Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “tube bundle”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

17 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Enhanced pool boiling heat transfer with metal foam tubes in inline tube bundle configuration

Flooded evaporators, commonly known as shell-and-tube heat exchangers, are widely used in large-scale industrial refrigeration and air-conditioning systems due to their high pool boiling heat transfer efficiency. However, their bulky configuration requires a large refrigerant inventory, which poses safety challenges—particularly when employing next-generation A2L refrigerants that are mildly flammable. Here, to address this issue, the development of compact heat exchangers with enhanced heat transfer performance is essential. In this study, a novel metal foam tube design is proposed to augment pool boiling heat transfer. Experiments were conducted at a saturation temperature of 20 °C and across a heat flux range of 7–60 kW m −2 . The tests were conducted for both smooth and metal foam tubes with an inline tube bundle configuration and for a pitch–to–diameter (P/D) ratios of 1.3 and 1.5. Pool boiling performance was evaluated for next-generation hydrofluoroolefin (HFO) refrigerants, R1234yf and R1234ze(E), with R134a serving as the baseline fluid. The results indicate that the heat transfer coefficient (HTC) of R1234yf is comparable to R134a, while R1234ze(E) shows slightly lower performance. Importantly, the metal foam tubes achieved up to a 217% enhancement in HTC compared to smooth tubes.

Metal foam tubes↗
NASA NTRS1983

Reynolds number effects on pressure loss and turbulence characteristics of four tube-bundle heat exchangers

The aerodynamic characteristics of pressure loss and turbulence on four tube-bundle configurations representing heat-exchanger geometries with nominally the same heat capacity were measured as a function of Reynolds numbers from about 4000 to 400,000 based on tube hydraulic diameter. Two configurations had elliptical tubes, the other two had round tubes, and all four had plate fins. The elliptical-tube configurations had lower pressure loss and turbulence characteristics than the round-tube configurations over the entire Reynolds number range.

Gentry, L., Jr.↗
DOE OSTI2024

Novel Full-Ceramic Multi-Tubular Membrane Systems for Pre-Combustion CO2 Capture with Simultaneous H2 Production: Fabrication, Performance Testing, and 3D CFD Modeling

Inorganic membranes show promise for application in pre-combustion CO2 capture with simultaneous H2 production. State-of-the-art systems for use under high temperature and pressure conditions consist of multiple membrane tube bundles prepared in a "candle-filter" configuration, in which the membrane tubes are open at one end and sealed at the other. This configuration is used for practical reasons, specifically the need to minimize potential problems due to thermal expansion mismatch, at high temperatures, between the ceramic tube bundle and the steel housing. The primary technical problem with the candle-filter configuration for use in commercial-scale installations is the inability to purge the permeate side (typically the tube side), a feature that is crucial for high H2 recovery. In this study, we fabricated dual-end open, commercial-size ceramic multiple-tube bundles made of zeolite, palladium (Pd), and carbon molecular sieve (CMS) membranes that enable permeate-side (tube-side) purge for gas separation applications. Experimental gas separation data with these membrane bundles under harsh operating conditions (temperatures up to 350 and pressures up to 800 psig), to be presented at the meeting, manifest excellent performance. Parallel to the membrane bundle construction and testing efforts, we have also developed a detailed 3D CFD modeling package using COMSOL Multiphysics software to gain more insight into the effect on the H2 purity and recovery of the detailed geometry of the multi-tubular membrane system, including the number of tubes used, their dimensions, and placement in the bundle, as well as the number, type, and positioning of internal baffles and other flow-enhancement accessories. The CFD package is validated with experimental data from different systems (1-tube, 3-tube, and 19-tube bundles), and shows high accuracy in predicting the experimental results (<5 % error in all cases). The results of our study show that the detailed internal geometry of these multi-tubular membrane systems has a considerable impact on the performance of the system as the flow maldistribution within the shell-side can substantially decrease (>40%) the H2 recovery.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1979

Aerodynamic characteristics at low Reynolds numbers of several heat-exchanger configurations for wind-tunnel use

In response to design requirements of the National Transonic Facility, aerodynamic tests were conducted to determine the pressure-drop, flow-uniformity, and turbulence characteristics of various heat-exchanger configurations as a function of Reynolds number. Data were obtained in air with an indraft flow apparatus operated at ambient temperature and pressure. The unit Reynolds number of the tests varied from about 0.06 x 10 to 6th power to about 1.3 x 10 to 6th power per meter. The test models were designed to represent segments of full-scale tube bundles and included bundles of round tubes with plate fins in both staggered and inline tube arrays, round tubes with spiral fins, elliptical tubes with plate fins, and an inline grouping of tubes with segmented fins.

Johnson, W. G., Jr.↗
NASA NTRS1977

Tubular sublimatory evaporator heat sink

An evaporative refrigerator or cooler comprising a bundle of spaced, porous walled tubes closed at one of their ends and vented to a vacuum at the other end is disclosed. The tube bundle is surrounded by a water jacket having a hot water inlet distribution manifold and a cooled water outlet through a plenum chamber. Hot water is pumped into the jacket to circulate around the tubes, and when this water meets the vacuum existing inside the tubes, it evaporates thereby cooling the water in the jacket. If cooling proceeds to the point where water penetrating or surrounding all or part of the tubes freezes, operation continues with local sublimation of the ice on the tubes while the circulating water attempts to melt the ice. Both sublimation and evaporation may take place simultaneously in different regions of the device.

Webbon, B. W.↗
DOE OSTI2025

Compact Counter Flow Fluidized Bed Heat Exchanger (Final Report)

Generation 3 concentrating solar power systems which utilize solid granular media as the heat transfer and storage media hold promise in reducing the levelized cost of electricity relative to generation 2 systems which utilize molten salt. The particles can be heated to temperatures exceeding 800 °C which enables the use of high efficiency supercritical CO 2 Brayton power cycles. A key challenge associate with the use of solid media is its low bulk thermal conductivity which limits the ability to transfer heat from the particles to a working fluid, such as supercritical CO 2 . Tradition shell and tube and shell and plate heat exchangers feature gravity driven particle flow which limits the maximum particle side heat transfer coefficient in these systems to approximately 400 W/m 2 K. A fluidized bed heat exchanger does not rely solely on gravity for particle flow. Instead, enhanced mixing and horizontal conveyance is achieved through fluidization induced through air injection at the bottom of a bed of particles. A tube bundle within the bed conveys the supercritical CO 2 which is heated via the turbulent particle motion at the tube wall.

14 SOLAR ENERGY↗
NASA NTRS1977

Large-scale thermal energy storage using sodium hydroxide /NaOH/

A technique employing NaOH phase change material for large-scale thermal energy storage to 900 F (482 C) is described; the concept consists of 12-foot diameter by 60-foot long cylindrical steel shell with closely spaced internal tubes similar to a shell and tube heat exchanger. The NaOH heat storage medium fills the space between the tubes and outer shell. To charge the system, superheated steam flowing through the tubes melts and raises the temperature of NaOH; for discharge, pressurized water flows through the same tube bundle. A technique for system design and cost estimation is shown. General technical and economic properties of the storage unit integrated into a solar power plant are discussed.

Turner, R. H.↗
NASA NTRS1979

Lean stability augmentation for premixing, prevaporizing combustors

An experimental program was conducted to investigate techniques for improving the lean combustion limits of premixing, prevaporizing combustors applicable to gas turbine engine main burners. Augmented flameholders employing recessed perforated plates, catalyzed tube bundles, and configurations in which pilot fuel was injected into the wakes of V-gutters or perforated plates were designed and tested. Stable operation of the piloted designs was achieved at equivalence ratios as low as 0.25; NOx emissions of less than 1.0 g/kg at simulated turbine engine cruise conditions were obtained. A piloted perforated plate employing four percent pilot fuel flow produced the best performance while meeting severe NOx constraints.

Mcvey, J. B.↗
NASA NTRS1981

Space Shuttle main engine nozzle-steerhorn dynamics

On two occasions during the Space Shuttle main engine development, the LH2 feedline (called the steerhorn, because of its shape) failed during the cutoff transient. A dynamic test was undertaken, and an analytical model was developed and correlated to the dynamic test. Detailed models of the tube bundle were required to obtain the equivalent shell coefficients. All-shell models of the nozzle wall were found better than beam-shell models. The most difficult part of the structure to simulate was the felt-metal pad between the feedline and its mount, which introduced nonlinear stiffness and damping and led to the use of separate low amplitude and high amplitude models. The total structure was found to have 400 modes in the frequency range of interest, 0 to 500 Hz. Good test analysis correlation was obtained and a modified feedline configuration was found to demonstrate a 40% reduction of response stress from the original configuration.

Kiefling, L.↗
DOE OSTI2025

Extended Heat Transfer Model Dataset

Data repository for the paper: Molerus and Wirth's Heat Transfer Model for Bubbling Fluidized Beds: Proposal for an Extended Model Including Immersed Tube Banks and Particle Cross-Flow Powder Technology 2025

contact time↗
NASA NTRS1976

Method and apparatus for fluffing, separating, and cleaning fibers

A perforated tube is housed in a chamber in which vacuum is drawn. An air jet is directed into one end of the tube and fiber bundles are fed into the jet which separates and dispenses individual fibers from the bundle, fluffs them, cleanses them of any particulate material, and carries them into the tube. The tube retains the fibers while fiber fragments, undesirably short fibers and particulate matter are drawn by the vacuum and resultant air flow out of the tube through its perforations to a suitable discharge.

Padilla, D.↗
NASA NTRS1983

Cathode degradation and erosion in high pressure arc discharges

The various processes which control cathode erosion and degradation were identified and evaluated. A direct current arc discharge was established between electrodes in a pressure-controlled gas flow environment. The cathode holder was designed for easy testing of various cathode materials. The anode was a water cooled copper collector electrode. The arc was powered by a dc power supply with current and voltage regulated cross-over control. Nitrogen and argon were used as propellants and the materials used were two percent thoriated tungsten, barium oxide impregnated porous tungsten, pure tungsten and lanthanum hexaboride. The configurations used were cylindrical solid rods, wire bundles supported by hollow molybdenum tubes, cylindrical hollow tubes, and hollow cathodes of the type used in ion thrusters. The results of the mass loss tests in nitrogen indicated that pure tungsten eroded at a rate more than 10 times faster than the rates of the impregnated tungsten materials. It was found that oxygen impurities of less than 0.5 percent in the nitrogen increased the mass loss rate by a factor of 4 over high purity nitrogen. At power levels less than 1 kW, cathode size and current level did not significantly affect the mass loss rate. The hollow cathode was found to be operable in argon and in nitrogen only at pressures below 400 and 200 torr, respectively.

Hardy, T. L.↗
NASA NTRS1973

Electron-optic limitations on image resolution

Various approaches are considered to the solution of the electron-optical problem of designing an image tube configuration. Emphasis is placed on the method of computer design, and an illustration is given in which the technique is used in the design of an 80-mm image tube with a zoom capability of 3:1. The solutions are discussed to such problems as image distortion, magnification, and electron bundles striking the zoom electrode. Three types of an electron-optical configuration are examined for the electron-optic limitations to resolution: (1) the proximity image tube, (2) the magnetic-type image tube having uniform electric and magnetic fields, and (3) the electrostatic-type image tube such as the 80-mm zoom tube.

Engstrom, R. W.↗
NASA NTRS1982

Optical tip clearance sensor for aircraft engine controls

Aircraft gas turbine performance and efficiency are related to airfoil tip clearance. The possibility has been considered to obtain optimum performance and efficiency by reducing clearance to a safe minimum with the aid of a closed-loop tip clearance control system, which utilizes a tip clearance sensor. The use of optical sensing methods appears to represent a potential solution to the tip clearance measurement problem. Principles of sensor operation are discussed along with dimensional considerations and diffraction limitations. A description is presented of the study of the feasibility of a certain sensor, taking into account the test rig system, the optical components, and the mounting tube. Attention is also given to the operation of the feasibility-study sensor, performance estimations, the optical fiber bundle, light beam refraction, and aspects of aircraft engine implementation.

Poppel, G. L.↗
DOE OSTI2025

Simulations of muon imaging with the LANL GMT detector for spent nuclear fuel cask content verification

Atmospheric muons are typically high energy, highly penetrating charged particles. They interact with matter primarily through multiple Coulomb scatterings. Muon scattering intensities can be used to characterize the density and atomic number of the matter that they pass through. Previously, the Los Alamos National Laboratory (LANL) muon tomography team performed muon imaging of the partially filled MC-10 spent nuclear fuel (SNF) cask at Idaho National Laboratory (INL). This experiment demonstrated the feasibility of muon imaging for the verification of spent fuel container contents. That original effort used the mini muon tracker array, consisting of two arrays of drift tubes on either side of the SNF cask. The reconstructed image quality was limited by statistics, largely due to low muon flux at high zenith angles. A LANL led team will perform new measurements with a larger array, the Giant Muon Tracker (GMT), to improve data collection rates and statistics. In this work, simulations were performed with the GMT near the partially filled INL MC-10 cask. For more general fuel diversion detection, a full MC-10 cask and casks with a singular missing fuel bundle were also simulated. To understand minimum measurement times needed for missing bundle identification, 100 000 to millions of tracked muons (corresponding to 1.4 days to several weeks measurement time) were analyzed. Simulated images were then analyzed visually and numerically to explore techniques designed to minimize the collection time needed to identify the diversion of fuel in each scenario.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗