Jet Device Research Articles

Study on Water Jet Characteristics of Square Nozzle Based on CFD and Particle Image Velocimetry

Water jet technology is widely used in various fields, in which the nozzle is an important element to form the jet. To solve the problem of low water jet operation efficiency of square nozzles, the internal flow channel structure of the nozzle of the key jet device is studied. Through the combination of computational fluid dynamics (CFD) and particle image velocimetry (PIV) experiments, the influence of main structural parameters such as the contraction angle and length-to-diameter ratio of the inner flow channel on the velocity and length of the constant-velocity core region is explored. Since the jet flow structure is a symmetrical structure along the axial direction, the model of the jet flow structure was built half of the model along the axial direction. The results show that a smaller length-to-diameter ratio and a smaller contraction angle of the nozzle result in better jet cohesion and lower dynamic pressure in the constant-velocity core area, which is more suitable for long-distance, low-pressure water jet operations.

Application of an atmospheric pressure plasma jet in a rat model of ischaemic stroke: Design, optimisation, and characteristics

AbstractRecent studies have shown the in vitro neuro‐protective functions of atmospheric pressure plasma (APP) against multiple pathological injuries during ischaemic stroke (IS). However, whether APP treatment exerts a therapeutic effect on a rat IS model remains unclear. Here, on the basis of needle‐to‐ring dielectric barrier discharge, an atmospheric pressure plasma jet (APPJ) was designed, with the Helium as the working gas which was driven by a sinusoidal voltage. Then, the treatment conditions were optimised for IS rat model treatment and the characteristics of this APPJ were further diagnosed. Subsequently, the rat IS model was established through 90 min middle cerebral artery occlusion (MCAO), and plasma was intermittently inhaled by rats via the nasal cavity for a 2 min period at 60 min of MCAO process. The therapeutic effects of this plasma jet device were then evaluated using biomedical analyses. According to our results, intermittent APP inhalation in the MCAO rats increased the serum NO content, improved the neurological function, enhanced regional cerebral blood flow, lowered brain infarction, and reduced the cell apoptosis in brain tissues of MCAO rats. Collectively, our data provides a novel potential strategy for IS treatment by using atmospheric‐pressure plasma inhalation.

Wound healing in db/db mice with type 2 diabetes using non-contact exposure with an argon non-thermal atmospheric pressure plasma jet device.

A non-thermal atmospheric pressure plasma jet (APPJ) may stimulate cells and tissues or result in cell death depending on the intensity of plasma at the target; therefore, we herein investigated the effects of non-thermal plasma under non-contact conditions on the healing of full-thickness wounds in diabetic mice (DM+ group) and normal mice (DM- group). A hydrogen peroxide colorimetric method and high performance liquid chromatography showed that APPJ produced low amounts of reactive oxygen and nitrogen species. Ten-week-old male C57BL/6j mice with normal blood glucose levels (DM- group) and 10-week-old male C57BLKS/J Iar-+Leprdb/+Leprdb mice (DM+ group) received two full-thickness cutaneous wounds (4 mm in diameter) on both sides of the dorsum. Wounds were treated with or without the plasma jet or argon gas for 1 minute and were then covered with a hydrocolloid dressing (Hydrocolloid), according to which mice were divided into the following groups: DM+Plasma, DM+Argon, DM+Hydrocolloid, DM-Plasma, DM-Argon, and DM-Hydrocolloid. Exudate weights, wound areas, and wound area ratios were recorded every day. Hematoxylin and eosin staining was performed to assess re-epithelialization and α-SMA immunohistological staining to evaluate the formation of new blood vessels. Non-thermal plasma under non-contact conditions reduced the production of exudate. Exudate weights were smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups. The wound area ratio was smaller for plasma-treated wounds, and was also smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups on days 1–21 (p<0.01). Wound areas were smaller in the DM-Plasma group than in the DM-Argon group until day 14 and differences were significant on days 1–5 (p<0.01). The percentage of re-epithelialization was significantly higher in the DM+Plasma group than in the DM+Argon and DM+Hydrocolloid groups (p<0.01). The number of new blood vessels that had formed by day 7 was significantly higher in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups (p<0.05). These results indicate that treatment with the current non-thermal plasma APPJ device under non-contact conditions accelerated wound healing in diabetic mice.

Enhance the inactivation of fungi by the sequential use of cold atmospheric plasma and plasma-activated water: Synergistic effect and mechanism study

Cold atmospheric plasma (CAP) has been widely applied for microbe inactivation. Previous studies revealed that the inactivation efficiency could be improved with the sequential use of plasma-activated water (PAW) after the direct CAP treatment, while the mechanism requires further exploration. In this work, we employed a CAP jet device and investigated the inactivation effect of CAP combined with PAW treatment on two kinds of fungi (Saccharomyces cerevisiae and Aspergillus flavus), and particularly, we examined the synergistic effect by scrutinizing the roles of varied reactive species. Our experimental results showed that short-term CAP treatment combined with the continued long-term (e.g., 120 min) PAW treatment led to significant reduction of Saccharomyces cerevisiae/Aspergillus flavus, with the disinfection effect equivalentto the single CAP approach with much longer treatment time. The comparative analysis revealed that the inactivation of fungi was induced by different reactive oxygen and nitrogen species (RONS) during the combination of CAP and PAW treatments, which had different influences on the fungal morphology, membrane permeability, intracellular RONS and energy metabolism. In the first stage of CAP treatment, the plasma produced ·OH and 1O2, could directly destroy the structure of fungal wall and membrane, leading to cell death. While in the subsequent PAW treatment, the reactive nitrogen species (RNS) could enter cell and influence metabolic activities, leading inactivation of more fungi. The synergistic effect was attributed to the increasing of intracellular 1O2 and ONOO– induced membrane damage, causing the irreparable oxidative damage to mitochondria and energy metabolic system. This mechanistic study may thus provide a new guidance for the optimal application of low-temperature plasma technology in the application of fungal disinfection with high efficiency.

Atmospheric plasma jet for surface treatment of biomaterials

A direct current (DC) powered low-temperature atmospheric pressure plasma (LTAPP) jet device was built and used to sterilize Escherichia coli (E. coli) bacteria. The plasma jet’s general properties, such as length and temperature, were first tested and found to be strongly related to the plasma jet’s operational flow mode (laminar or turbulent flow). The optical emission spectra of various gas mixtures were measured to confirm the presence of active radicals, which is critical for sterilization success. Pure helium gas or a combination of helium with a small percentage of oxygen (6.25%) was found to have the highest intensities of bactericidal species such as atomic oxygen (O) and hydroxide (OH). These mixtures were then used to treat E. coli bacteria previously grown in a Petri dish. Sterilization was accomplished by repeatedly treating the bacteria for 10 s for 5–10 rounds for short periods. The best results were obtained when the bacteria had enough time to rest between rounds.

An innovative idea: Injection valves for irrigation ducts

More than 4.6 mln ha in the Russian Federation are irrigated. Their culvert hydraulic structures are part of network structures and are the most widespread. After the crisis of the 1990s, proper maintenance of many reclamation systems was impossible due to a lack of funds. This led to the loss of about half of the water taken from irrigation sources in irrigation canals. The planned increase in the technical level of irrigation systems requires the automation of the operation of both the entire system as a whole and separately located culverts. This will avoid significant losses of water supply for irrigation and prevent water shortages with the insufficient discipline of water users. Means of hydraulic automation of water supply are being installed on small irrigation canals in Russia. A water flow regulating valve is proposed, with no mechanical movinparts, and gates are not involved in the control process. The operation of the structure is based on the injection effect, in which excess water entering the downstream with a decrease in water consumption begins to circulate between the outlet section of the transit pipe and the diffuser at the end section of the valve. Using the methods of measuring hydrodynamics and the theory of jet devices, theoretical dependences were obtained, which make it possible to determine the main hydraulic characteristics of the structure. The design form of the flow part of the regulator has been developed and a physical model has been made. In a mirror hydraulic flume, the operation modes of the water outlet were studied with and without regulation. The actual values of hydraulic parameters were obtained, which confirmed the validity of the use of theoretical dependencies. The discrepancy between the theoretical and experimental results is within the experimental error. It has been proven that it is possible to circulate excess water between the downstream and intermediate pools of the regulator.

Open Questions in Cold Atmospheric Plasma Treatment in Head and Neck Cancer: A Systematic Review.

Over the past decade, we witnessed a promising application of cold atmospheric plasma (CAP) in cancer therapy. The aim of this systematic review was to provide an exhaustive state of the art of CAP employed for the treatment of head and neck cancer (HNC), a tumor whose late diagnosis, local recurrence, distant metastases, and treatment failure are the main causes of patients’ death. Specifically, the characteristics and settings of the CAP devices and the in vitro and in vivo treatment protocols were summarized to meet the urgent need for standardization. Its molecular mechanisms of action, as well as the successes and pitfalls of current CAP applications in HNC, were discussed. Finally, the interesting emerging preclinical hypotheses that warrant further clinical investigation have risen. A total of 24 studies were included. Most studies used a plasma jet device (54.2%). Argon resulted as the mostly employed working gas (33.32%). Direct and indirect plasma application was reported in 87.5% and 20.8% of studies, respectively. In vitro investigations were 79.17%, most of them concerned with direct treatment (78.94%). Only eight (33.32%) in vivo studies were found; three were conducted in mice, and five on human beings. CAP showed pro-apoptotic effects more efficiently in tumor cells than in normal cells by altering redox balance in a way that oxidative distress leads to cell death. In preclinical studies, it exhibited efficacy and tolerability. Results from this systematic review pointed out the current limitations of translational application of CAP in the urge of standardization of the current protocols while highlighting promising effects as supporting treatment in HNC.

Study of unique aspects of oxidative-nitrosative environment in a radio frequency cold plasma device

The study reports unique aspects of oxidative and nitrosative environment and generation of radicals in a newly developed 13.56 MHz cold atmospheric pressure plasma jet (APPJ) device using optical emission spectroscopy (OES). Signature of generated species, species density, energy, their spatial variation and interaction with liquid medium are investigated. While techniques to achieve controlled generation of atomic oxygen and nitrogen in the same device are identified, distinct ability of pure argon APPJ to break oxygen molecules in air releasing atomic oxygen is an interesting finding. Boltzmann plot technique is used to determine the electron excitation temperature. Time averaged gas temperature is measured using mercury thermometer as well as matching simulated and experimental spectra of A-X band of OH radical. Electron density is determined from spectral broadening of Hα line. Formation of OH radical is detected via its signature A-X band. Measured electron density and electron excitation temperature are of the order of 1021 per m3, and 3 eV respectively at the nozzle exit. Standard test strips are used to investigate generation of H2O2, NO2 and NO3 radicals through interaction of the plasma jet with water as a function of time.

Vortex-induced vibration of flexible riser transporting high-speed spiral flow in deep-sea mining

According to Hamilton's principle and a mechanical decomposition model proposed for high-speed spiral flow, vibration governing equations of flexible riser transporting high-speed spiral flow are developed for vortex-induced vibration (VIV) analysis for lifting pipe system in deep-sea mining. The classic van der Pol oscillator is used to simulate the dynamic characteristics of VIV. The governing equations are then discretized and solved by the finite element method and the Runge-Kuta method. Furthermore, dynamic characteristics of VIV of the flexible riser transporting straight flow and spiral flow are investigated and the effects of the spiral flow incidence velocity and angle controlled by the jet device on VIV responses are evaluated. Also, the VIV dynamics considering different damping ratios are examined. The results show that the rotational angular velocity of the spiral flow would amplify the mean deflection of the in-line (IL) direction, and the incidence velocity has a significant nonlinear effect on the dominant frequency of the riser, which would induce the high-order dominant vibration modes when the incidence velocity is large sufficiently. However, the incidence angle has relatively less effects on the VIV responses of flexible riser. Moreover, the locked interval of VIV is less influenced by damping ratio below 0.1.

Breath-dependent pressure fluctuations in various constant- and variable-flow neonatal CPAP devices.

In continuous positive airway pressure(CPAP) devices, pressure can be generated by two different mechanisms: either via an expiratory valve or by one or more jets. Valved CPAP devices are referred to as constant-flow devices, and jet devices are called variable-flow devices. Constant-flow CPAP devices are said to reduce the imposed work of breathing due to lower breath-dependent pressure fluctuations. The present study investigates the performance of various constant-and variable-flow CPAP devices in relation to breath-dependent pressure fluctuations. Experimental study comparing the pressure fluctuations incurred by seven neonatal CPAP devices attached to an active neonatal lung model. Spontaneous breathing was simulated using a tidal volume of 6 ml at pressure levels of 5, 7, and 9 mbar. The main outcomes were respiratory pressure fluctuations, tidal volume, and end-expiratory pressure. All CPAP devices tested showed respiratory pressure fluctuations, varying from 0.631to 3.466 mbar. The generated tidal volume correlated significantly with the pressure fluctuations (r = -0.947; p = 0.001) and varied between 5.550and 6.316 ml. CPAP devices with jets showed no advantage over CPAP devices with expiratory valves. End-expiratory pressure in the nose deviated from the set pressure between -1.305and 0.644 mbar and varied depending on whether the pressure was measured in the device or in the tube extending to the nose. During standard spontaneous breathing, breath-dependent pressure fluctuations in constant-and variable-flow devices are comparable. Pressure measurements taken in the tubing system can lead to a considerable deviation of the applied pressure.

Ion temperature spectroscopic measurements in high rotation discharges by means of X-ray diagnostic at JET

Measurement of the X-ray spectra of the He-like Ni ions (Ni26+) and their dielectronic satellites (Ni25+, Ni24+, and Ni23+) plays a crucial role in determination of electronic and ion temperature of plasma in the JET device. Because n ⩾ 3 satellites of Ni25+ overlap with resonance line of Ni26+, it is important to reconstruct the structure of these satellites reliably. It is especially important in the cases when plasma rotation is high which may result in an additional broadening of the resonance line. This work is an attempt to identify possible causes of the additional broadening of the resonance line due to the effect of overlapping the dielectronic satellites with the resonance line of Ni26+ and the effect of toroidal plasma rotation shear.

Development of oil well development technology using jet pumps after hydraulic fracturing

For the development of production wells with degraded filtration parameters in domestic and foreign practice, various methods are used. But, as the practice of work has shown, the most effective means of development and research of production wells are jet devices, which are distinguished by their simplicity of design and the possibility of their use in various mining and geological conditions. The article proposes technology and technical means to improve the connection between the well and the reservoir, increase the coverage of the fractured space, reduce material and time costs during well development. It is shown that complex technological solutions during development after hydraulic fracturing lead to an increase in the production rate of oil wells.

Well surveys with jet pumps after hydraulic fracturing

Hydraulic fracturing (HF) is successfully used all over the world and allows to increase the efficiency of the well, as well as to put into operation wells with plugged bottomhole zone. Service companies every year pay more and more attention to hydraulic fracturing and the promotion of new solutions to further increase the efficiency of this technology, which contributes to its importance in the stimulation of production. The main advantage of hydraulic fracturing is to increase the drainage area of the reservoir, and especially when performing multi-stage hydraulic fracturing (MSHF). Violation of the induction stimulation technology after hydraulic fracturing can lead to proppant blowback not only at the development stage, but also at the well operation stage. One of the solutions to prevent such complications is the use of jet devices, which make it possible to fix the proppant in the fracture and reduce the well development period. The article investigates the results of hydrodynamic studies of wells with jet pumps. Various forms of indicator diagrams are given and their description is made. The method of calculation of reservoir parameters by pressure build-up has been studied. The results of data processing of hydrodynamic studies by a jet pump are presented.

30-LB: Multicenter, Randomized Controlled Clinical Investigation Evaluating a Unique Micro Water Jet Technology Device Versus Standard Debridement in the Treatment of Diabetic Foot

Background: Proper debridement of the wound base is critical to facilitate wound granulation and closure in non-healing diabetic foot ulcers (DFUs) . A unique micro water jet device has been developed that precisely cleans acute and chronic wounds in a tissue-preserving manner while performing a precise mechanical cleaning and stimulation of the wound base to enhance granulation and healing. In this trial the device was used to treat non healing DFUs. Methods: 85 patients were screened, and 50 patients were enrolled for the preliminary analysis, in a two arm randomized controlled trial. Diabetic foot wounds that were non-healing for at least 4 weeks, with adequate blood flow and were void of clinical infection or osteomyelitis were entered into 2 weeks of screening. Those that met all the qualifications were randomized to receive either weekly micro jet wound debridement or standard sharp debridement along with SOC wound dressing and offloading. Both groups were followed for 16 weeks. The study endpoints included healing at 16 weeks as well as percent area wound reduction (PAR) over the treatment phase of 16 weeks. Results: At 16 weeks 72% (18/25) of the Micro Water jet treated DFUs healed compared with 40% (10/25) treated with standard sharp debridement p=0.023 (unadjusted) . Furthermore, at 16 weeks, the percent area reduction (PAR) was 86.5% (SD: 25.60) for the wounds treated with the Micro Water Jet versus 35.1% (SD: 164.47) with standard sharp wound debridement p=0.021 (unadjusted) . The safety analysis showed with regard to wound related adverse events (AE) and serious adverse events (SAE) ; 1 AE and 1 SAE occurring in the Micro Water jet group versus 9 AEs and 4 SAEs in the standard sharp debridement group. Conclusion: The micro water jet device was able to statistically significantly close more refractory DFUs over 16 weeks, with a significant difference in wound area reduction that should be noted. Further evaluation with larger randomized controlled trials are warranted to validate these initial promising findings. Disclosure D. G. Armstrong: None. C. Zelen: Research Support; Geistlich Pharma, Medaxis LLC, Musculoskeletal Transplant Foundation, PolarityTE, Inc. Funding Medaxis LLC (A0010)

Efficiency of biofilm removal by combination of water jet and cold plasma: an in-vitro study.

BackgroundPeri-implantitis therapy is a major problem in implantology. Because of challenging rough implant surface and implant geometry, microorganisms can hide and survive in implant microstructures and impede debridement. We developed a new water jet (WJ) device and a new cold atmospheric pressure plasma (CAP) device to overcome these problems and investigated aspects of efficacy in vitro and safety with the aim to create the prerequisites for a clinical pilot study with these medical devices.MethodsWe compared the efficiency of a single treatment with a WJ or curette and cotton swab (CC) without or with adjunctive use of CAP (WJ + CAP, CC + CAP) to remove biofilm in vitro from rough titanium discs. Treatment efficacy was evaluated by measuring turbidity up to 72 h for bacterial re-growth or spreading of osteoblast-like cells (MG-63) after 5 days with scanning electron microscopy. With respect to application safety, the WJ and CAP instruments were examined according to basic regulations for medical devices.ResultsAfter 96 h of incubation all WJ and CC treated disks were turbid but 67% of WJ + CAP and 46% CC + CAP treated specimens were still clear. The increase in turbidity after WJ treatment was delayed by about 20 h compared to CC treatment. In combination with CAP the cell coverage significantly increased to 82% (WJ + CAP) or 72% (CC + CAP), compared to single treatment 11% (WJ) or 10% (CC).ConclusionThe newly developed water jet device effectively removes biofilm from rough titanium surfaces in vitro and, in combination with the new CAP device, biologically acceptable surfaces allow osteoblasts to grow. WJ in combination with CAP leads to cleaner surfaces than the usage of curette and cotton swabs with or without subsequent plasma treatment. Our next step will be a clinical pilot study with these new devices to assess the clinical healing process.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12903-022-02195-1.

A novel designed 3D multi-microhole plasma jet device driven by nanosecond pulse at atmospheric pressure

A novel designed three-dimensional (3D) multi-microhole helium plasma jet device excited by nanosecond pulse is developed in atmospheric air. Systematical investigations about the discharge characteristics are carried out to get insights into the formation mechanisms of 3D plasma jets. Results show that the 3D plasma jets originated from the branching of a single ionization wave to present a hexagonal-like structure including bottom jet (BJ) and side jets (SJ1 and SJ2). The BJ always keeps a stable performance while the SJ displays a remarkably turbulent mode. The dynamic evolution, and the propagation velocity and distance for BJ and SJ demonstrate significant differences, with a delay effect between BJ and SJ bullets propagation being observed. The optical emission spectra show that 3D jets possess a high yield of the spatial distribution of reactive species in jet plumes. The formation mechanism of 3D jets is determined by the hydrodynamic (He flow distribution) and electrical interactions (distribution of electric field force) in the discharge tube emerging from individual holes with different radial directions. The direct treatment of water using this developed underwater 3D plasma device results in the production of plasma activated water with a lower pH value, higher conductivity, and greater concentrations of reactive oxygen and nitrogen species, compared to the indirect treatment. Especially, the concentration of H2O2 can remarkably increase 141 folds from 1.43 to 202.12 μM within 5 min after the direct 3D plasma treatment. This novel-designed 3D jets-based technique is a promising platform for 3D application scenarios, especially in the case of underwater microbubble discharge, which is of great significance for water activation in emerging applications.

Experimental and Numerical Investigations of Modified Synthetic Jet Actuator for Active Flow Control

This paper presents the results of experimental and numerical investigations on synthetic jet actuators with various arrangements. First, an actuator with one membrane in the cavity is a standard, reference arrangement; and second, one novel modified arrangement has two membranes in the cavity. Authors use constant temperature-anemometry measurements to identify the characteristic frequencies in which the output jet velocity reaches a maximal value, namely, the resonant frequency of the actuator (Helmholtz frequency) and of the membrane (structural resonance). A numerical model of a synthetic jet actuator has been validated using experimental data for the case with one membrane in a cavity. The simulation results confirm the existence of a toroidal vortex at the actuator exit for the frequencies determined in the experiment. Numerical results of a modified actuator with two membranes in the cavity give promising results in the context of separation control by synthetic jet devices, i.e., increase of output velocity and vorticity from the same occupied space is obtained. Numerical simulations show that in the modified actuator with two membranes in the cavity, the jet output velocity and vorticity of a created toroidal vortex at the actuator outlet can be increased by 80%, compared to the case with one membrane. The new geometry of a synthetic jet actuator with perpendicular membranes is to be implemented into the wind tunnel measurements to prove the use of a modified synthetic jet actuator as a device applicable for active flow control.

Realizing high efficiency and large-area sterilization by a rotating plasma jet device

By tilting a plasma jet and rotating 360°, a large-area can be scanned and sterilized in a short time. Compared with the previous array device, this pipe has the significant advantages of high sterilization uniformity and low gas consumption. Firstly, a rotatable plasma jet device, which can control the swing and rotation of a jet pipe, is designed, and a corresponding theoretical model is established to guide the experiment. Secondly, with Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as the target bacteria, the device achieves a short sterilization time of 158 s—the minimum sterilization flow of S. aureus and E. coli is 0.8 slm and 0.6 slm, respectively. The device is compared with an array plasma sterilization device in terms of sterilization speed and gas consumption. The results show that the device is not only better than an array plasma sterilization device with respect to scanning uniformity, but also far less than the array plasma sterilization device in gas consumption of 5 slm. Therefore, the device has great potential in applications involving efficient, large-area sterilization.

An in‐depth review of novel cold plasma technology for fresh‐cut produce

Fresh-cut fruits and vegetables refer to edible commodities that are free from large-scale and typical traditional processing operations. However, maintaining their nutritional value and microbiological integrity is challenging. The processing operations such as peeling, cutting, and trimming done in the fresh-cut industry can trigger deteriorative reactions such as tissue softening and enzymatic browning. As a countermeasure, cold plasma technology has emerged as an innovation for minimal processing of several edible foods including fresh-cut produce. Cold plasma may be generated using a variety of technologies, including microwave frequencies, infrared frequencies, radio-wave frequencies, dielectric barrier discharge, and plasma jet devices. This review enlightens the effects of cold plasma on fresh-cut produce from physicochemical and organoleptic aspects. Although cold plasma technology has proven to be beneficial for fresh-cut fruits and vegetables, several aspects, including its impact on nutrition and flavor, need to be investigated further. Novelty impact statement Cold plasma, being one of the most advanced and safest of techniques, has been extensively discussed with reference to different types, techniques, and operational parameters used in various studies. This review highlights non-thermal novelties in the processing and preservation of fresh-cut produce. The effects of cold plasma technology on the physicochemical attributes, organoleptic characteristics, and shelf life of fresh-cut fruits and vegetables have been reviewed.

Closed cooling systems of ship power plants with heat sleeve through ship's cladding

The drawbacks of widespread open-loop cooling systems for ship power plants are analyzed. It is shown that as a result, the seas are caused significant ecological damage. The operation of such systems in a polluted water area can lead to clogging of the system and its emergency shutdown. The issue of various options for creating closed cooling systems with heat removal through the ship's skin is considered. This eliminates the need to receive seawater. Experimental data for labyrinth and jet type devices are presented. Moreover, the latter are distinguished by a greater simplicity of design. Generalizing similarity equations describing the ongoing processes are determined. The achieved heat transfer coefficients on the inner surface of the ship's hull plating are compared. It has been determined that jet devices are characterized by better performance compared to labyrinth ones. The difference becomes most noticeable when the vessel is moving, compared to the case of anchorage. This allows us to recommend jet devices for wider implementation in shipbuilding practice.