Pump-driven two-phase flow cooling control method based on precise temperature control

Abstract

The application discloses a pump-driven two-phase flow cooling control method based on precise temperature control and belongs to the technical field of phase change heat dissipation control. The method comprises the following steps: determining a target saturation pressure according to a target evaporation saturation temperature, and performing temperature-pressure coordinated regulation on a working medium in a liquid accumulator to reach a gas-liquid two-phase saturation state; adjusting the working medium entering an evaporator through a preheater to reach a preset inlet thermodynamic state; collecting evaporator operation parameters and determining outlet real-time dryness; comparing the outlet real-time dryness with a target dryness range to obtain a dryness deviation; and based on the dryness deviation and the operation parameters, performing multivariable coordinated feedback control on the flow, inlet temperature and saturation state of the circulating working medium, so that the evaporation saturation temperature and the outlet dryness are kept within the target range. The application takes the outlet dryness as an active feedback variable to participate in closed-loop regulation and control, realizes multicontroller coordinated decision-making, suppresses evaporation temperature drift and dryness oscillation, and is suitable for precise temperature control scenes of high heat flux density equipment.

Description

Technical Field

[0001] This invention relates to the field of two-phase flow cooling control technology, specifically a pump-driven two-phase flow cooling control method based on precise temperature control. Background Technology

[0002] Currently, pump-driven two-phase flow cooling technology, which uses mechanical pumps to drive the phase change working fluid to circulate in a closed loop, is considered an effective way to solve the problem of heat dissipation in high heat flux density systems. These systems rely on a sensing network constructed from various types of sensors, including temperature, pressure, and flow rate sensors, and regulate loop pressure and working fluid flow rate by adjusting pump speed and valve opening. Theoretically, they can utilize the latent heat of phase change to achieve efficient heat transport. However, in practical engineering applications, there is a strong nonlinear coupling relationship between evaporation saturation temperature, saturation pressure, working fluid inlet thermodynamic state, mass flow rate, and outlet dryness fraction. Existing control strategies generally treat these parameters as independent adjustment channels, employing incompletely decoupled PID hierarchical control for independent tuning. This fragmented approach ignores the inherent linkage mechanism of various thermodynamic parameters during the phase change process, making it difficult for the system to coordinately optimize the receiver temperature and pressure, evaporator inlet state, and circulation flow rate according to the target evaporation state. This limits further improvement in control accuracy.

[0003] More critically, the evaporator outlet dryness fraction, a core parameter directly reflecting the degree of phase change heat completion and system safety margin, has long been relegated to a subordinate position in existing control systems. In most engineering practices, the outlet dryness fraction signal is only used for extreme state alarms or post-fault analysis, and is not introduced into the real-time closed-loop control loop as an active feedback variable, failing to integrate multi-source information with temperature, pressure, and flow signals. This design flaw prevents the system from promptly sensing the dynamic shift in the gas-liquid two-phase ratio within the evaporator under conditions such as step changes in heat load, cold source temperature disturbances, or deviations in working fluid charge. The controller can only passively correct based on the lag response of temperature or pressure, which not only weakens the system's dynamic response speed but also makes evaporation temperature drift and severe oscillations in outlet dryness fraction frequent common problems, seriously threatening temperature control stability and equipment operational safety.

[0004] Furthermore, existing control methods lack the ability to adaptively track the thermodynamic equilibrium point of the system under all operating conditions when facing wide-range variable heat loads and varied environmental conditions. Since the thermodynamic state regulation of the liquid reservoir, the control of inlet subcooling, and the regulation of mass flow rate belong to different actuators with significant differences in time constants, existing strategies often exhibit conflicting action directions or mismatched adjustment amplitudes after disturbances occur. This can easily induce malignant instabilities such as two-phase flow oscillations, local dry burning, or even pump cavitation. At the same time, the inherent hysteresis of feedback regulation makes it difficult for the system to recover to the target evaporation temperature range within a limited time under severe thermal shocks. The cumulative effect of temperature control deviation is significant, which cannot meet the urgent needs of high-power electronic devices, laser weapons, and aerospace thermal control for high-precision temperature control and long-term reliable operation. Therefore, innovation at the control architecture level is urgently needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a pump-driven two-phase flow cooling control method based on precise temperature control, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a pump-driven two-phase flow cooling control method based on precise temperature control, comprising the following steps:

[0007] Step 1: Obtain the target evaporation saturation temperature, determine the corresponding target saturation pressure based on the temperature-saturation pressure relationship of the circulating working fluid, and adjust the temperature and pressure of the circulating working fluid in the reservoir in a coordinated manner based on the target saturation pressure so that the circulating working fluid reaches the target gas-liquid two-phase saturation state. Step 2: Based on the target gas-liquid two-phase saturation state formed in Step 1, drive the circulating working fluid to circulate, and adjust the heating power of the preheater according to the target evaporation saturation temperature and the mass flow rate of the circulating working fluid, so that the circulating working fluid entering the evaporator reaches the preset inlet thermal state. Step 3: The circulating working fluid adjusted in Step 2 is delivered to the evaporator to absorb the heat of the object being cooled, and the temperature, pressure and mass flow rate parameters during the operation of the evaporator are collected to obtain the real-time operating status parameters of the circulating working fluid. Step 4: Based on the real-time operating status parameters obtained in Step 3 and the effective heat absorbed by the circulating working fluid, determine the real-time dryness of the circulating working fluid at the evaporator outlet, and determine the dryness deviation of the real-time dryness relative to the target dryness range. Step 5: Based on the dryness deviation determined in Step 4 and the real-time operating status parameters obtained in Step 3, perform coordinated feedback control on the flow rate adjustment, inlet temperature adjustment, and saturation state adjustment of the circulating working fluid to keep the evaporation saturation temperature and evaporator outlet dryness within the corresponding target range.

[0008] This invention solves the parameter mismatch problem caused by independent adjustment of temperature, pressure and flow rate in the prior art by constructing a three-level series control architecture of "coordinated adjustment of saturated state of liquid receiver - tuning of thermal state of preheater inlet - active feedback of dryness of evaporator outlet". The method first determines the saturation pressure in reverse according to the target evaporation temperature and actively adjusts the saturated state of the liquid receiver in both gas and liquid phases. Then, it performs fine compensation of the inlet thermal state through the preheater. In particular, the outlet dryness is introduced as an active feedback variable into the closed-loop control, breaking the technical bias of using it only for passive monitoring. The comprehensive application of the above methods enables the system to simultaneously suppress evaporation temperature drift and outlet dryness oscillation within a wide range of heat load fluctuations, improving temperature control accuracy and operational stability.

[0009] Preferably, in step 1, the temperature and pressure of the circulating working fluid in the reservoir are regulated in a coordinated manner, including: collecting the actual temperatures at multiple temperature measurement points within the reservoir; determining the equivalent temperature of the reservoir based on the deviation of each actual temperature from the median temperature and the historical temperature fluctuation at each measurement point; and determining the saturation deviation based on the equivalent temperature, the actual pressure of the reservoir, the target evaporation saturation temperature, and the target saturation pressure. This scheme determines the equivalent temperature by collecting data from multiple temperature measurement points in the reservoir and constructing a weighted fusion model based on the degree of temperature outlier and the historical fluctuation amplitude, avoiding misjudgments caused by local disturbances or sensor noise in single-point temperature measurement. The proposed saturation deviation integrates information from three dimensions: pressure deviation, temperature deviation, and internal temperature non-uniformity, providing a precise quantitative decision-making basis for subsequent charging and discharging regulation, and improving the resolution and anti-interference capability of the reservoir saturation regulation.

[0010] Preferably, in step 1, the inflation / deflation adjustment amount of the reservoir's gasbag is determined based on the pressure deviation between the actual pressure of the reservoir and the target saturation pressure, and the temperature deviation between the equivalent temperature of the reservoir and the target evaporation saturation temperature. The heating power of multiple heating units located at different positions in the reservoir is determined based on the actual temperature at each temperature measurement location. This scheme achieves coordinated control of pressure and temperature by coupling pressure and temperature deviations into the same inflation / deflation adjustment formula, avoiding action conflicts during independent adjustment. Simultaneously, a multi-point heating power allocation model integrating target temperature tracking, local homogenization, and coupled compensation is constructed, enabling refined active control of the internal temperature field of the reservoir. This dual-coordinated strategy shortens the transition time for the reservoir to return to the target saturation state and suppresses internal thermal stratification.

[0011] Preferably, the preset inlet thermal state in step 2 is a saturated liquid phase or a liquid phase with a target subcooling. The target subcooling is determined based on the current heat load of the object being cooled, the mass flow rate of the circulating working fluid, and the latent heat of vaporization of the circulating working fluid in the current saturated state. This ensures that the circulating working fluid is fully preheated before entering the evaporator and does not undergo a phase change. This invention dynamically determines the target subcooling by introducing a phase change load coefficient, allowing the inlet thermal state to adaptively adjust according to the real-time heat load. The S-shaped mapping relationship ensures the smoothness of the subcooling adjustment. Combined with high-precision closed-loop feedback of the preheater outlet temperature, the working fluid entering the evaporator is always stably maintained in a saturated liquid phase or a liquid phase with precise subcooling, thus guaranteeing the stability and controllability of the phase change heat transfer process within the evaporator from the source.

[0012] Preferably, the speed of the circulating pump is nonlinearly iteratively adjusted based on the flow deviation between the real-time mass flow rate of the circulating working fluid and the target mass flow rate, as well as the dryness deviation between the real-time dryness of the evaporator outlet and the target dryness. This scheme breaks through the traditional single flow deviation feedback mode, nonlinearly integrating the outlet dryness deviation and the flow deviation to construct an exponential iterative speed adjustment strategy that combines flow regulation and dryness correction. This enables rapid convergence of large deviations and fine-tuning of small deviations, making the circulating pump an active participant in dryness control and suppressing drastic fluctuations in outlet dryness when the heat load changes.

[0013] Preferably, in step 3, the evaporator inlet temperature, evaporator outlet temperature, evaporator inlet pressure, evaporator outlet pressure, evaporator inlet-outlet pressure difference, and circulating working fluid mass flow rate are constructed into a real-time operating state vector. The evaporator thermodynamic state deviation index is determined based on the normalized deviation of each operating parameter in the real-time operating state vector relative to the corresponding reference state value. The temperature, pressure, and mass flow rate are collected via thermocouples, pressure sensors, and mass flow meters, respectively. This scheme constructs a six-dimensional operating state vector covering the temperature, pressure, and flow fields, and comprehensively determines the thermodynamic state deviation index based on the normalized deviation of each parameter and the nonlinear sensitivity index. This achieves a single-value quantitative assessment of the overall thermodynamic health status of the evaporator. The aforementioned indicators are comparable across operating conditions and systems, solving the problems of fragmented operating state perception and lack of comprehensive assessment methods in traditional methods.

[0014] Preferably, in step 4, the effective heat absorption power of the circulating working fluid for phase change is determined based on the input heat power of the evaporator, the pre-calibrated system heat loss, and the inlet specific enthalpy of the circulating working fluid entering the evaporator. The real-time dryness of the evaporator outlet is then determined based on the effective heat absorption power, the circulating working fluid mass flow rate, and the thermophysical parameters corresponding to the current evaporation pressure. This invention introduces a polynomial heat loss fitting model obtained through calibration experiments to accurately deduct system losses, making the calculation accuracy of the effective heat absorption power significantly better than the simple electrical power input method. Furthermore, this model accurately reflects the nonlinear variation of heat loss under different heat loads. Combined with the thermophysical parameters corresponding to the evaporation pressure, it achieves accurate thermodynamic calculation of the outlet dryness, ensuring the reliability and real-time performance of the dryness information in closed-loop control.

[0015] Preferably, the real-time dryness at the evaporator outlet is compared with the target dryness range defined by the lower and upper limits of the target dryness, and the dryness feedback flow correction amount is determined based on the direction and degree of deviation of the real-time dryness from the target dryness range. This scheme constructs a dryness deviation determination method with dead-zone characteristics: the deviation is zero when the dryness is within the target range, avoiding frequent control switching caused by small fluctuations in dryness near the target value. Combined with a sign-function type flow correction amount with a nonlinear sensitivity index and compressibility coefficient, the flow correction can be adaptively determined based on the direction and degree of dryness exceeding the limit, ensuring stable dryness within the target range while also possessing rapid correction capability when exceeding the limit.

[0016] Preferably, in step 5, a control error vector is constructed based on the evaporator outlet dryness deviation, evaporator inlet temperature deviation, and evaporation saturation temperature deviation. Based on the sensitivity of the circulating pump, preheater, and receiver to each control error, the circulating pump speed adjustment, preheater heating power adjustment, and receiver temperature and pressure coordinated adjustment are determined. The receiver temperature and pressure coordinated adjustment is further converted into receiver gasbag filling and venting adjustment and receiver heating power adjustment, so that the outlet dryness, inlet thermal state, and evaporation saturation state converge synchronously to their respective target values. This invention, by constructing a three-dimensional control error vector and establishing a state sensitivity matrix, uses a regularized least squares method to solve for the synchronous adjustment of the circulating pump speed, preheater power, and receiver temperature and pressure state, achieving globally optimal collaborative decision-making across multiple execution channels. By quantifying the contribution capabilities of each actuator to different control objectives and seeking the optimal allocation of adjustment amounts, it avoids conflicts or mismatches in the actions of multiple actuators, enabling the outlet dryness, inlet thermal state, and evaporation saturation temperature to converge synchronously.

[0017] Preferably, the gas-liquid two-phase circulating working fluid output from the evaporator is sequentially passed through a regenerator and a plate condenser for exothermic condensation. The target heat transfer power on the condensing side is determined based on the real-time dryness of the evaporator outlet, the mass flow rate of the circulating working fluid, the condenser outlet temperature, and the target condensation outlet temperature. The chiller's refrigeration output is adjusted according to the target heat transfer power on the condensing side to maintain the circulating working fluid output from the condenser in a preset liquid phase state. This invention achieves real-time matching between condensation demand and the evaporator-side operating state by constructing a heat transfer power model that integrates outlet dryness, mass flow rate, condensation outlet temperature deviation, and nonlinear compensation factors, ensuring sufficient compensation on the condensing side when deviations are large. Combined with the safety margin conversion of the chiller's refrigeration power, the condenser output always maintains a preset liquid phase state, establishing a complete control chain from active control on the evaporator side to adaptive response on the condensing side, achieving closed-loop management of the entire system's thermal state.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention determines the target saturation pressure by targeting the evaporation saturation temperature, and combines the actual temperature and pressure of the liquid reservoir for coordinated temperature and pressure regulation, so that the circulating working fluid can stably establish and maintain the target gas-liquid two-phase saturation state. Compared with the method of controlling temperature or pressure alone, it can reduce the mutual interference between temperature and pressure regulation and improve the control accuracy and stability of the evaporation saturation temperature.

[0019] 2. The present invention adjusts the heating power of the preheater according to the target evaporation saturation temperature and the mass flow rate of the circulating working fluid, so that the circulating working fluid entering the evaporator maintains the preset inlet thermal state. This allows for dynamic adjustment of the evaporator inlet temperature according to the actual operating conditions, reducing the impact of inlet temperature fluctuations or premature phase change on the evaporation heat exchange process, and improving the stability of the two-phase flow formation process and the controllability of the cooling process.

[0020] 3. This invention collects real-time operating parameters such as temperature, pressure, and mass flow rate of the evaporator and determines the real-time dryness of the evaporator outlet by combining the effective heat absorbed by the circulating working fluid. This transforms the outlet dryness from a traditional state monitoring parameter into a feedback control parameter, which can adjust the circulating working fluid flow rate and inlet thermal state in a timely manner according to the dryness deviation. This reduces the risk of local drying or dry burning caused by excessively high outlet dryness and improves the safety and stability of the evaporator heat exchange process.

[0021] 4. The present invention further uses the outlet dryness, evaporator inlet temperature and evaporation saturation temperature as the basis for coordinated feedback to link the adjustment of the circulating pump, preheater and liquid receiver, so that the flow rate adjustment, inlet temperature adjustment and saturation state adjustment cooperate with each other. This can quickly correct the system operating state when the heat load changes, reduce the fluctuation of evaporation temperature and outlet dryness, thereby improving the adaptability of the pump-driven two-phase flow cooling system to changing operating conditions and the overall temperature control stability. Attached Figure Description

[0022] Figure 1 This is an overall flowchart of a pump-driven two-phase flow cooling control method based on precise temperature control according to the present invention. Figure 2 This is a flowchart of the control logic of the present invention; Figure 3 This is a schematic block diagram of the system structure formed by the control method of the present invention; Figure 4 This is a block diagram illustrating the principle of temperature and pressure coordinated regulation of the liquid reservoir in this invention. Figure 5 This is a block diagram illustrating the principle of outlet dryness feedback regulation in this invention. Figure 6 This is a schematic diagram illustrating the principle of adaptive supercooling adjustment in this invention; Figure 7 This is a block diagram illustrating the dynamic matching control principle on the condenser side in this invention. Figure 8 This is a schematic diagram of the pump-driven two-phase flow cooling system of the present invention. Detailed Implementation

[0023] To enable those skilled in the art to understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0024] The present invention will now be described in detail with reference to the accompanying drawings: Example: like Figures 1-8 As shown, this embodiment of the invention provides a pump-driven two-phase flow cooling control method based on precise temperature control, comprising the following steps: Step 1: Obtain the target evaporation saturation temperature, determine the corresponding target saturation pressure based on the temperature-saturation pressure relationship of the circulating working fluid, and adjust the temperature and pressure of the circulating working fluid in the reservoir in a coordinated manner based on the target saturation pressure so that the circulating working fluid reaches the target gas-liquid two-phase saturation state. Step 2: Based on the target gas-liquid two-phase saturation state formed in Step 1, drive the circulating working fluid to circulate, and adjust the heating power of the preheater according to the target evaporation saturation temperature and the mass flow rate of the circulating working fluid, so that the circulating working fluid entering the evaporator reaches the preset inlet thermal state. Step 3: The circulating working fluid adjusted in Step 2 is delivered to the evaporator to absorb the heat of the object being cooled, and the temperature, pressure and mass flow rate parameters during the operation of the evaporator are collected to obtain the real-time operating status parameters of the circulating working fluid. Step 4: Based on the real-time operating status parameters obtained in Step 3 and the effective heat absorbed by the circulating working fluid, determine the real-time dryness of the circulating working fluid at the evaporator outlet, and determine the dryness deviation of the real-time dryness relative to the target dryness range. Step 5: Based on the dryness deviation determined in Step 4 and the real-time operating status parameters obtained in Step 3, perform coordinated feedback control on the flow rate adjustment, inlet temperature adjustment, and saturation state adjustment of the circulating working fluid to keep the evaporation saturation temperature and evaporator outlet dryness within the corresponding target range.

[0025] In step 1, the temperature and pressure of the circulating working fluid in the reservoir are regulated in a coordinated manner, including: collecting the actual temperature corresponding to multiple temperature measuring positions in the reservoir, determining the equivalent temperature of the reservoir based on the degree of deviation of each actual temperature from the median temperature and the degree of historical temperature fluctuation corresponding to each temperature measuring position, and determining the deviation of the saturation state based on the equivalent temperature of the reservoir, the actual pressure of the reservoir, the target evaporation saturation temperature and the target saturation pressure. The equivalent temperature of the reservoir is: , The deviation from saturation is: , in, The equivalent temperature of the liquid reservoir; For the first The actual temperature at each temperature measurement location; The median temperature corresponding to the actual temperature at multiple temperature measurement locations; This refers to the number of temperature measurement locations; For the first The standard deviation of temperature at each temperature measurement location within a preset historical time window; The temperature anomaly decay scale; To prevent temperature weighting from calculating non-zero correction amounts where the denominator is zero; This is the actual pressure of the reservoir; The target saturation pressure; The target evaporation saturation temperature; This serves as the normalized baseline value for pressure. This is the temperature normalized reference value; and These represent the highest and lowest actual temperatures at multiple temperature measurement locations; This is the temperature deviation weighting coefficient; This is the weighting coefficient for temperature non-uniformity.

[0026] In step 1, the inflation and deflation adjustment amount of the reservoir bladder is determined based on the pressure deviation between the actual pressure of the reservoir and the target saturation pressure, and the temperature deviation between the equivalent temperature of the reservoir and the target evaporation saturation temperature. The heating power of multiple heating units set at different positions of the reservoir is determined based on the actual temperature corresponding to each temperature measurement position. The inflation / deflation adjustment range is: , when When the value is >0, nitrogen gas is introduced into the reservoir's gas bladder; when When <0, nitrogen gas is discharged from the reservoir bladder; No. The target heating power corresponding to each heating unit is: , in, The inflation / deflation adjustment amount for the reservoir bladder; The maximum allowable charge / discharge adjustment amount in a single control cycle; This is the pressure deviation adjustment coefficient; This is the coupling adjustment coefficient of temperature deviation on the charging and discharging process; For the first The target heating power of each heating unit; For the first The basic sustaining power of each heating unit; For the first The maximum allowable power of each heating unit; The target temperature tracking coefficient; This is the local temperature homogenization coefficient; This is the coupling compensation coefficient between the overall temperature deviation and the local temperature deviation; This indicates that the corresponding calculation result is limited to an interval. A limiting function within the range.

[0027] Specifically, the target saturation pressure is determined by the target evaporation saturation temperature, and temperature and pressure are coordinated and regulated in combination with the actual temperature and pressure of the liquid reservoir. This enables the circulating working fluid to stably establish and maintain the target gas-liquid two-phase saturation state. Compared with temperature control or pressure control alone, this reduces the mutual interference between temperature and pressure regulation and improves the control accuracy and stability of the evaporation saturation temperature.

[0028] In step 2, the preset inlet thermal state is either a saturated liquid phase state or a liquid phase state with a target subcooling. The target subcooling is determined based on the current heat load of the object being cooled, the mass flow rate of the circulating working fluid, and the latent heat of vaporization of the circulating working fluid in the current saturated state, so that the circulating working fluid is fully preheated before entering the evaporator and does not undergo a phase change. The phase change load factor is defined as: , The target supercooling is: , The target temperature at the evaporator inlet is: , The target heating power of the preheater is: , in, The current heat load of the object being cooled; This refers to the mass flow rate of the circulating working fluid. The latent heat of vaporization of the circulating working fluid under the current saturated state; and These are the preset minimum subcooling and the preset maximum subcooling, respectively; This is the slope coefficient of the supercooling change; This is the reference value for phase change load; The specific heat of the circulating working fluid at constant pressure in the liquid phase; and These are the actual inlet temperature and the actual outlet temperature of the preheater, respectively. This is the preheater outlet temperature feedback compensation coefficient; This is the maximum allowable heating power of the preheater.

[0029] Among them, the preheater is controlled so that the absolute value of the temperature deviation between the preheater outlet temperature and the target temperature at the evaporator inlet is no greater than 0.1℃.

[0030] The speed of the circulating pump is nonlinearly iteratively adjusted based on the flow deviation between the real-time mass flow rate of the circulating working fluid and the target mass flow rate, as well as the dryness deviation between the real-time dryness of the evaporator outlet and the target dryness. No. The target speed of the circulating pump for each control cycle is: , in, For the first The actual speed of the circulating pump in each control cycle; The target speed for the next control cycle; and These are the minimum and maximum permissible speeds of the circulating pump, respectively. For target quality flow rate; For the first Real-time quality flow rate collected in each control cycle; This serves as the baseline value for normalized mass flow rate; For the first Real-time dryness of the evaporator outlet corresponding to each control cycle; Set the dryness value within the target dryness range; This is the baseline value for dryness normalization; This is the mass flow rate feedback coefficient; This is the dryness feedback coefficient.

[0031] Under the design condition of a target evaporation saturation temperature of 60℃, the target mass flow rate is set to be no less than 39.4 g / s, and the circulation pump adjusts the flow rate of the circulating working fluid by changing the speed of the servo motor.

[0032] Specifically, the heating power of the preheater is adjusted according to the target evaporation saturation temperature and the mass flow rate of the circulating working fluid, so that the circulating working fluid entering the evaporator maintains the preset inlet thermal state. This allows for dynamic adjustment of the evaporator inlet temperature according to the actual operating conditions, reducing the impact of inlet temperature fluctuations or premature phase change on the evaporation heat exchange process, and improving the stability of the two-phase flow formation process and the controllability of the cooling process.

[0033] In step 3, the evaporator inlet temperature, evaporator outlet temperature, evaporator inlet pressure, evaporator outlet pressure, evaporator inlet-outlet pressure difference, and circulating working fluid mass flow rate are constructed into a real-time operating state vector, and the evaporator thermodynamic state deviation index is determined based on the normalized deviation of each operating parameter in the real-time operating state vector relative to the corresponding reference state value. The real-time running state vector is: , The thermal state deviation index is: , in, These are the evaporator inlet temperature and the evaporator outlet temperature, respectively. These are the evaporator inlet pressure and the evaporator outlet pressure, respectively. The pressure difference between the inlet and outlet of the evaporator; The first in the real-time running state vector One operating parameter; For the first Reference status values ​​corresponding to each operating parameter; For the first Normalized scale of each operating parameter; For the first The state weights of each operating parameter; For the first Nonlinear sensitivity index of each operating parameter; The number of real-time running status parameters. The evaporator thermal state deviation index is given, and 0 ≤ ... <1.

[0034] Temperature, pressure, and mass flow rate are collected via thermocouples, pressure sensors, and mass flow meters, respectively.

[0035] In step 4, the effective heat absorption power of the circulating working fluid for phase change is determined based on the heat power input to the evaporator, the pre-calibrated system heat loss, and the inlet specific enthalpy when the circulating working fluid enters the evaporator. The real-time dryness of the evaporator outlet is determined based on the effective heat absorption power, the mass flow rate of the circulating working fluid, and the thermophysical parameters corresponding to the current evaporation pressure. The effective heat absorption power is: , in: , The real-time dryness of the evaporator outlet is: , in, The effective heat power absorbed by the circulating working fluid; The heating voltage used to simulate or generate the thermal load on the object being cooled; This corresponds to the heating current; This refers to the temperature of the heat source or the heated wall surface of the evaporator. The ambient temperature; The temperature difference between the heat source and the environment; , and The heat loss fitting coefficient is obtained through the heat loss calibration experiment; This is the nonlinear exponent of heat loss; Evaporation pressure; The specific enthalpy of the circulating working fluid at the evaporator inlet; The enthalpy of the saturated liquid phase corresponding to the evaporation pressure; This represents the latent heat of vaporization corresponding to the evaporation pressure. This means that the calculation result is limited to the range of 0 to 1.

[0036] When the circulating working fluid entering the evaporator is in a saturated pure liquid phase, the following conditions are met: .

[0037] The real-time dryness at the evaporator outlet is compared with the target dryness range defined by the lower and upper limits of the target dryness, and the dryness feedback flow correction amount is determined based on the direction and degree of deviation of the real-time dryness from the target dryness range. The dryness deviation is: , The dryness feedback flow correction is: , in, The target dryness lower limit; This represents the upper limit of the target dryness level. The dryness feedback flow correction scale; This is a nonlinear sensitivity index for dryness deviation; Adjust the compression factor for the flow rate; It is a symbolic function; when When, increase the mass flow rate of the circulating working fluid; when When, reduce the mass flow rate of the circulating working fluid; when At the same time, keep the dryness feedback flow correction amount at zero.

[0038] Specifically, by collecting real-time operating parameters such as temperature, pressure, and mass flow rate of the evaporator, and combining them with the effective heat absorbed by the circulating working fluid, the real-time dryness of the evaporator outlet is determined. This transforms the outlet dryness from a traditional condition monitoring parameter into a feedback control parameter, allowing for timely adjustment of the circulating working fluid flow rate and inlet thermal state based on dryness deviations. This reduces the risk of localized drying or dry burning caused by excessively high outlet dryness, and improves the safety and stability of the evaporator heat exchange process.

[0039] In step 5, a control error vector is constructed based on the evaporator outlet dryness deviation, evaporator inlet temperature deviation, and evaporation saturation temperature deviation. Based on the sensitivity of the circulating pump, preheater, and liquid receiver to each control error, the circulating pump speed adjustment, preheater heating power adjustment, and liquid receiver temperature and pressure coordinated adjustment are determined. The control error vector is: , The adjustment vector to be executed is: , The adjustment vector is determined according to the following formula: , The state sensitivity matrix is ​​as follows: , in, This refers to the speed adjustment of the circulating pump; Adjustment of preheater heating power; It is a combined regulation of the temperature and pressure of the liquid reservoir; The execution cost weight matrix is ​​for the circulating pump, preheater, and liquid receiver. This is the state sensitivity matrix of the actuator relative to the evaporator outlet dryness, evaporator inlet temperature, and evaporation saturation temperature. The regularization coefficient is used. It is a third-order identity matrix; To control the error weighting matrix; , and These represent the influence coefficients of circulating pump speed, preheater heating power, and liquid receiver temperature and pressure coordinated adjustment on evaporator outlet dryness, respectively. , and These represent the influence coefficients of the three execution parameters on the evaporator inlet temperature, respectively. , and These represent the influence coefficients of the three execution quantities on the evaporation saturation temperature, respectively.

[0040] The temperature and pressure regulation of the liquid reservoir is further converted into the inflation and deflation regulation of the liquid reservoir bladder and the heating power regulation of the liquid reservoir, so that the outlet dryness, inlet thermal state and evaporation saturation state converge synchronously to their respective target values.

[0041] The gas-liquid two-phase circulating working fluid output from the evaporator is sequentially passed through the regenerator and plate condenser for heat release and condensation. The target heat exchange power on the condensing side is determined based on the real-time dryness of the evaporator outlet, the mass flow rate of the circulating working fluid, the condenser outlet temperature, and the target condensation outlet temperature. The refrigeration output of the chiller is adjusted according to the target heat exchange power on the condensing side to keep the circulating working fluid output from the condenser in a preset liquid phase state. The target heat transfer power on the condenser side is: , The condensation state compensation factor is: , The target cooling capacity of the chiller is: , in, This is the condensation pressure; This refers to the evaporator outlet temperature. This refers to the actual outlet temperature of the condenser. The target condenser outlet temperature; The specific heat of the circulating working fluid at constant pressure in the liquid phase; The power coefficient is used to compensate for the condensation state. It is a sensitive scale for the temperature deviation of the condenser outlet; This refers to the refrigeration safety margin factor. and These are the minimum and maximum allowable cooling power of the chiller, respectively.

[0042] Specifically, the outlet dryness, evaporator inlet temperature, and evaporation saturation temperature are used as the basis for coordinated feedback to control the adjustment of the circulating pump, preheater, and liquid receiver in a coordinated manner. This allows the flow rate regulation, inlet temperature regulation, and saturation state regulation to work together to quickly correct the system's operating state when the heat load changes, reduce fluctuations in evaporation temperature and outlet dryness, and thus improve the adaptability of the pump-driven two-phase flow cooling system to changing operating conditions and the overall temperature control stability.

[0043] In summary, this invention constructs a closed-loop control architecture encompassing "collaborative regulation of the saturated state of the liquid receiver—adaptive tuning of the preheater inlet thermal state—active feedback of evaporator outlet dryness—global optimal collaborative decision-making by multiple actuators—dynamic matching response on the condenser side." This method achieves precise control of the gas-liquid two-phase state of the liquid receiver through weighted fusion of multiple temperature measurement points. It dynamically determines the target subcooling degree through the phase change load coefficient to ensure the working fluid at the evaporator inlet is in a stable liquid phase state. In particular, it overcomes the limitations of traditional methods that passively monitor outlet dryness, introducing it as an active feedback variable into the closed loop and coordinating it with the circulating pump speed, preheater power, and liquid receiver temperature and pressure through multi-variable decoupled control. Combined with dynamic heat transfer power matching on the condenser side based on dryness and compensation factors, the system simultaneously suppresses evaporation temperature drift and outlet dryness oscillation under wide heat load fluctuations, avoiding potential hazards such as two-phase flow instability, dry burning, and cavitation. This achieves high-precision, high-stability, and all-condition adaptive thermal management of the cooled object's temperature, providing a reliable and efficient two-phase cooling solution for high-power electronic devices, laser weapons, and aerospace thermal control.

[0044] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A pump-driven two-phase flow cooling control method based on precise temperature control, characterized in that, include: Step 1: Obtain the target evaporation saturation temperature, determine the corresponding target saturation pressure based on the temperature-saturation pressure relationship of the circulating working fluid, and adjust the temperature and pressure of the circulating working fluid in the reservoir in a coordinated manner based on the target saturation pressure so that the circulating working fluid reaches the target gas-liquid two-phase saturation state. Step 2: Based on the target gas-liquid two-phase saturation state formed in Step 1, drive the circulating working fluid to circulate, and adjust the heating power of the preheater according to the target evaporation saturation temperature and the mass flow rate of the circulating working fluid, so that the circulating working fluid entering the evaporator reaches the preset inlet thermal state. Step 3: The circulating working fluid adjusted in Step 2 is delivered to the evaporator to absorb the heat of the object being cooled, and the temperature, pressure and mass flow rate parameters during the operation of the evaporator are collected to obtain the real-time operating status parameters of the circulating working fluid. Step 4: Based on the real-time operating status parameters obtained in Step 3 and the effective heat absorbed by the circulating working fluid, determine the real-time dryness of the circulating working fluid at the evaporator outlet, and determine the dryness deviation of the real-time dryness relative to the target dryness range. Step 5: Based on the dryness deviation determined in Step 4 and the real-time operating status parameters obtained in Step 3, perform coordinated feedback control on the flow rate adjustment, inlet temperature adjustment, and saturation state adjustment of the circulating working fluid to keep the evaporation saturation temperature and evaporator outlet dryness within the corresponding target range.

2. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 1, characterized in that, In step 1, the temperature and pressure of the circulating working fluid in the reservoir are regulated in a coordinated manner, including: collecting the actual temperature corresponding to multiple temperature measuring positions in the reservoir, determining the equivalent temperature of the reservoir based on the deviation of each actual temperature from the median temperature and the historical temperature fluctuation corresponding to each temperature measuring position, and determining the saturation state deviation based on the equivalent temperature of the reservoir, the actual pressure of the reservoir, the target evaporation saturation temperature, and the target saturation pressure.

3. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 2, characterized in that, In step 1, the inflation and deflation adjustment amount of the reservoir bladder is determined based on the pressure deviation between the actual pressure of the reservoir and the target saturation pressure, and the temperature deviation between the equivalent temperature of the reservoir and the target evaporation saturation temperature. The heating power of multiple heating units set at different positions of the reservoir is determined based on the actual temperature corresponding to each temperature measurement position.

4. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 1, characterized in that, The preset inlet thermal state in step 2 is either a saturated liquid phase state or a liquid phase state with a target subcooling. The target subcooling is determined based on the current heat load of the object being cooled, the mass flow rate of the circulating working fluid, and the latent heat of vaporization of the circulating working fluid in the current saturated state, so that the circulating working fluid is fully preheated before entering the evaporator and does not undergo a phase change.

5. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 1, characterized in that, The speed of the circulating pump is nonlinearly iteratively adjusted based on the flow deviation between the real-time mass flow rate of the circulating working fluid and the target mass flow rate, as well as the dryness deviation between the real-time dryness of the evaporator outlet and the target dryness.

6. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 1, characterized in that, In step 3, the evaporator inlet temperature, evaporator outlet temperature, evaporator inlet pressure, evaporator outlet pressure, evaporator inlet-outlet pressure difference, and circulating working fluid mass flow rate are constructed into a real-time operating state vector. The evaporator thermodynamic state deviation index is determined based on the normalized deviation of each operating parameter in the real-time operating state vector relative to the corresponding reference state value. The temperature, pressure, and mass flow rate are collected by thermocouples, pressure sensors, and mass flow meters, respectively.

7. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 6, characterized in that, In step 4, the effective heat absorption power of the circulating working fluid for phase change is determined based on the thermal power input to the evaporator, the pre-calibrated system heat loss, and the inlet specific enthalpy when the circulating working fluid enters the evaporator. The real-time dryness of the evaporator outlet is then determined based on the effective heat absorption power, the mass flow rate of the circulating working fluid, and the thermophysical parameters corresponding to the current evaporation pressure.

8. The pump-driven two-phase flow cooling control method based on precise temperature control according to claim 7, characterized in that, The real-time dryness at the evaporator outlet is compared with the target dryness range defined by the lower and upper limits of the target dryness, and the dryness feedback flow correction amount is determined based on the direction and degree of deviation of the real-time dryness from the target dryness range.

9. A pump-driven two-phase flow cooling control method based on precise temperature control according to claim 8, characterized in that, In step 5, a control error vector is constructed based on the evaporator outlet dryness deviation, evaporator inlet temperature deviation, and evaporation saturation temperature deviation. Based on the sensitivity of the circulating pump, preheater, and liquid receiver to each control error, the circulating pump speed adjustment, preheater heating power adjustment, and liquid receiver temperature and pressure coordinated adjustment are determined. The liquid receiver temperature and pressure coordinated adjustment is further converted into liquid receiver gasbag filling and venting adjustment and liquid receiver heating power adjustment, so that the outlet dryness, inlet thermal state, and evaporation saturation state converge synchronously to their respective target values.

10. A pump-driven two-phase flow cooling control method based on precise temperature control according to claim 9, characterized in that, The gas-liquid two-phase circulating working fluid output from the evaporator is sequentially passed through a regenerator and a plate condenser for heat release and condensation. The target heat exchange power on the condensing side is determined based on the real-time dryness of the evaporator outlet, the mass flow rate of the circulating working fluid, the condenser outlet temperature, and the target condensation outlet temperature. The refrigeration output of the chiller is adjusted according to the target heat exchange power on the condensing side to keep the circulating working fluid output from the condenser in a preset liquid phase state.

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