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Continuum-scale modeling of water infiltration into a stack of two thin fibrous layers and their inter-layer space
Unsaturated water flow through thin porous layers plays an important role in many applications such as water management in hydrogen fuel cells and hygiene products. It is well known that void spaces between adjacent thin layers (i.e., layer-layer interfaces) considerably impact through-plane water infiltration. Therefore, it is essential to account for this fact in the …
Fast and robust quantification of liquid inside thin fibrous porous materials with single-sided NMR
Single-sided NMR with the NMR-MOUSE is employed for the characterization of fluids in fibrous and open foam materials. One of the key aspects of this study is the quantification of the fluid amount. To this end critical information was provided by a relaxation study. Using 2 mM/L of a Gd3+ relaxation agent the repetition time could be shortened to …
Continuum-Scale Modeling of Liquid Redistribution in a Stack of Thin Hydrophilic Fibrous Layers
Macroscale three-dimensional modeling of fluid flow in a thin porous layer under unsaturated conditions is a challenging task. One major issue is that such layers do not satisfy the representative elementary volume length-scale requirement. Recently, a new approach, called reduced continua model (RCM), has been developed to describe multiphase fluid flow in a stack of …
Revealing how interfaces in stacked thin fibrous layers affect liquid ingress and transport properties by single-sided NMR
Offering multifaceted applications, thin fibrous porous materials are mostly used in stacks of layers, each layer having a defined functionality. Since only a few pores exist across a layer a couple of hundred microns thick, the interface between layers may significantly affect liquid ingress. Thus, the main objective of the study is to substantiate that …
One and two-dimensional NMR to evaluate the performance of consolidants in porous media with a wide range of pore sizes: Applications to cultural heritage
The conservation of historical buildings and outdoor cultural assets is of great value for the humankind. In this context, consolidation treatments represent a fundamental procedure to assure the survival of deteriorated cultural artefacts. For porous materials characterized by a wide distribution of pore sizes, adequate consolidation treatments require a product with a sufficient penetration depth and homogeneous …
Small-scale instrumentation for nuclear magnetic resonance of porous media
The investigation of fluids confined to porous media is the oldest topic of investigation with small-scale nuclear magnetic resonance (NMR) instruments, as such instruments are mobile and can be moved to the site of the object, such as the borehole of an oil well. While the analysis was originally restricted by the inferior homogeneity of …
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Permeability Prediction for Low Porosity Rocks by Mobile NMR
Estimating permeability from NMR well logs or mobile NMR core scanner data is an attractive method as the measurements can be performed directly in the formation or on fresh cores right after drilling. Furthermore, the method is fast and non-destructive. Compared to T1 relaxation times, commonly measured T2 distributions are influenced by external and internal magnetic field gradients. We …
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Porosity and Permeability from Mobile NMR Core-Scanning
Two types of mobile Nuclear Magnetic Resonance (NMR) core-scanners were used to measure porosity and estimate the pore-size distribution of water-saturated drill cores. Both devices are experimental prototypes and differ in their magnetic field strength and homogeneity. Whereas the magnetic field of the unilateral NMR-MOUSE® is applied to the sample from one side and is …
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Mobile NMR Device for Measurements of Porosity and Pore Size Distributions of Drilled Core Samples
A new mobile NMR scanner has been designed with a Halbach magnet for measurements of porosity and pore‐size distributions of water‐saturated cylindrical geological cores with diameters up to 60 mm. It is light (∼8 kg) and has a sufficiently homogeneous magnetic field in a large and accessible cylindrical volume. Practical aspects of the sensor construction …