Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling最新文献_第2页

Cooling Performance of Additively Manufactured Pin Fins in Stacked Microchannels for the Inside-Out Ceramic Turbine Shroud-Cooling Ring 外置式陶瓷涡轮罩冷却环叠合微通道增材制造销翅冷却性能研究

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-60100

P. K. Dubois, A. Landry-Blais, R. Gazzah, S. Šivić, V. Brailovski, M. Picard

{"title":"Cooling Performance of Additively Manufactured Pin Fins in Stacked Microchannels for the Inside-Out Ceramic Turbine Shroud-Cooling Ring","authors":"P. K. Dubois, A. Landry-Blais, R. Gazzah, S. Šivić, V. Brailovski, M. Picard","doi":"10.1115/gt2021-60100","DOIUrl":"https://doi.org/10.1115/gt2021-60100","url":null,"abstract":"\u0000 The Inside-out ceramic turbine (ICT), a novel microturbine rotor architecture, has an air-cooled ring which keeps its composite rotating structural shroud within operating temperature. The cooling ring must achieve a significant radial temperature gradient with a minimal amount of cooling. The cooling ring is made through additive manufacturing, which opens the design space to tailored cooling geometries. Additively manufactured pin fin heat transfer enhancers are explored in this work to assess whether they hold any significant performance benefit over current rectangular cross-section open channels. Experimental friction factors and Nusselt numbers were determined for small, densely-packed pin fins over an asymmetrical thermal load.\u0000 Results indicate that pressure loss is similar to what can be expected for additively manufactured pin fins, whereas heat transfer is lower due to the extremely tight streamwise pin spacing, in both in-line and staggered pin configurations. A design study presented in this paper suggests that pin fins are beneficial to an ICT for reducing cooling mass flow rate up to 40%, against an increase in cooling ring mass of roughly 50%.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134465482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

On the Extrapolation of Rim Sealing Performance From Test Bench to Real Engine: A Numerical Survey 从试验台到实际发动机轮辋密封性能的外推:数值调查

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59076

R. D. Soghe, C. Bianchini, L. Mazzei, A. Bonini, L. Innocenti, D. D. Benedetto, Lorenzo Orsini

{"title":"On the Extrapolation of Rim Sealing Performance From Test Bench to Real Engine: A Numerical Survey","authors":"R. D. Soghe, C. Bianchini, L. Mazzei, A. Bonini, L. Innocenti, D. D. Benedetto, Lorenzo Orsini","doi":"10.1115/gt2021-59076","DOIUrl":"https://doi.org/10.1115/gt2021-59076","url":null,"abstract":"\u0000 The main annulus hot gas ingress into turbine wheel-spaces is still one of the most challenging problem designers face. During the decades, several experimental test benches were developed worldwide to improve the knowledge associated to the rim seal flow physics. Even if in some cases quite complex and advanced rig configurations were proposed, limitations in the operating conditions and in the reproduction of the real engine geometries/characteristics into the rig are present.\u0000 In this paper, validated CFD computations are used to explore the impact of some experimental rigs design choices/limitations on the sealing effectiveness prediction and their ability to mimic the real engine configuration behaviour. Attention is paid on several test rig related aspects such as operating conditions, flow path configuration (blade and vane count) and accuracy in the real engine rim seal geometry reconstruction applied to the rig.\u0000 From the computations it emerges that a scaled geometry operated at lab conditions is able to mimic pretty well the real engine sealing performance when rig and engine experience the same flow path ΔCp. The ability of the rig to match the engine data is not affected by the differences in main annulus Mach number between test bench and engine.\u0000 A further result that emerges from the computation regards the fact that the Φ0 - ΔCp0.5 curve is not linear, proving that the linear extrapolation of rim sealing performance from test bench to real engine when rig and engine are characterized by different ΔCp0.5 values is not of general application and an alternative approach is given.\u0000 Finally, it is found that the impact of vane count on the rim sealing effectiveness is significant, making the extrapolation of data from rig to engine difficult.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115060516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Impact of Ceramic Matrix Composite Topology on Friction Factor and Heat Transfer 陶瓷基复合材料拓扑结构对摩擦系数和传热的影响

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59588

Trevor M. Cory, Ryan D. Edelson, K. Thole, T. Vincent, San Quach, Dominic Mongillo

{"title":"Impact of Ceramic Matrix Composite Topology on Friction Factor and Heat Transfer","authors":"Trevor M. Cory, Ryan D. Edelson, K. Thole, T. Vincent, San Quach, Dominic Mongillo","doi":"10.1115/gt2021-59588","DOIUrl":"https://doi.org/10.1115/gt2021-59588","url":null,"abstract":"\u0000 Ceramic matrix composites (CMCs) are of interest for hot section components of gas turbine engines due to their low weight and favorable thermal properties. To implement this advanced composite in a gas turbine engine, characterizing the influence of CMC’s surface topology on heat transfer and cooling performance is critical. However, very few published studies have reported the flow and heat transfer effects caused by this unique surface topology. This study is an experimental and computational investigation to evaluate the effect of weave orientations, relevant to CMC surfaces, on the resulting pressure loss and convective heat transfer within an internal channel. The weave pattern was additively manufactured as the walls of a scaled-up coupon containing a single channel. For each of the three weave orientations, bulk pressure losses and convective heat transfer coefficients were measured over a range of Reynolds numbers.\u0000 Scaling the pressure losses in terms of a friction factor and convective heat transfer coefficients in terms of a Nusselt number showed the importance of choosing the appropriate definition of the hydraulic diameter, which was particularly important for the friction factor. A coupon having one wall with the weave surface increased pressure loss and heat transfer compared to a smooth wall with the largest increases occurring when the CMC weave strands were perpendicular to the flow. Friction factor augmentations were much higher than heat transfer augmentations. When adding the weave to a second channel wall, pressure loss and heat transfer were further increased. Orienting the CMC strands perpendicular to the flow consistently showed the largest augmentations in heat transfer over a smooth channel, but at a much higher pressure loss penalty than that seen with the CMC strands parallel to the flow.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129921770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Calibration of a CFD Methodology for the Simulation of Roughness Effects on Friction and Heat Transfer in Additive Manufactured Components 用于模拟增材制造部件中粗糙度对摩擦和传热影响的CFD方法校准

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59603

L. Mazzei, R. D. Soghe, C. Bianchini

{"title":"Calibration of a CFD Methodology for the Simulation of Roughness Effects on Friction and Heat Transfer in Additive Manufactured Components","authors":"L. Mazzei, R. D. Soghe, C. Bianchini","doi":"10.1115/gt2021-59603","DOIUrl":"https://doi.org/10.1115/gt2021-59603","url":null,"abstract":"\u0000 It is well-known from the literature that surface roughness significantly affects friction and heat transfer. This is even more evident for additive manufactured (AM) components, which are taking an increasingly important role in the gas turbine field. However, the exploitation of numerical approaches to improve their design is hindered by the lack of dedicated correlations and CFD models developed for such high roughness conditions.\u0000 Usually the additive manufactured components are simulated considering the surfaces as smooth or applying an equivalent sand-grain roughness (ks) that results in a velocity shift in the boundary layer. However, determining a priori the most appropriate value of ks is challenging, as dozens of correlations are available, returning scattered and uncertain results. A previous work proved how the CFD prediction of friction and heat transfer returns significant deviations, even exploiting the ks values obtained from experimental tests on the very same test case.\u0000 That work also allowed identification of a promising CFD methodology based on friction and thermal corrections proposed by Aupoix from ONERA. The aim of this work is to further the assessment and calibration activity of the model, by analyzing additional experimental data of friction factor and Nusselt number from new test cases considering different geometries and flow conditions. The new coupons consisted of straight circular channels and wavy channels. This work represents a further step in the generation of a more validated and general methodology for the high-fidelity CFD analysis of additive-manufactured components.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121438120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Effect of Rotation on Heat Transfer in AR = 2:1 and AR = 4:1 Channels Connected by a Series of Crossover Jets 一系列交叉射流连接的AR = 2:1和AR = 4:1通道中旋转对换热的影响

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59426

Srivatsan Madhavan, Prashant Singh, S. Ekkad

{"title":"Effect of Rotation on Heat Transfer in AR = 2:1 and AR = 4:1 Channels Connected by a Series of Crossover Jets","authors":"Srivatsan Madhavan, Prashant Singh, S. Ekkad","doi":"10.1115/gt2021-59426","DOIUrl":"https://doi.org/10.1115/gt2021-59426","url":null,"abstract":"\u0000 Detailed heat transfer measurements using transient liquid crystal thermography were performed on a novel cooling design covering the mid-chord and trailing edge region of a typical gas turbine blade under stationary and rotating conditions. The test section comprised of two channels with aspect ratio (AR) of 2:1 (mid-chord) and 4:1 (trailing edge), where the coolant was fed into the AR = 2:1 channel from the root. Rib turbulators with a pitch-to-rib height ratio (p/e) of 10 and rib height-to-channel hydraulic diameter ratio (e/Dh) of 0.075 were placed in the AR = 2:1 channel at an angle of 60° relative to the direction of flow. The coolant after entering this section was routed to the AR = 4:1 section through a set of crossover jets. The purpose of the crossover jets was to induce sideways impingement onto the pin fins that were placed in the 4:1 section to enhance heat transfer. The 4:1 section had a realistic trapezoidal shape that mimics the trailing edge of an actual gas turbine blade. The pin fins were arranged in a staggered array with a center-to-center spacing of 2.5 times the pin diameter in both spanwise and streamwise directions. The trailing edge section consisted of both radial and cutback exit holes for flow exit. Experiments were performed for a Reynolds number (ReDh(AR = 2:1)) of 20,000 at Rotation numbers (RoDh(AR = 2:1)) of 0, 0.1 and 0.14. The channel averaged heat transfer coefficient on trailing side was ∼28% (AR = 2:1) and ∼7.6% (AR = 4:1) higher than the leading side for Rotation number (Ro) of 0.1. It is shown that the combination of crossover jets and pin-fins can be an effective method for cooling wedge shaped trailing edge channels over axial cooling flow designs.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128833032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Correlating Cavity Sealing Effectiveness to Time-Resolved Rim Seal Events in the Presence of Vane Trailing Edge Flow 在叶片后缘流动存在的情况下，空腔密封效果与时间分辨边缘密封事件的关联

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59285

Shawn Siroka, Iván Monge-Concepción, Reid A. Berdanier, M. Barringer, K. Thole, Christopher W. Robak

{"title":"Correlating Cavity Sealing Effectiveness to Time-Resolved Rim Seal Events in the Presence of Vane Trailing Edge Flow","authors":"Shawn Siroka, Iván Monge-Concepción, Reid A. Berdanier, M. Barringer, K. Thole, Christopher W. Robak","doi":"10.1115/gt2021-59285","DOIUrl":"https://doi.org/10.1115/gt2021-59285","url":null,"abstract":"\u0000 The cavity region between the rotor and stator relies on hardware seals and purge flow to discourage hot gas path air from being ingested into the unprotected wheel space. However, ingestion can occur due to a combination of disk pumping, periodic vane-blade interactions, and three-dimensional seal geometry effects. These mechanisms create flow instabilities that are detrimental to cavity seal performance under certain conditions. In this paper, a one-stage turbine operating at engine representative conditions was utilized to study the effect of steady and time-resolved under-platform cavity temperatures and pressures across a range of coolant flow rates in the presence of vane trailing edge (VTE) flow. This study correlates time-resolved pressure with time-resolved temperature to identify primary frequencies driving ingestion. At certain flow rates, the time-resolved pressures are out of phase with the temperatures, indicating ingestion. These same flow rates were found to correlate to an inflection region in the cooling effectiveness curve where the maximum amplitude of the time-varying behavior coincides with the cooling effectiveness inflection point. Using a time-accurate computational model, simulations near this inflection region illustrate ingestion of high-swirl VTE flow into the cavity region which creates a buffer in the rim seal between swirled main gas path flow and axially injected purge coolant helping to suppress the amplitude of time-resolved behavior.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115318655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Surface Heater Fabrication Using Micro-Lithography for Transpiration Cooling Heat Transfer Coefficient Measurements 用微光刻技术制造表面加热器用于蒸腾冷却传热系数的测量

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59275

Zheng Min, S. Parbat, Qing-Ming Wang, M. Chyu

{"title":"Surface Heater Fabrication Using Micro-Lithography for Transpiration Cooling Heat Transfer Coefficient Measurements","authors":"Zheng Min, S. Parbat, Qing-Ming Wang, M. Chyu","doi":"10.1115/gt2021-59275","DOIUrl":"https://doi.org/10.1115/gt2021-59275","url":null,"abstract":"\u0000 Transpiration cooling is able to provide more uniform coolant coverage than film cooling to effectively protect the component surface from contacting the hot gas. Due to numerous coolant ejection outlets within a small area at the target surface, the experimental thermo-fluid investigation on transpiration cooing becomes a significant challenge. Two classic methods to investigate film cooling, the steady-state foil heater method and the transient thermography technique, both fail for transpiration cooling because the foil heater would block numerous coolant outlets, and the semi-infinite solid conduction model no longer holds for porous plates. In this study, a micro-lithography method to fabricate a silver coil pattern on top of the additively manufactured polymer porous media as the surface heater was proposed. The circuit was deliberately designed to cover the solid surface in a combination of series connection and parallel connection to ensure the power in each unit cell area at the target surface was identical. With uniform heat flux generation, the steady-state tests were conducted to obtain distributions of a pair of parameters, adiabatic cooling effectiveness, and heat transfer coefficient (HTC). The results showed that the adiabatic cooling effectiveness could reach 0.65 with a blowing ratio lower than 0.5. Meanwhile, the heat transfer coefficient ratio (hf/h0) of transpiration cooling was close to 1 with a small blowing ratio at 0.125. A higher HTC ratio was observed for smaller pitch-to-diameter cases due to more turbulence intensity generated at the target surface.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125934621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental Determination of Heat Transfer Coefficient on Impingement Cooled Gear Flanks: Validation of the Evaluation Method 碰撞冷却齿轮侧翼传热系数的实验测定:评估方法的验证

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-58838

E. Ayan, Felix C. von Plehwe, M. Keller, Christian Kromer, C. Schwitzke, H. Bauer

{"title":"Experimental Determination of Heat Transfer Coefficient on Impingement Cooled Gear Flanks: Validation of the Evaluation Method","authors":"E. Ayan, Felix C. von Plehwe, M. Keller, Christian Kromer, C. Schwitzke, H. Bauer","doi":"10.1115/gt2021-58838","DOIUrl":"https://doi.org/10.1115/gt2021-58838","url":null,"abstract":"\u0000 Understanding the heat transfer characteristics of impingement cooling of high-speed high-power gears is essential to design a reliable gearbox for a new generation of jet engines. However, experimental data on the impingement cooling of gears is limited in the literature. The experimental setup at the Institute of Thermal Turbomachinery aims at closing this gap. It includes a rotating gear instrumented with thermocouples. The measured temperatures are used to determine a spatially resolved heat transfer coefficient distribution on the gear tooth. The iterative evaluation approach applied in the post-processing of the experimental data is validated with two reference cases. First, it is shown that the interpolation of temperature data between thermocouple locations leads to inaccurate results and would not be valid for the evaluation of the experiments, even if the number of thermocouples were increased. The iterative evaluation approach can reproduce the reference heat transfer coefficient distributions very accurately even with a low spatial resolution of temperature data. A new iterative method based on the Levenberg-Marquardt algorithm is implemented within this study. The new method generally converges faster than the existing method. The difference in required computational time is negligible in the easy to evaluate high heat transfer case, whereas a speed-up of up to three times is observed in the relatively cumbersome evaluation of the low heat transfer case.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"266 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123492666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Unsteady Pressure Measurements in a Heated Rotating Cavity 加热旋转腔内非定常压力测量

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59090

R. W. Jackson, Hui Tang, James A. Scobie, Oliver J Pountney, C. Sangan, J. Owen, G. Lock

{"title":"Unsteady Pressure Measurements in a Heated Rotating Cavity","authors":"R. W. Jackson, Hui Tang, James A. Scobie, Oliver J Pountney, C. Sangan, J. Owen, G. Lock","doi":"10.1115/gt2021-59090","DOIUrl":"https://doi.org/10.1115/gt2021-59090","url":null,"abstract":"\u0000 The flow in the heated rotating cavity of an aero-engine compressor is driven by buoyancy forces, which result in pairs of cyclonic and anticyclonic vortices. The resultant cavity flow field is three-dimensional, unsteady and unstable, which makes it challenging to model the flow and heat transfer. In this paper, properties of the vortex structures are determined from novel unsteady pressure measurements collected on the rotating disc surface over a range of engine-representative parameters. These measurements are the first of their kind with practical significance to the engine designer and for validation of computational fluid dynamics. One cyclonic/anticyclonic vortex pair was detected over the experimental range, despite the measurement of harmonic modes in the frequency spectra at low Rossby numbers. It is shown that these modes were caused by unequal size vortices, with the cyclonic vortex the larger of the pair. The structures slipped relative to the discs at a speed typically around 10% to 15% of that of the rotor, but the speed of precession was often unsteady. The coherency, strength and slip of the vortex pair increased with the buoyancy parameter, due to the stronger buoyancy forces, but they were largely independent of the rotational Reynolds number.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125106113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Impingement Heat Transfer Innovations and Enhancements: a Discussion on Selected Geometrical Features 碰撞传热的创新和改进:对选定几何特征的讨论

Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling Pub Date : 2021-06-07 DOI: 10.1115/gt2021-59394

S. Dutta, Prashant Singh

{"title":"Impingement Heat Transfer Innovations and Enhancements: a Discussion on Selected Geometrical Features","authors":"S. Dutta, Prashant Singh","doi":"10.1115/gt2021-59394","DOIUrl":"https://doi.org/10.1115/gt2021-59394","url":null,"abstract":"\u0000 Impingement heat transfer is considered as one of the most effective cooling technologies that yields in high localized convective heat transfer coefficient. This paper studies different configurational parameters involved in jet impingement cooling such as, exit orifice shape, crossflow regulation, target surface modification, spent air reuse, impingement channel modification, jet pulsation, and other techniques to understand what are critical and how these heat transfer enhancement concepts work. These enhancement factors have been explored in detail by many researchers, including standard parameters such as normalized distance between adjacent jets and jet-to-target spacing, and those known benefits are not repeated here. The aim of this paper is to stimulate the current scientific knowledge of this efficient cooling technique and instill some thoughts for future innovations. New orifice shapes are becoming feasible due to 3D printing technologies. However, the orifice studies show that it is hard to beat a sharp-edged round orifice. Any attempt to streamline the hole shape indicated a drop in the Nusselt number. Reduction in crossflow has been attempted with channel modifications. Use of high porosity conductive foam in the impingement space has shown marked improvement in heat transfer performance. A list of possible research topics based on this discussion are provided in conclusion.","PeriodicalId":385341,"journal":{"name":"Volume 5B: Heat Transfer — General Interest; Internal Air Systems; Internal Cooling","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129920894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1