of the flow resistance calculation model in step S1 is:

[0046] QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0047] QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0048] RL(k)=(RL(k+1)×QL(k+1)+Rm×(QR(k+1)+QL(k+1))+Rs×QR(k)) / QL(k);

[0049] R(k)=(Rs×QR(k+1)+Rm×(QR(k-1)+QL(k-1))+R(k-1)×Q(k-1)) / Q(k);

[0050] In the above formula, QL(k) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the kth outlet channel, C(k+1) represents the concentration of the solution in the (k+1)th outlet channel, C(k) represents the concentration of the solution in the kth outlet channel, QR(k-1) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the (k-1)th outlet channel, Q(k) represents the flow rate of the kth outlet solution, C0 represents the concentration of the diluent, RL(k) represents the flow resistance in the connecting channel on the left side of the mixing point on the kth outlet channel, RL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, and QL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel. QR(k+1) represents the flow rate of the solution in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel, QL(k+1) represents the flow rate of the solution in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, QR(k) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the kth outlet channel, QL(k-1) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the (k-1)th outlet channel, R(k) represents the flow resistance of the connecting channel on the right side of the mixing point on the kth outlet channel, and R(k+1) represents the flow resistance in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel; Rm and Rs both represent the set initial values, both are constants.

[0051] Furthermore, the constraints of the flow resistance calculation model in step S2 are set as follows:

[0052] QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0053] QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0).

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) The present invention performs simplified and efficient automatic calculation by reasonably calculating the pipeline length and determining the number of cycles, thereby avoiding human errors and improving the efficiency of design verification.

[0056] (2) Compared with the traditional design method, the present invention rationally utilizes the internal space of the microfluidic chip, improves the overall performance and application breadth of the microfluidic chip, can better adapt to the complex fluid mechanics environment, and significantly improves the performance and design efficiency of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of the present invention.

[0058] Figure 2 It is a schematic diagram of the structure of the concentration gradient generator designed by the present invention.

[0059] Figure 3 This is a schematic diagram of the connection between a 9-channel concentration gradient generator and other multi-channel or multi-unit microfluidic chips.

[0060] Description of reference numerals:

[0061] 1. Mixing zone; 2. First non-mixing zone; 3. Second non-mixing zone; 4. Beveled edge pipe. DETAILED DESCRIPTION

[0062] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. It should be noted that the orientation or position relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", etc. is based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0063] like Figure 1 , Figure 2 As shown, the present invention provides an automatic design method for a concentration gradient generator, comprising the following steps:

[0064] S1. Based on the laminar diffusion principle, Kirchhoff's current theorem, equivalent circuit principle, and Poiseuille's theorem, a flow resistance calculation model is established. The specific construction method is as follows:

[0065] Laminar diffusion principle:

[0066]

[0067] In the above formula, ρ represents the material density, C represents the material concentration, and V represents the flow velocity vector. represents the differential operator, D represents the diffusion coefficient, and t represents the flow time.

[0068] Poiseuille's theorem formula:

[0069]

[0070] In the above formula, Q represents the liquid flow rate, r represents the channel radius, Δp represents the pressure drop, η represents the viscosity coefficient, L represents the pipe length, R represents the flow resistance, ω represents the pipe width, and h represents the pipe height.

[0071] The principle of equivalent circuit is: the equivalent circuit analogy method is to equate the fluid flow to current, the fluid resistance in the microchannel to resistance, the pressure drop at both ends of the channel to voltage, the chip inlet to power supply, and the chip outlet to ground.

[0072] Kirchhoff's Current Theorem: In a microfluidic network loop, for a node with N inflow and outflow paths, the sum of the flow into the node should be the same as the sum of the flow leaving the node, that is:

[0073]

[0074] In the above formula, Q n Indicates the traffic of the nth path of the node, where n is 1-N.

[0075] Similarly, in a loop with M branches in a microfluidic network, the vector sum of the pressure drops is 0, that is:

[0076]

[0077] In the above formula, Δp i The vector representing the voltage drop of the i-th branch, where i is 1-M.

[0078] Therefore, the flow resistance calculation model is expressed by the following formula:

[0079] QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0080] QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0081] RL(k)=(RL(k+1)×QL(k+1)+Rm×(QR(k+1)+QL(k+1))+Rs×QR(k)) / QL(k);

[0082] R(k)=(Rs×QR(k+1)+Rm×(QR(k-1)+QL(k-1))+R(k-1)×Q(k-1)) / Q(k);

[0083] In the above formula, QL(k) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the kth outlet channel, C(k+1) represents the concentration of the solution in the (k+1)th outlet channel, C(k) represents the concentration of the solution in the kth outlet channel, QR(k-1) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the (k-1)th outlet channel, Q(k) represents the flow rate of the kth outlet solution, C0 represents the concentration of the diluent, RL(k) represents the flow resistance in the connecting channel on the left side of the mixing point on the kth outlet channel, RL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, and QL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel. QR(k+1) represents the flow rate of the solution in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel, QL(k+1) represents the flow rate of the solution in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, QR(k) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the kth outlet channel, QL(k-1) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the (k-1)th outlet channel, R(k) represents the flow resistance in the connecting channel on the right side of the mixing point on the kth outlet channel, and R(k+1) represents the flow resistance in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel; Rm and Rs both represent the set initial values, both are constants.

[0084] S2. Set the constraints of the flow resistance calculation model, set the concentration of the diluent and the radius of the serpentine unit bend as known conditions, and obtain the flow rate on the left side of the mixing point on the kth outlet channel and the flow rate on the right side of the mixing point on the kth outlet channel. The constraints of the flow calculation model are:

[0085] QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0086] QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0);

[0087] Through the above constraints, QR(k) and QL(k) are obtained respectively. QR(k) and QL(k) are brought into the flow resistance calculation model to obtain R(k) and RL(k).

[0088] S3, setting the value of RL(k) obtained in step S2 to the total length of the first non-mixing zone pipeline in the k-th outlet channel, the first non-mixing zone pipeline is the non-mixing zone pipeline above the mixing zone pipeline, based on which, calculating the number of serpentine units in the first non-mixing zone pipeline in the k-th outlet channel and the length of the serpentine units; specifically comprising the following steps:

[0089] S31, setting the first turning point of the k-th outlet pipeline bevel pipeline as the initial coordinate of the first non-mixing zone pipeline.

[0090] S32. Based on the initial coordinates set in step S31, set the first iteration start condition, satisfy the first iteration start condition, perform iteration, add a serpentine unit in each iteration, the size of each serpentine unit is the same, and iterate to add serpentine units in the vertical direction.

[0091] S33. Set the first iteration stop condition of step S32, and stop the iteration when the first iteration stop condition is met.

[0092] The first iteration start conditions are as follows:

[0093] ucnn=0;

[0094] The first iteration stop condition is as follows:

[0095] ucln≥maxlength;

[0096] In the above formula, ucnn represents the number of serpentine units, ucln represents the length of the serpentine unit, and maxlength represents the maximum length of a serpentine unit.

[0097] After entering the iteration, the number of units is set to increase by 1 in each iteration, the length of the serpentine unit is calculated, and it is determined whether the first iteration constraint is met.

[0098] There is the following relationship between the number of serpentine units and the length of the serpentine unit:

[0099] ucln=(RL(k)-LK(k)) / ucnn;

[0100] In the above formula, LK(k) represents the length of the hypotenuse pipe in the kth outlet pipe.

[0101] S34, verify the length of the serpentine unit obtained in step S33, set the maximum length and minimum length of a serpentine unit in the mixing zone pipeline, and set verification constraints. If the verification constraints are met, then proceed to step S4. If the verification constraints are not met, then change the initial coordinates in step S31 and re-perform steps S31-S34. The verification constraints are:

[0102] min_mixblanklen <ulnn<max_minblanklen;

[0103] In the above formula, min_mixblanklen represents the minimum length of a serpentine unit in the mixing zone pipe, and max_minblanklen represents the maximum length of a serpentine unit in the mixing zone pipe.

[0104] S4, calculate the length of the serpentine unit in the mixing zone pipe in the kth outlet pipe; the number of serpentine units in the mixing zone pipe is iterated from 0, and the number of serpentine units in the mixing zone pipe is increased by 1 in each iteration, and the second iteration end condition is set. When the third iteration termination condition is met, the iteration is terminated.

[0105] The termination condition of the third iteration is as follows:

[0106] sclm <mincls;

[0107] scln=R(k-1) / scnn;

[0108] In the above formula, scln represents the number of serpentine units in the mixing zone pipeline, sclm represents the length of the serpentine unit in the mixing zone pipeline, and mincls represents the set minimum length of the serpentine unit in the mixing zone pipeline.

[0109] The iteration is terminated, and the length of the serpentine unit in the mixing zone pipe in the kth outlet pipe is obtained.

[0110] S5, setting the value of R(k-1) obtained in step S2 to the total length of the second non-mixing zone pipeline in the k-th outlet channel, the second non-mixing zone pipeline is the non-mixing zone pipeline below the mixing zone pipeline, based on which, the number of serpentine units in the second non-mixing zone pipeline in the k-th outlet channel and the length of the serpentine units are calculated; specifically comprising the following steps:

[0111] S51. Set the length of the serpentine unit in the second non-mixing zone pipe in the k-th outlet channel, add one serpentine unit in turn, iterate, set the third iteration termination condition, and stop the iteration when the third iteration termination condition is met to obtain the number of serpentine units in the second non-mixing zone pipe in the k-th outlet channel.

[0112] The third iteration termination condition is:

[0113] (R(k-1)-dcnn×B)<0;

[0114] In the above formula, dcnn represents the number of serpentine units in the second non-mixing zone pipeline, and B represents the length of the serpentine unit in the second non-mixing zone pipeline.

[0115] S52, setting the fourth iteration termination condition. When the fourth iteration termination condition is met, output the length of the serpentine unit at this time as the length of the serpentine unit in the second non-mixing zone pipeline in the kth outlet channel. If the fourth iteration termination condition is not met, repeat the steps S51-S52 until the fourth iteration termination condition is met. The fourth iteration termination condition is:

[0116] dcln≥maxlength;

[0117] dcln=R(k-1) / dcnn;

[0118] In the above formula, dcln represents the length of the serpentine unit in the second non-mixing zone pipeline.

[0119] Figure 3 The 9-channel concentration gradient generator is a schematic diagram of connecting and using other multi-channel or multi-unit microfluidic chips, wherein the serpentine channel of the 9-channel concentration gradient generator is designed using the method provided in the present invention, and has good performance and application breadth. For other multi-channel or multi-unit microfluidic chips, microfluidic-based The cytotoxicity test chip is connected to the concentration gradient generator designed using the method of the present invention. In fact, those skilled in the art can also select other suitable chip types according to actual needs and use them in combination with the concentration gradient generator designed using the method of the present invention. Those skilled in the art are capable of applying the concentration gradient generator designed using the method of the present invention to other scenarios.

[0120] The present invention performs simplified and efficient automatic calculations through reasonable pipe length calculations and determination of the number of cycles, thereby avoiding human errors, improving design verification efficiency, and ensuring uniform mixing of liquids in different areas by effectively controlling fluid resistance.

[0121] The method of the present invention fully considers the utilization rate of the internal space of the chip, so that more functional areas can be accommodated within the limited chip area, thereby improving the overall performance and application breadth of the chip. The invention not only solves the deficiencies of traditional microfluidic chips in terms of flow resistance control and mixing efficiency, but also provides a new method for the design of highly complex and multifunctional microfluidic chips.

[0122] The present invention is suitable for optimizing serpentine channels in microfluidic chip design, especially in the design of isotropic concentration generators with multiple output ports. Through precise calculation and optimization, the performance of the chip can be effectively improved and the errors in the experiment can be reduced. The present invention is suitable for the research and development of microfluidic devices in the fields of biomedicine, chemical analysis, etc., and can significantly improve the accuracy and efficiency of the experiment.

[0123] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. An automatic design method for a concentration gradient generator, characterized in that: The following steps are involved: S1. Establish a flow resistance calculation model; S2. Set the constraint conditions of the flow resistance calculation model to obtain the flow resistance on the left side of the mixing point on the kth outlet channel and the flow resistance on the right side of the mixing point on the (k-1)th outlet channel; S3, taking the flow resistance on the left side of the mixing point on the kth outlet channel obtained in step S2 as the total length of the first non-mixing zone pipeline in the kth outlet pipeline, and iteratively calculating the number and length of the serpentine units in the first non-mixing zone pipeline in the kth outlet channel; S4, calculating the length of the serpentine unit in the mixing zone pipeline in the kth outlet pipeline; S5. Using the flow resistance on the right side of the mixing point on the (k-1)th outlet channel obtained in step S2 as the total length of the second non-mixing zone pipeline in the kth outlet pipeline, iteratively calculate the number and length of the serpentine units in the second non-mixing zone pipeline in the kth outlet pipeline.

2. The automatic design method of a concentration gradient generator according to claim 1, characterized in that: The S3 step specifically includes the following steps: S31, setting the first turning point of the k-th outlet pipeline bevel pipeline as the initial coordinate of the first non-mixing zone pipeline; S32, based on the initial coordinates set in step S31, setting the first iteration start condition, and when the first iteration start condition is met, performing iteration, and adding a serpentine unit in each iteration; S33, setting the first iteration constraint condition of step S32, when the first iteration stop condition is met, stopping the iteration, and obtaining the number of serpentine units and the length of the serpentine units of the first non-mixing zone pipeline in the kth outlet pipeline; S34. Verify the length of the serpentine unit obtained in step S33, set the maximum length and minimum length of a serpentine unit in the mixing zone pipeline, and set verification constraints. If the verification constraints are met, proceed to step S4. If the verification constraints are not met, change the initial coordinates in step S31 and repeat steps S31-S34.

3. The automatic design method of a concentration gradient generator according to claim 2, characterized in that: The first iteration start condition in step S32 is specifically: ucnn=0; The first iteration end condition in step S33 is specifically: ucln≥maxlength; In the above formula, ucnn represents the number of serpentine units, ucln represents the length of the serpentine unit, and maxlength represents the maximum length of a serpentine unit. There is the following relationship between the number of serpentine units and the length of the serpentine unit: ucln=(RL(k)-LK(k)) / ucnn; In the above formula, RL(k) represents the flow resistance on the left side of the mixing point on the kth outlet channel, and LK(k) represents the length of the bevel pipe in the kth outlet pipe.

4. The automatic design method of a concentration gradient generator according to claim 3, characterized in that: The verification constraints in step S34 are: min_mixblanklen <ulnn<max_minblanklen; In the above formula, min_mixblanklen represents the minimum length of a serpentine unit in the mixing zone pipe, and max_minblanklen represents the maximum length of a serpentine unit in the mixing zone pipe.

5. The automatic design method of a concentration gradient generator according to claim 1, characterized in that: The specific method of step S4 is: the number of serpentine units in the mixing zone pipeline is iterated from 0, the number of serpentine units in the mixing zone pipeline is increased by 1 in each iteration, the second iteration end condition is set, and the iteration is ended when the third iteration termination condition is met; The termination condition of the third iteration is as follows: sclm <mincls; scln=R(k-1) / scnn; In the above formula, scln represents the number of serpentine units in the mixing zone pipeline, sclm represents the length of the serpentine unit in the mixing zone pipeline, mincls represents the set minimum length of the serpentine unit in the mixing zone pipeline, and R(k-1) represents the flow resistance of the connecting channel on the right side of the mixing point on the (k-1)th outlet channel.

6. The automatic design method of a concentration gradient generator according to claim 5, characterized in that: S5 specifically includes the following steps: S51, setting the length of the serpentine unit in the second non-mixing zone pipeline in the k-th outlet channel, adding one serpentine unit in sequence, iterating, setting the third iteration termination condition, and stopping the iteration when the third iteration termination condition is met, and obtaining the number of serpentine units in the second non-mixing zone pipeline in the k-th outlet channel; S52. Set the fourth iteration termination condition. When the fourth iteration termination condition is met, output the length of the serpentine unit at this time as the length of the serpentine unit in the second non-mixing zone pipeline in the kth outlet channel. If the fourth iteration termination condition is not met, repeat steps S51-S52 until the fourth iteration termination condition is met.

7. The automatic design method of a concentration gradient generator according to claim 6, characterized in that: The third iteration termination condition in step S51 is: (R(k-1)-dcnn×B)<0; In the above formula, dcnn represents the number of serpentine units in the second non-mixing zone pipeline, and B represents the length of the serpentine unit in the second non-mixing zone pipeline.

8. The automatic design method of a concentration gradient generator according to claim 6, characterized in that: The fourth iteration termination condition in step S52 is: dcln≥maxlength; dcln=R(k-1) / dcnn; In the above formula, dcln represents the length of the serpentine unit in the second non-mixing zone pipeline.

9. The automatic design method of a concentration gradient generator according to claim 1, characterized in that: The expression of the flow resistance calculation model in step S1 is: QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0); QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0); RL(k)=(RL(k+1)×QL(k+1)+Rm×(QR(k+1)+QL(k+1))+Rs×QR(k)) / QL(k); R(k)=(Rs×QR(k+1)+Rm×(QR(k-1)+QL(k-1))+R(k-1)×Q(k-1)) / Q(k); In the above formula, QL(k) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the kth outlet channel, C(k+1) represents the concentration of the solution in the (k+1)th outlet channel, C(k) represents the concentration of the solution in the kth outlet channel, QR(k-1) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the (k-1)th outlet channel, Q(k) represents the flow rate of the kth outlet solution, C0 represents the concentration of the diluent, RL(k) represents the flow resistance in the connecting channel on the left side of the mixing point on the kth outlet channel, RL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, and QL(k+1) represents the flow resistance in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel. The flow rate of the diluent in the connecting channel on the left side of the mixing point on the outlet channel, QR(k+1) represents the flow rate of the solution in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel, QL(k+1) represents the flow rate of the solution in the connecting channel on the left side of the mixing point on the (k+1)th outlet channel, QR(k) represents the flow rate of the diluent in the connecting channel on the right side of the mixing point on the kth outlet channel, QL(k-1) represents the flow rate of the diluent in the connecting channel on the left side of the mixing point on the (k-1)th outlet channel, R(k) represents the flow resistance of the connecting channel on the right side of the mixing point on the kth outlet channel, and R(k+1) represents the flow resistance in the connecting channel on the right side of the mixing point on the (k+1)th outlet channel; Rm and Rs both represent the set initial values ​​and are constants.

10. The automatic design method of a concentration gradient generator according to claim 9, characterized in that: The constraints of the flow resistance calculation model in step S2 are: QR(k)=(C(k)-C0)×(QR(k-1)+Q(k)) / (C(k+1)-C0); QL(k)=(C(k+1)-C(k))×(QR(k-1)+Q(k)) / (C(k+1)-C0).

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