A flow field visualization experimental device and method based on a noctiluca biological solution
By constructing a closed-loop circulation system of Noctiluca scintillans biosol, and utilizing the self-luminescence property of Noctiluca scintillans under fluid shear stimulation, the problems of insufficient cost, safety and adaptability to complex boundaries in existing flow field measurement technologies are solved. This achieves low-cost, high-safety flow field visualization and quantitative analysis, which is applicable to a variety of experimental scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN ENG UNIV
- Filing Date
- 2026-04-10
- Publication Date
- 2026-07-07
AI Technical Summary
Existing flow field measurement techniques have shortcomings in terms of cost, safety, adaptability to complex boundaries, and engineering applications with biological tracer media. They are particularly difficult to promote in small and medium-sized laboratories and teaching environments. Furthermore, existing methods suffer from high costs, complex optical path construction, risks of biological radiation, and insufficient adaptability to tracer particles.
Using Noctiluca scintillans as a biological tracer, a flow field visualization experimental device based on Noctiluca scintillans biological solution was constructed. Through a closed-loop circulation system consisting of a culture module, an experimental module, an activity recovery module, and a storage tank, the self-luminescence characteristics of Noctiluca scintillans under fluid shear stimulation were utilized to achieve visualization and quantitative analysis of the flow field, thereby reducing hardware costs and improving safety.
It enables low-cost and high-safety flow field visualization and quantitative analysis, and is applicable to flow fields with complex geometric boundaries and near-wall regions. It has good prospects for engineering application and is suitable for hydrodynamic experiments, marine engineering model tests and teaching demonstrations.
Smart Images
Figure CN122345467A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the interdisciplinary field of fluid dynamics experimental measurement and bio-optics, and in particular to an experimental apparatus and method for visualizing flow fields based on Noctiluca scintillans biosol. Background Technology
[0002] Existing high-precision flow field measurement technologies have significant limitations in terms of cost and engineering complexity.
[0003] 1. Mainstream methods such as particle image velocimetry (PIV) and laser Doppler velocimetry (LDV) rely on high-power laser sources, high-speed cameras, and precise synchronous control systems. The overall system cost is high, and the optical path construction and maintenance are complex, which seriously limits their promotion and application in small and medium-sized laboratories, teaching environments, and multi-point distributed measurement scenarios.
[0004] 2. External laser measurement methods have inherent shortcomings in terms of safety and environmental adaptability. High-level laser equipment poses significant biological radiation risks and imposes strict requirements on operators and experimental sites. Furthermore, in experimental environments containing complex geometric boundaries, highly reflective interfaces, or flammable and explosive media, the stability and safety of laser measurement systems are difficult to guarantee.
[0005] 3. Traditional passive tracer particles are not adaptable to complex shear flow fields. Solid or hollow particles require external light sources for imaging and are susceptible to diffuse and specular reflection interference in the near-wall region, resulting in the loss of key boundary layer information. In addition, the density difference and inertial effect between the tracer particles and the fluid can introduce significant tracking errors in high-acceleration or forced oscillating flows.
[0006] 4. Existing research on bioluminescent fluids mostly focuses on phenomenon demonstration or one-time experiments, lacking a systematic engineering design for the "cultivation-use-recovery-reuse" of biological tracer media. This results in low utilization of biological materials, poor experimental repeatability, and difficulty in forming sustainable and engineering-scalable measurement schemes.
[0007] In summary, existing flow field measurement techniques have shortcomings in terms of economy, safety, adaptability to complex boundaries, and engineering applications of biological tracer media. There is an urgent need for a novel integrated flow field visualization method that can deeply couple the bioluminescent tracer mechanism with engineering experimental systems and enable the recyclability of biological solutions. Summary of the Invention To address the aforementioned problems, this invention provides a flow field visualization experimental device and method based on *Noctiluca scintillans* biosol. The core idea of this invention is to utilize the self-luminescence produced by *Noctiluca scintillans* when stimulated by fluid shear, using it as an active biological tracer medium. By constructing a closed-loop circulation system coupling four components—a biosol culture module, a flow field experimental module, a bioactivity recovery module, and a biosol storage tank—stable use of the *Noctiluca scintillans* solution in multiple rounds of experiments is achieved. This significantly reduces hardware costs while providing intuitive visualization and quantitative analysis capabilities for complex flow field structures.
[0008] To achieve the above objectives, the present invention adopts the following technical solution: a flow field visualization experimental device based on Noctiluca scintillans biosol, comprising a biosol culture module, a flow field experimental module, a bioactivity recovery module, a biosol storage tank, and a bioactivity calibration unit; The biological solution culture module includes an LED light source and a Noctiluca scintillans culture dish. The LED light source is positioned above the Noctiluca scintillans culture dish, which is filled with a Noctiluca scintillans solution. The flow field experimental module includes an experimental dark chamber, and an experimental flow channel, an imaging device, and a flow field excitation model arranged in the experimental dark chamber. The experimental flow channel is connected to the Noctiluca scintillans culture dish, and a delivery pump is installed on the pipe between the two. The imaging device faces the experimental flow channel, and the flow field excitation model is located above the experimental flow channel to apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel, so that the Noctiluca scintillans solution emits light. The bioactivity recovery module includes a light-shielding tank, which is connected to the experimental flow tank through pipe one and pipe two. Pipe one is equipped with a second delivery pump, and pipe two is equipped with a third delivery pump. The biological solution storage tank is connected to the light-shielding tank, and a transfer pump four is installed on the pipeline between the two. The biological solution storage tank is also connected to the Noctiluca scintillans culture dish, and a transfer pump five is installed on the pipeline between the two. The Noctiluca scintillans culture dish, experimental flow cell, and light-shielding container are all equipped with bioactivity calibration units for detecting the luminescence peak of the Noctiluca scintillans solution.
[0009] Furthermore, the bioactivity calibration unit includes a sampling pump, a detection channel, a mechanical stimulation component, a PMT photomultiplier module, and a light-shielding shell. The sampling pump is connected to the detection channel, the mechanical stimulation component is built into the detection channel, and a light-shielding shell is installed on the outside. The mechanical stimulation component has a geometrically induced structure, and the PMT photomultiplier module is arranged radially on the mechanical stimulation component and connected to the light-shielding shell.
[0010] Furthermore, the mechanical stimulation component is a contraction-expansion nozzle or a throttling orifice plate with a fixed pressure drop.
[0011] Furthermore, the flow field excitation model includes a reciprocating drive mechanism and a cylindrical component. The bottom end of the cylindrical component is provided with a heave plate, and the reciprocating drive mechanism drives the cylindrical component to reciprocate in a direction perpendicular to the bottom surface of the experimental flow channel.
[0012] Furthermore, all of the following pumps are peristaltic pumps: pump 1, pump 2, pump 3, pump 4, and pump 5.
[0013] Furthermore, the connecting pipes used in the experimental setup all employ elbow structures with a radius of curvature greater than or equal to 5 times the pipe diameter at the bends.
[0014] Furthermore, the LED light source is an array-type full-spectrum adjustable LED light array, the Noctiluca luminifera culture dish is provided with a nutrient salt replenishment port one, and the light-shielding container is provided with a nutrient salt replenishment port two.
[0015] Furthermore, the imaging device is an EMCCD or sCMOS camera.
[0016] The flow field visualization experimental device based on Noctiluca scintillans biological solution also includes a PLC controller, which is connected to transfer pump one, transfer pump two, transfer pump three, transfer pump four, transfer pump five and biological activity calibration unit respectively.
[0017] An experimental method for flow field visualization, using the aforementioned flow field visualization experimental device based on Noctiluca scintillans biosolution, specifically includes the following steps: S1. Directed cultivation of tracer media: Control the light-dark rhythm of LED light source, adjust the temperature of Noctiluca scintillans solution, and adjust the salinity and pH value of Noctiluca scintillans solution by filling Noctiluca scintillans culture dish with artificial sea salt concentrate or pH buffer solution to induce Noctiluca scintillans to enter a high-activity growth period. S2. Pre-evaluation of tracer medium status and in-situ excitation: The luminescence peak of the Noctiluca scintillans solution in the culture dish is detected by the bioactivity calibration unit. When the preset threshold T1 is reached, the first transfer pump is started to pump the Noctiluca scintillans solution into the experimental flow tank in a quantitative manner. Then the first transfer pump is turned off and the solution is allowed to stand for a predetermined time H1. S3. Perform optical conversion of flow field characteristics: Set the motion state of the flow field excitation model, start the flow field excitation model, apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel, and then turn off the flow field excitation model. During this period, capture the luminescence sequence images through the imaging device. S4. Consider whether to repeat the experiment: Decide whether to conduct the flow field visualization experiment for the next working condition. If so, continue to the next step; if not, start transfer pump two, and pump the Noctiluca scintillans solution into the light-shielding tank through pipe one. Then, turn off transfer pump two, add nutrients to the Noctiluca scintillans solution in the light-shielding tank, and let it stand for the predetermined time H2. After standing, start transfer pump four, pump the Noctiluca scintillans solution in the light-shielding tank into the biological solution storage tank, and then turn off transfer pump four. Then, start transfer pump five, pump the Noctiluca scintillans solution in the biological solution storage tank into the Noctiluca scintillans culture dish, and then turn off transfer pump five to end the experiment. S5. Preliminary activity detection and intelligent sorting: The luminescence peak of the Noctiluca scintillans solution in the experimental flow tank is detected by the bioactivity calibration unit. If the luminescence peak decay rate is less than the preset threshold T2, then step S3 is executed; if the luminescence peak decay rate is greater than or equal to the preset threshold T2, then the next step is continued. S6. Secondary detection and intelligent sorting after activity recovery: Start transfer pump two, and pump the Noctiluca scintillans solution into the light-shielding tank through pipe one. Then, turn off transfer pump two, add nutrients to the Noctiluca scintillans solution in the light-shielding tank, and let it stand for a predetermined time H3. After standing, detect the luminescence peak of the Noctiluca scintillans solution in the light-shielding tank through the bioactivity calibration unit. If the luminescence peak attenuation rate is less than the preset threshold T2, start transfer pump three, and pump the Noctiluca scintillans solution in the light-shielding tank into the experimental flow tank through pipe two. Then, turn off transfer pump three and proceed to step S3. If the luminescence peak attenuation rate is greater than or equal to the preset threshold T2, start transfer pump four, and pump the experimental solution in the light-shielding tank into the biological solution storage tank. Then, turn off transfer pump four, and then start transfer pump one to pump the Noctiluca scintillans solution in the Noctiluca scintillans culture dish into the experimental flow tank. Then, turn off transfer pump one and let it stand for a predetermined time H1. After standing, proceed to step S3.
[0018] Compared with existing technologies, the beneficial effects of the flow field visualization experimental device and method based on Noctiluca scintillans biosolution described in this invention are: 1. This invention utilizes Noctiluca scintillans, which possesses mechanosensitive bioluminescent properties, as an active tracer medium. A recyclable biological tracer medium system is constructed through the coupling of four components: a biological solution culture module, a flow field experiment module, a biological activity recovery module, and a biological solution storage tank. A low-cost, high-safety experimental device and method for flow field visualization and quantitative analysis are designed, significantly reducing experimental consumable costs. This invention exhibits natural adaptability to flow fields with complex geometric boundaries and near-wall regions. It requires no external laser light source, ensuring high experimental safety and a simple system structure. This invention combines qualitative visualization with quantitative physical quantity inversion capabilities, possessing promising engineering application prospects. It is suitable for hydrodynamic experiments, marine engineering model tests, teaching demonstration experiments, and visualization research of complex boundary flow fields.
[0019] 2. This invention utilizes a sampling pump, a detection channel, a mechanical stimulation component, a PMT photomultiplication module, and a light-shielding shell to form a bioactivity calibration unit for detecting the luminescence peak of the Noctiluca scintillans solution. By establishing a calibration relationship model between the luminescence intensity of the Noctiluca scintillans solution and the concentration or activity of Noctiluca scintillans, the activity of the Noctiluca scintillans solution can be accurately detected, ensuring that the activity of the Noctiluca scintillans solution in the experimental flow tank meets the preset experimental threshold, thus facilitating the smooth progress of the experiment.
[0020] 3. All the pumps described in this invention are peristaltic pumps. During the delivery process, the fluid only comes into contact with the inner wall of the hose, which is very suitable for delivering Noctiluca scintillans solution that is sensitive to shear force. In addition, the bends in the connecting pipes used in the experimental device all adopt elbow structures with a radius of curvature greater than or equal to 5 times the pipe diameter. This structure serves as a physical guarantee to ensure that the Noctiluca scintillans biological solution does not undergo unpredictable luminescence during the flow of each module of "cultivation-experiment-recovery-storage", effectively extending the effective working time of a single batch of Noctiluca scintillans solution. Attached Figure Description
[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the flow field visualization experimental device based on Noctiluca scintillans bio-solution according to the present invention; Figure 2 This is a schematic diagram of the structure of the bioactivity calibration unit described in this invention; Figure 3 This is a schematic diagram of the mechanical stimulation component described in this invention; Figure 4 This is a schematic diagram of the flow field excitation model described in this invention; Figure 5 This is a schematic diagram of the structure when the flow field excitation model described in this invention applies mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel. Figure 1 ; Figure 6 This is a schematic diagram of the structure when the flow field excitation model described in this invention applies mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel. Figure 2 ; Figure 7 This is a flowchart of an experimental method for visualizing a flow field as described in this invention; In the diagram: 1-LED light source; 2-Noctiluca scintillans culture dish; 3-Dark chamber; 4-Experimental flow channel; 5-Imaging equipment; 6-Flow field excitation model; 7-Light shielding tank; 8-Biological solution storage tank; 9-Biological activity calibration unit; 10-PLC controller; 61-Reciprocating drive mechanism; 62-Cylindrical component; 621-Heave plate; 91-Sampling pump; 92-Mechanical stimulation component; 93-PMT photomultiplier module; 94-Light-shielding housing; 95-Solution inlet; 96-Solution outlet; 97-Connector 1; 98-Connector 2; 101 - Pump 1; 102 - Pump 2; 103 - Pump 3; 104 - Pump 4; 105 - Pump 5; A is the high-brightness area, B is the medium-brightness area, and C is the low-brightness area. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.
[0023] I. Detailed Implementation Method 1, see [link / reference] Figure 1-7 This embodiment describes a flow field visualization experimental device based on Noctiluca scintillans biosol, which includes a biosol culture module, a flow field experimental module, a bioactivity recovery module, a biosol storage tank 8, and a bioactivity calibration unit 9. The biological solution culture module includes an LED light source 1 and a Noctiluca scintillans culture dish 2. The LED light source 1 is positioned above the Noctiluca scintillans culture dish 2, which is filled with a Noctiluca scintillans solution. The flow field experimental module includes an experimental dark chamber 3, and an experimental flow channel 4, an imaging device 5, and a flow field excitation model 6 arranged in the experimental dark chamber 3. The experimental flow channel 4 is connected to the Noctiluca scintillans culture dish 2, and a delivery pump 101 is provided on the pipe between the two. The imaging device 5 faces the experimental flow channel 4, and the flow field excitation model 6 is located above the experimental flow channel 4. It is used to apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel 4, so that the Noctiluca scintillans will produce transient autoluminescence under mechanical stimulation. The bioactivity recovery module includes a light-shielding tank 7, which is connected to the experimental flow tank 4 through pipe one and pipe two. Pipe one and pipe two are connected in parallel. Pipe one is equipped with a second delivery pump 102, and pipe two is equipped with a third delivery pump 103. The biological solution storage tank 8 is connected to the light-shielding tank 7, and a transfer pump 104 is installed on the pipeline between the two. The biological solution storage tank 8 is also connected to the Noctiluca scintillans culture dish 2, and a transfer pump 105 is installed on the pipeline between the two. The biological solution storage tank 8 is used to temporarily store the Noctiluca scintillans solution that has suffered severe physiological damage after use, so as to avoid the negative impact of the Noctiluca scintillans solution with experimental residual stress and metabolic waste on the stable population in the Noctiluca scintillans culture dish 2.
[0024] The Noctiluca scintillans culture dish 2, experimental flow tank 4, and light-shielding tank 7 are all equipped with bioactivity calibration units 9, which are used to detect the luminescence peak of the Noctiluca scintillans solution. Based on the pre-established calibration relationship model between the luminescence intensity of the Noctiluca scintillans solution and the concentration or activity of Noctiluca scintillans, the activity of the Noctiluca scintillans solution is determined.
[0025] Preferably, the Noctiluca scintillans culture dish 2 is equipped with a temperature sensor, a conductivity sensor, and a pH sensor.
[0026] See attached document Figure 2 and 3 Preferably, the bioactivity calibration unit 9 is a functional integrated module for characterizing the physiological activity state and response ability of Noctiluca scintillans. Its core structure includes a sampling pump 91, a detection channel, a mechanical stimulation component 92, a PMT (Photomultiplier Tube) photomultiplication module 93, and a light-shielding shell 94. The sampling pump 91 is a micro sampling pump, which is connected to the detection channel. The mechanical stimulation component 92 is built into the detection channel, and a light-shielding shell 94 is installed on the outside. The mechanical stimulation component 92 is a standardized geometrically induced structure. The PMT photomultiplication module 93 is arranged radially to the mechanical stimulation component 92 and is connected to the light-shielding shell 94. The solution inlet 95 and the solution outlet 96 are both connected to the Noctiluca scintillans culture dish 2, the experimental flow tank 4, or the light-shielding container 7 to form a circulation loop. After the solution detection is completed, it returns to the original container. The light-shielding shell 94 is provided with a first connector 97 and a second connector 98 at both ends. During operation, sampling pump 91 pumps a small amount of *Noctiluca scintillans* solution (taken from *Noctiluca scintillans* culture dish 2, experimental flow tank 4, or light-shielding container 7) into the detection channel through a connecting pipe. As the solution flows through mechanical stimulation component 92 with a standardized geometric induction structure, it is subjected to controlled shear force, thereby inducing *Noctiluca scintillans* to produce a transient bioluminescent response. PMT photomultiplier module 93 is responsible for capturing the luminescence intensity signal generated by this stimulation, and its built-in data processing module extracts parameters such as luminescence peak value and attenuation rate. Based on a pre-established calibration relationship between luminescence intensity and *Noctiluca scintillans* concentration or activity, it outputs an evaluation index of the *Noctiluca scintillans* solution activity.
[0027] Preferably, the mechanical stimulation component 92 is a contraction-expansion nozzle or a throttling orifice plate with a fixed pressure drop.
[0028] Preferably, the flow field excitation model 6 includes a reciprocating drive mechanism 61 and a cylindrical member 62 connected to each other. The bottom end of the cylindrical member 62 is provided with a sway plate 621. The reciprocating drive mechanism 61 drives the cylindrical member 62 to reciprocate in a direction perpendicular to the bottom surface of the experimental flow channel 4.
[0029] Preferably, the first pump 101, the second pump 102, the third pump 103, the fourth pump 104, and the fifth pump 105 are all peristaltic pumps.
[0030] Preferably, all bends in the connecting pipes used in the experimental apparatus employ elbow structures with a radius of curvature greater than or equal to 5 times the pipe diameter. With radius of curvature R and pipe diameter D, the condition R ≥ 5D is met. Furthermore, flow control limits the local shear stress throughout the entire process to below 0.1 Pa, ensuring that the *Noctiluca scintillans* solution does not exhibit unpredictable luminescence during the "cultivation-experiment-recovery" modules. This step, as a physical safeguard, effectively extends the effective operating time of a single batch of tracer.
[0031] Preferably, the LED light source 1 is an array-type full-spectrum adjustable LED lamp array, the Noctiluca scintillans culture dish 2 is provided with a nutrient salt replenishment port 21, and the light-shielding container 7 is provided with a nutrient salt replenishment port 71.
[0032] The imaging device 5 needs to be a high-sensitivity, low-illuminance imaging device. Preferably, the imaging device 5 is an EMCCD (electron multiplier charge-coupled device) camera or an sCMOS (scientific-grade complementary metal-oxide-semiconductor) camera, and the minimum detectable light intensity of the imaging device 5 is no higher than 1×10⁻⁶. -6 The quantum efficiency is no less than 80% to ensure stable recording of the transient bioluminescent signals generated by Noctiluca scintillans under shear stimulation. This process eliminates optical occlusion and reflection interference from solid boundaries through the bioluminescence properties, achieving accurate recording of the near-wall flow field evolution phase.
[0033] The flow field visualization experimental device based on Noctiluca scintillans biological solution further includes a PLC controller 10, which is connected to a first transfer pump 101, a second transfer pump 102, a third transfer pump 103, a fourth transfer pump 104, a fifth transfer pump 105 and a biological activity calibration unit 9.
[0034] The aforementioned flow field visualization experimental device based on Noctiluca scintillans biological solution further includes a PLC controller 10. The PLC controller 10 is connected to a first transfer pump 101, a second transfer pump 102, a third transfer pump 103, a fourth transfer pump 104, a fifth transfer pump 105, and a biological activity calibration unit 9. The PLC controller 10 is preset with thresholds for the luminescence intensity of the Noctiluca scintillans solution to meet the experimental luminescence intensity and thresholds for the peak luminescence attenuation rate of Noctiluca scintillans to meet the flow field visualization experiment. The preferred threshold for the peak luminescence attenuation rate of Noctiluca scintillans is 20%.
[0035] The working principle of the flow field visualization experimental device based on Noctiluca scintillans biological solution described in this invention is as follows: First, the light-dark rhythm of LED light source 1 (12h light / 12h darkness) is controlled, and the temperature of the Noctiluca scintillans solution in the Noctiluca scintillans culture dish 2 is adjusted to 18-22℃, the salinity is maintained at 28-32 PSU, and the pH value is maintained at 8.0-8.2, inducing Noctiluca scintillans to enter a high-activity growth phase. The above parameters are adjusted in the following ways: temperature adjustment relies on the heat generated by LED light source 1 to compensate for the balance; salinity and pH value are adjusted by manually pumping a pre-concentrated conditioning solution (such as artificial sea salt concentrate or NaHCO3 buffer solution) into the nutrient salt replenishment port-21. The bioactivity calibration unit 9 detects the luminescence peak of the Noctiluca scintillans solution and transmits the data to the PLC controller 10. The PLC controller 10 compares the captured luminescence peak with a preset threshold. When the luminescence peak is greater than or equal to the preset threshold, the PLC controller 10 starts the delivery pump 101 to quantitatively pump the Noctiluca scintillans solution into the experimental flow tank 4, and then allows the solution to stand in situ under completely dark conditions. In-situ dark adaptation was performed for 1 minute to completely eliminate residual stress from mechanical stimulation during the pumping process, ensuring that the biological background noise at the start of the experiment did not exceed 1×10⁻⁶. -7 lx. After in-situ dark adaptation is completed, the reciprocating drive mechanism 6 is activated to drive the cylindrical component 62 to move the heave plate 621 in a direction perpendicular to the bottom surface of the experimental flow channel 4, acting on the Noctiluca scintillans solution in the experimental flow channel 4, generating shear layers or vortex structures, and the Noctiluca scintillans produces transient spontaneous emission under mechanical stimulation. This invention utilizes bioactive media as "active tracer particles" to convert the complex flow field physical structure into discrete optical signals with brightness gradients in real time, and uses an EMCCD camera or sCMOS camera to capture the emission sequence images; After a single experimental condition is completed, the experiment can be terminated or the next condition can be started. If the next condition is started, the experimental apparatus enters a dynamic evaluation and sorting procedure. The PLC controller 10 receives the signal of the luminescence peak of the Noctiluca scintillans solution in the experimental flow tank 4 from the bioactivity calibration unit 9 in real time, calculates the luminescence peak attenuation rate of Noctiluca scintillans, and executes a logical judgment: if the luminescence peak attenuation rate of Noctiluca scintillans is less than a preset threshold of 20%, the bioactivity of the Noctiluca scintillans solution is determined to be good, and image acquisition for the next experimental condition continues; if the luminescence peak attenuation rate of Noctiluca scintillans is greater than or equal to the preset threshold of 20%, the PLC controller 10 starts the transfer pump 102 to pump the Noctiluca scintillans solution into the light-shielding tank 7, and manually or automatically adds a trace amount of fresh nutrients through the nutrient replenishment port 71, so that the Noctiluca scintillans can perform a short-term experiment for 20 minutes in a completely light-shielded environment. Physiological dormancy is initiated to promote the polarization reset of cell membrane potential and the synthesis of luminescent substrates. After the dormancy period ends, the PLC controller 10 receives the signal of the luminescence peak value of the Noctiluca scintillans solution in the light-shielding tank 7 from the bioactivity calibration unit 9 in real time, calculates the luminescence peak attenuation rate of Noctiluca scintillans and executes logical judgment: if the luminescence peak attenuation rate of Noctiluca scintillans is less than the preset threshold of 20%, it is determined that the physiological refractory period has been eliminated, and the PLC controller 10 starts the transfer pump 3 103 to pump the Noctiluca scintillans solution into the light-shielding tank 7 for the next working condition experiment, completing the high-frequency small-cycle reuse path; if the luminescence peak attenuation rate of Noctiluca scintillans is still greater than or equal to the preset threshold of 20%, it is determined that the batch of media has serious physiological loss, and the PLC controller 10 starts the transfer pump 4 104 to pump the Noctiluca scintillans solution into the biological solution storage tank 8 for temporary storage. Furthermore, to ensure the continuity of the flow field experiment, the PLC controller 10 starts the delivery pump 101 to replenish the experimental flow tank 4 with fresh Noctiluca scintillans solution that has passed the previous evaluation, and proceeds to the next experimental condition. If multiple cycles of the experiment are required, the dynamic evaluation and sorting procedure and the single-condition experiment are repeated until the cycle of the experiment ends. This invention constructs a closed-loop control system that takes into account bioactivity protection, hydraulic buffer protection, and efficient and continuous experimental operation through the phase correlation and logical coordination between the bioactivity calibration unit 9 and the PLC controller 10. After the experiment, the experimental setup entered the "full return" mode. PLC controller 10 activated transfer pump 102, pumping all the *Noctiluca scintillans* solution from experimental flow tank 4 into the light-shielding tank 7. A small amount of fresh nutrients was manually or automatically added through nutrient replenishment port 71, allowing the *Noctiluca scintillans* to undergo a 20-minute "light-shielding rest" in a completely dark environment. This resting time allowed the *Noctiluca scintillans*, which was in a "refractory period," to regain its mechanical sensitivity. After the rest period, PLC controller 10 drove transfer pump 104 to return all the *Noctiluca scintillans* solution in the light-shielding tank 7 to the biological solution storage tank 8. Then, transfer pump 105 was activated to return all the *Noctiluca scintillans* solution in the biological solution storage tank 8 (including the *Noctiluca scintillans* solution previously determined to have severe physiological depletion) to the culture module, ending the use of the experimental setup. This invention utilizes the light-shielding container 7 as a physiological buffer zone to avoid the negative impact of the Noctiluca scintillans solution containing experimental residual stress and metabolic waste on the stable population in the Noctiluca scintillans culture dish 2. This design ensures that the mechanical fatigue generated during the experiment does not directly impact the culture reference environment, realizes the sustainable and engineered circulation of the tracer medium, and guarantees the constant tracer concentration and long-term operational reliability of the system.
[0036] An experimental method for flow field visualization, using the aforementioned flow field visualization experimental device based on Noctiluca scintillans biosolution, specifically includes the following steps: S1. Directed cultivation of tracer medium: Control the light-dark rhythm of LED light source 1, adjust the temperature of Noctiluca scintillans solution, and adjust the salinity and pH value of Noctiluca scintillans solution by filling Noctiluca scintillans culture dish 2 with artificial sea salt concentrate or pH buffer solution to induce Noctiluca scintillans to enter a high-activity growth period. S2. Pre-evaluation of tracer medium status and in-situ excitation: The luminescence peak of the Noctiluca scintillans solution in the Noctiluca scintillans culture dish 2 is detected by the bioactivity calibration unit 9. When the preset threshold T1 is reached, the transfer pump 101 is started to pump the Noctiluca scintillans solution quantitatively into the experimental flow tank 4. Then, the transfer pump 101 is turned off and the solution is left to stand for a predetermined time H1 to allow Noctiluca scintillans to undergo physiological dormancy in a completely dark environment, so as to promote the polarization reset of cell membrane potential and the synthesis of luminescent substrate. S3. Perform optical conversion of flow field characteristics: Set the motion state of the flow field excitation model 6, specifically the stroke, number of reciprocations, speed, power, etc., start the flow field excitation model 6, apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel 4, and then turn off the flow field excitation model 6. During this period, capture the luminescence sequence image through the imaging device 5. S4. Consider whether to repeat the experiment: Decide whether to conduct the flow field visualization experiment for the next working condition. If so, continue to the next step; if not, start the second transfer pump 102, and pump the Noctiluca scintillans solution into the light-shielding tank 7 through the first pipe. Then, turn off the second transfer pump 102, add trace nutrients to the Noctiluca scintillans solution in the light-shielding tank 7, and let it stand for the predetermined time H2. After the standing time is completed, start the fourth transfer pump 104, and pump the Noctiluca scintillans solution in the light-shielding tank 7 into the biological solution storage tank 8. Then, turn off the fourth transfer pump 104, and then start the fifth transfer pump 105, and pump the Noctiluca scintillans solution in the biological solution storage tank 8 into the Noctiluca scintillans culture dish 2. Then, turn off the fifth transfer pump 105 and end the experiment. S5. Preliminary activity detection and intelligent sorting: The luminescence peak of the Noctiluca scintillans solution in the experimental flow tank 4 is detected by the bioactivity calibration unit 9. If the luminescence peak decay rate is less than the preset threshold T2, it is determined that the bioactivity is good, and step S3 is executed; if the luminescence peak decay rate is greater than or equal to the preset threshold T2, the next step is continued. S6. Secondary detection and intelligent sorting after activity recovery: Pump 2 (102) is started, and the *Noctiluca scintillans* solution is directionally pumped into the light-shielding tank 7 through pipe 1. Pump 2 (102) is then turned off, and nutrients are added to the *Noctiluca scintillans* solution in the light-shielding tank 7. The solution is then allowed to stand for a predetermined time (H3) to allow the *Noctiluca scintillans* to undergo physiological dormancy in a completely dark environment, promoting the polarization reset of cell membrane potential and the synthesis of luminescent substrates. After standing, the luminescence peak value of the *Noctiluca scintillans* solution in the light-shielding tank 7 is detected by the bioactivity calibration unit (9). If the luminescence peak decay rate is less than the preset threshold (T2), it is determined that the physiological refractory period has been eliminated, and pump 3 (3) is started. 103. After pumping the Noctiluca scintillans solution in the light-shielding tank 7 into the experimental flow tank 4 through pipe 2, turn off the transfer pump 3 103 and execute step S3. If the displayed luminescence peak attenuation rate is greater than or equal to the preset threshold T2, it is determined that the batch of Noctiluca scintillans solution has serious physiological loss. Then, start the transfer pump 4 104 to pump the experimental solution in the light-shielding tank 7 into the biological solution storage tank 8, turn off the transfer pump 4 104, and then start the transfer pump 1 101 to quantitatively pump the Noctiluca scintillans solution in the Noctiluca scintillans culture dish 2 into the experimental flow tank 4. Then, turn off the transfer pump 1 101 and let it stand for a predetermined time H1. After the standing time is completed, execute step S3.
[0037] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.
Claims
1. A flow field visualization experimental device based on Noctiluca scintillans bio-solution, characterized in that, It includes a biological solution culture module, a flow field experiment module, a biological activity recovery module, a biological solution storage tank (8), and a biological activity calibration unit (9); The biological solution culture module includes an LED light source (1) and a Noctiluca scintillans culture dish (2). The LED light source (1) is positioned above the Noctiluca scintillans culture dish (2), which is filled with Noctiluca scintillans solution. The flow field experimental module includes an experimental darkroom (3), an experimental flow channel (4), an imaging device (5), and a flow field excitation model (6) arranged in the experimental darkroom (3). The experimental flow channel (4) is connected to the Noctiluca scintillans culture dish (2), and a delivery pump (101) is provided on the pipe between the two. The imaging device (5) faces the experimental flow channel (4), and the flow field excitation model (6) is located above the experimental flow channel (4) and is used to apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel (4) to make the Noctiluca scintillans solution glow. The bioactivity recovery module includes a light-shielding tank (7), which is connected to the experimental flow tank (4) through pipe one and pipe two. Pipe one is equipped with a second delivery pump (102), and pipe two is equipped with a third delivery pump (103). The biological solution storage tank (8) is connected to the light-shielding tank (7), and a four-way pump (104) is installed on the pipe between the two. The biological solution storage tank (8) is also connected to the Noctiluca scintillans culture dish (2), and a five-way pump (105) is installed on the pipe between the two. The Noctiluca scintillans culture dish (2), experimental flow tank (4), and light-shielding container (7) are all equipped with a bioactivity calibration unit (9) for detecting the luminescence peak of the Noctiluca scintillans solution.
2. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, The bioactivity calibration unit (9) includes a sampling pump (91), a detection channel, a mechanical stimulation component (92), a PMT photomultiplier module (93), and a light-shielding shell (94). The sampling pump (91) is connected to the detection channel. The mechanical stimulation component (92) is built into the detection channel and a light-shielding shell (94) is installed on the outside. The mechanical stimulation component (92) is a geometrically induced structure. The PMT photomultiplier module (93) is arranged radially on the mechanical stimulation component (92) and connected to the light-shielding shell (94).
3. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 2, characterized in that, The mechanical stimulation component (92) is a contraction-expansion nozzle or a throttling orifice plate with a fixed pressure drop.
4. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, The flow field excitation model (6) includes a reciprocating drive mechanism (61) and a cylindrical component (62). The bottom end of the cylindrical component (62) is provided with a heave plate (621). The reciprocating drive mechanism (61) drives the cylindrical component (62) to reciprocate in a direction perpendicular to the bottom surface of the experimental flow channel (4).
5. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, The first (101), second (102), third (103), fourth (104) and fifth (105) of the pumps are all peristaltic pumps.
6. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, All bends in the connecting pipes used in the experimental setup employ elbow structures with a radius of curvature greater than or equal to 5 times the pipe diameter.
7. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, The LED light source (1) is an array of full-spectrum adjustable LED lamps. The Noctiluca scintillans culture dish (2) is provided with a nutrient salt replenishment port one (21), and the light-shielding container (7) is provided with a nutrient salt replenishment port two (71).
8. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, The imaging device (5) is an EMCCD or sCMOS camera.
9. The flow field visualization experimental device based on Noctiluca scintillans biosol as described in claim 1, characterized in that, It also includes a PLC controller (10), which is connected to the first transfer pump (101), the second transfer pump (102), the third transfer pump (103), the fourth transfer pump (104), the fifth transfer pump (105) and the bioactivity calibration unit (9).
10. An experimental method for visualizing flow fields, characterized in that, The flow field visualization experimental device based on Noctiluca scintillans biosol as described in any one of claims 1-9 specifically includes the following steps: S1. Directional culture of tracer medium: control the light-dark rhythm of LED light source (1), adjust the temperature of Noctiluca scintillans solution, and adjust the salinity and pH value of Noctiluca scintillans solution by filling Noctiluca scintillans culture dish (2) with artificial sea salt concentrate or pH buffer solution, so as to induce Noctiluca scintillans to enter a high-activity growth period. S2, Pre-evaluation of tracer medium status and in-situ excitation: The luminescence peak of the Noctiluca scintillans solution in the Noctiluca scintillans culture dish (2) is detected by the bioactivity calibration unit (9). When the preset threshold T1 is reached, the transfer pump 1 (101) is started to pump the Noctiluca scintillans solution quantitatively into the experimental flow tank (4). Then the transfer pump 1 (101) is turned off and the solution is left to stand for a predetermined time H1. S3. Perform optical conversion of flow field characteristics: Set the motion state of the flow field excitation model (6), start the flow field excitation model (6), apply mechanical stimulation to the Noctiluca scintillans solution in the experimental flow channel (4), and then close the flow field excitation model (6). During this period, capture the luminescence sequence image through the imaging device (5). S4. Consider whether to repeat the experiment: Decide whether to conduct the flow field visualization experiment for the next working condition. If so, continue to the next step; if not, start the second transfer pump (102), pump the Noctiluca scintillans solution into the light-shielding tank (7) through the first pipe, then turn off the second transfer pump (102), add nutrients to the Noctiluca scintillans solution in the light-shielding tank (7), and let it stand for the predetermined time H2. After the standing time is over, start the fourth transfer pump (104), pump the Noctiluca scintillans solution in the light-shielding tank (7) into the biological solution storage tank (8), then turn off the fourth transfer pump (104), then start the fifth transfer pump (105), pump the Noctiluca scintillans solution in the biological solution storage tank (8) into the Noctiluca scintillans culture dish (2), then turn off the fifth transfer pump (105) and end the experiment. S5. Preliminary activity detection and intelligent sorting: The luminescence peak of the Noctiluca scintillans solution in the experimental flow tank (4) is detected by the bioactivity calibration unit (9). If the luminescence peak decay rate is less than the preset threshold T2, then step S3 is executed; if the luminescence peak decay rate is greater than or equal to the preset threshold T2, then the next step is continued. S6. Secondary detection and intelligent sorting after activity recovery: Start the second transfer pump (102) and pump the Noctiluca scintillans solution into the light-shielding tank (7) through the first pipe. Then, turn off the second transfer pump (102), add nutrients to the Noctiluca scintillans solution in the light-shielding tank (7), and let it stand for a predetermined time H3. After the standing time is completed, the bioactivity calibration unit (9) detects the luminescence peak of the Noctiluca scintillans solution in the light-shielding tank (7). If the luminescence peak decay rate is less than the preset threshold T2, start the third transfer pump (103) and pump the Noctiluca scintillans solution in the light-shielding tank (7) through the second pipe. After the algal solution is directionally pumped into the experimental flow tank (4), the third transfer pump (103) is turned off and step S3 is executed. If the emission peak attenuation rate is greater than or equal to the preset threshold T2, the fourth transfer pump (104) is started to pump the experimental solution in the light shield (7) into the biological solution storage tank (8). Then the fourth transfer pump (104) is turned off, and the first transfer pump (101) is started to quantitatively pump the Noctiluca scintillans solution in the Noctiluca scintillans culture dish (2) into the experimental flow tank (4). Then the first transfer pump (101) is turned off and the solution is allowed to stand for a predetermined time H1. After the standing time is completed, step S3 is executed.