Kenneth Mark Bryden

• PhD
• Professor at Iowa State University

This study examines the factors that affect fuelwood consumption in cookstoves and estimates fuelwood consumption associated with the use of cookstoves in a rural isolated West African village with a population of 770. Five primary applications of cookstoves were identified: cooking meals, heating water for washing, roasting peanuts, making medicin...

Over three billion people live in the rural areas of low- and middle-income countries. Often rural households have many unmet energy needs, including cooking, lighting, heating, transportation, and telecommunication. Designing solutions to meet these needs requires an understanding of the human, natural, and engineered systems that drive village en...

This study provides a spatially comprehensive assessment of sustainable agricultural residue removal potential across the United States for bioenergy production. Earlier assessments determining the quantity of agricultural residue that could be sustainably removed for bioenergy production at the regional and national scale faced a number of computa...

This study developed a computational strategy that utilizes data inputs from multiple spatial scales to investigate how variability within individual fields can impact sustainable residue removal for bioenergy production. Sustainable use of agricultural residues for bioenergy production requires consideration of the important role that residues pla...

Agricultural residues have near-term potential as a feedstock for bioenergy production, but their removal must be managed carefully to maintain soil health and productivity. Recent studies have shown that subfield scale variability in soil properties (e.g., slope, texture, and organic matter content) that affect grain yield significantly affect the...

This work presents a novel study for identifying alterations in the control states of a desuperheater system based on real closed-loop data from a coal-fired power plant operating under various loads using linear and nonlinear system identification techniques. Specifically, Transfer Functions (TFs) and Gaussian Processes within a Nonlinear AutoRegr...

A numerical study based on steady RANS with the SST turbulence model was performed to investigate the flow and heat transfer in a ribbed U-duct with a rectangular cross section that converges linearly in the radially outward direction and diverges linearly in the radially inward direction under rotating and non-rotating conditions. Parameters exami...

Blades in gas turbines have cross sections at the root that are larger than those at the tip so that internal cooling passages in blades are tapered. In this study, a reduced-order model (ROM) — based on the integral continuity, momentum, and energy equations for a thermally and calorically perfect gas was developed to enable rapid assessments of r...

A numerical study based on steady RANS with the SST turbulence model was performed to investigate the flow and heat transfer in a ribbed U-duct with a rectangular cross section that converges linearly in the radially outward direction and diverges linearly in the radially inward direction under rotating and nonrotating conditions. Parameters examin...

Scholars in economics, psychology, and business have recently defined narrative as the underlying mechanism by which humans internally process information and drive a decision forward. In this paper, we study narrative's use in design across Design Society publications. We discuss how narrative's role as the driver of design decision-making is an i...

Turbine inlet temperatures in advanced gas turbines could be as high as 2000 °C. To prevent ingress of this hot gas into the wheelspace between the stator and rotor disks, whose metals can only handle temperatures up to 850 °C, rim seals and sealing flows are used. This study examines the abilities of large eddy simulation (LES) based on the WALE s...

Engineering design research has largely focused on normative models of decision analysis based on small world causal frames where uncertainty can be resolved as probabilities or probability distributions. However, today we need to design solutions for our built environment that are sustainable, just, and able to adapt. Because of the scale and comp...

In gas turbines, the hot gas exiting the combustor can have temperatures as high as 2000 °C, and some of this hot gas enter into the space between the stator and rotor disks (wheelspace). Since the entering hot gas could damage the disks, its ingestion must be minimized. This is carried out by rim seals and by introducing a cooler flow from the com...

Large-eddy simulations (LES) were performed to study the turbulent flow in a channel of height H with a staggered array of pin fins with diameter D = H/2 as a function of heating loads that are relevant to the cooling of turbine blades and vanes. The following three heating loads were investigated—wall-to-coolant temperatures of Tw/Tc = 1.01, 2.0,...

This paper presents data from a preliminary study designed to test the hypothesis that narrative is the primary decisionmaking tool employed in engineering design. We also look for evidence that analysis and optimization provide anchor points that drive the narrative forward, even in the presence of unresolvable uncertainties. The data in this pape...

Gas turbine systems are widely used in the power industry because they provide continuous and reliable power to the electrical grid. One of the main concerns for implementing gas turbine systems is the maintenance costs. Therefore, predictive maintenance methods driven by Deep Learning (DL) models present an opportunity to extract important informa...

This work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural networ...

View Video Presentation: https://doi.org/10.2514/6.2022-1495.vid Today energy systems modeling and physical validation are largely separate activities connected by a human feedback loop. Computational modeling is flexible and very accurate for many aspects of energy system performance, but it cannot address all the issues. In the same way, physical...

This paper examines decision making under radical uncertainty in engineering design, that is, engineering decision making in those situations where it is not possible to know the outcomes and/or construct the utility functions and probabilities needed to support rational-human decision making. In these situations, despite being faced with radical u...

Real time models and digital twin environments represent a new frontier that allow the development of supplemental data analytics of measurable and unmeasurable parameters for a variety of power plant configurations. Performance prediction, monitoring of degradation effects, and a faster recognition of anomalous events during power plant load follo...

This chapter describes the market conditions and the role that energy storage can play in filling various market needs. This chapter also covers economic considerations and how to quantify the financial benefits. Then the chapter discusses technology considerations that effect the commercialization of an ESS. Finally, the chapter combines these top...

CFD simulation based on steady RANS were performed to assess the usefulness of adding a pair of “downstream” vortex generators (VGs) to improve the effectiveness of film cooling a flat plate through one row of inclined holes. Each VG in the pair is a rectangular plate with span S, chord C, and thickness t that is oriented at +45 or −45 degrees with...

For convective heat transfer involving multiple sources of different temperatures in the flow field such as in film cooling, the adiabatic-wall temperature, Tad, is used as the reference temperature to define the heat-transfer coefficient (HTC). Studies based on computational Fluid Dynamics (CFD) have always obtained Tad by requiring the cooled or...

With increasing regulation and the push for clean energy, the operation of power plants is becoming increasingly complex. This complexity combined with the need to optimize performance at base load and off-design condition means that predicting power plant performance with computational modeling is more important than ever. However, traditional mod...

Due to the increased penetration of renewable power sources into the electric grid, the current number of existing coal-fired power plants shifting from baseload to load-following operations has also increased. This shift creates challenges especially for the power industry as coal-fired power plants were not designed for ramping situations, leadin...

Proportional integral and derivative (PID) controllers are the most popular technique used in the power plant industry for process automation. However, the performance of these controllers may be affected due to variations in the power plant operating conditions, such as between startup, shutdown, and baseload/part-load operation. To maintain the d...

Clean energy has become an increasingly important consideration in today's power systems. As the push for clean energy continues, many coal-fired power plants are being decommissioned in favor of renewable power sources such as wind and solar. However, the intermittent nature of renewables means that dynamic load following with traditional power sy...

This paper presents a novel online system identification methodology that was implemented and validated for monitoring the performance of a micro gas turbine system designed for hybrid configuration at the National Energy Technology Laboratory (NETL). The main component of this methodology consists of an empirical transfer function model implemente...

Compressor dynamics were studied in a gas turbine - fuel cell hybrid power system having a larger compressor volume than traditionally found in gas turbine systems. This larger compressor volume adversely affects the surge margin of the gas turbine. Industrial acoustic sensors were placed near the compressor to identify when the equipment was getti...

Time-accurate 3-D CFD simulations based on the SST-SAS turbulence model were performed to study the effects of heat load on the unsteady flow and heat transfer in a cooling duct with a staggered array of short pin fins. For this duct, the static pressure at its exit is maintained at 25 bars, and the cooling air that enters has a temperature of 673...

Compressor dynamics were studied in a gas turbine – fuel cell hybrid power system having a larger compressor volume than traditionally found in gas turbine systems. This larger compressor volume adversely affects the surge margin of the gas turbine. Industrial acoustic sensors were placed near the compressor to identify when the equipment was getti...

A multiple model adaptive control (MMAC) methodology is used to control the critical parameters of a solid oxide fuel cell gas turbine (SOFC-GT) cyberphysical simulator, capable of characterizing 300 kW hybrid plants. The SOFC system is composed of a hardware balance of plant (BoP) component, and a high fidelity FC model implemented in software. Th...

A computational analysis was conducted to optimize the design of a solid oxide fuel cell - gas turbine hybrid power generator, focusing on the impact that fuel utilization within the fuel cell has on system efficiency and installed costs. This is the first ever design-study considering the effect of fuel utilization on performance, as well as on th...

The design of optimal control architectures and the optimal selection of controlled variables represents a critical task for maximizing the economic profitability of operating plants. Traditionally, controlled variables are selected based on heuristics or past experiences. For cyber-physical systems (CPS), where physical and virtual components can...

The emphasis on traditional control in power systems has traditionally focused on the application of first order transfer functions to develop gains in distributed PI or PID control. The application of traditional PI or PID control in fuel cell turbine hybrid power systems for setpoint tracking or disturbance rejection during transient operation ha...

Energy based Cyber-physical systems (CPS) find their greatest popularity in smart grid applications, where a complex computational algorithm imparts “intelligence” to a supervisory control and data acquisition (SCADA) system used for balancing load distributions. In contrast to this static application of CPS technology, research conducted jointly b...

This paper evaluates a state-space methodology of a multi-input multi-output (MIMO) control strategy using a 22 tightly coupled scenario applied to a physical gas turbine fuel cell hybrid power system. A centralized MIMO controller was preferred compared to a decentralized control approach because previous simulation studies showed that the couplin...

One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which mea...

In this paper we present a novel methodology for modeling engineered and other systems based on integrating a set of component models that are accessible as “model-as-a-service“ components within a cloud platform. These component models can be combined together to form a systems model. The component models are stateless and web-enabled. The advanta...

Optimal control structure design for cyber physical gas turbine fuel cell hybrid power plant. Use of multiagent metaheuristic optimization techniques for fast evaluation of alternatives that give compromise between economic objective function and controllability. Upon evaluation, a Pareto set of Controlled variables are chosen.

five minute presentation on the controlled variable selection for hybrid gas turbine fuel cell system

In this paper, biologically inspired adaptive control mechanisms are investigated for highly integrated, complex energy plants. The adaptive mechanisms are designed to augment the performance and robustness of baseline control laws under normal and abnormal operating conditions. Novel artificial neural network-based and artificial immune system-bas...

More than ever before, engineers are creating products for developing countries. One of the purposes of these products is to improve the consumer’s quality of life. Currently, there is no established method of measuring the social impact of these types of products. As a result, engineers have used their own metrics to assess their product’s impact,...

There are a variety of technologies that can help alleviate the energy poverty facing nearly 40% of the world’s population today. Yet the most effective among a variety of options is often not clear due to the range of outcomes desired by various stakeholders, constraints imposed by the local conditions and needs, and factors dictating the applicat...

A Multiple Model Adaptive Control (MMAC) methodology is used to control the critical parameters of a Solid Oxide Fuel Cell Gas Turbine (SOFC-GT) cyberphysical simulator, capable of characterizing 300kW hybrid plants. The SOFC system is comprised of a hardware Balance of Plant (BoP) component, and a high fidelity FC model implemented in software. Th...

Almost all measurements of the heat-transfer coefficient (HTC) or Nusselt number (Nu) in gas-turbine cooling passages with heat-transfer enhancement features such as pin fins and ribs have been made under conditions, where the wall-to-bulk temperature, Tw/Tb, is near unity. Since Tw/Tb in gas-turbine cooling passages can be as high as 2.2 and vary...

The use of cyber-physical systems to simulate novel hybrid power cycles provides a cost-effective means to develop and test control strategies at the pilot scale. One of the primary challenges of implementing a cyber-physical power system component is the seamless coupling of a real-time model with hardware that interacts with its environment. A re...

A cyber-physical fluidized bed-chemical looping reactor (FB-CLR) is proposed to observe and control the multiphase flow behavior and improve process operations, stability, and performance. The cyber-physical observer (CPO) provides an opportunity to probe a duplicate, or mirrored, non-reacting, multiphase flow system in real-time and provide respon...

This paper demonstrates a novel approach to solving inverse radiant enclosure problems based on distributed construction. Specifically, the problem of determining the temperature distribution needed on the heater surfaces to achieve a desired design surface temperature profile is recast as a distributed construction problem in which a shared resour...

This paper presents an attempt to address the challenge of modeling complex systems in which people, energy, and the environment meet. This challenge is met by developing a simple domain specific language for building systems models in a federated modeling environment. The language and its support infrastructure are designed for simplicity and ease...

We present a low-level model-to-model interface that will enable independent models to be linked into an integrated system of models. The interface is based on a standard set of functions that contain appropriate export and import schemas that enable models to be linked with no changes to the models themselves. These ideas are presented in the cont...

This paper develops a systems-based integrated model for investigating the impacts of various energy technologies as applied to meet specific energy needs in a rural developing village. The model enables the designer to examine of a variety of energy technology components subject to local and global constraints and reports the outcomes in terms of...

The heat transfer coefficient (HTC) is often averaged spatially when designing heat exchangers. Since the HTC could vary appreciably about a heat transfer enhancement feature such as a pin fin or a rib, it is of interest to understand the effects of averaging the HTC on design. This computational study examines those effects via a unit problem-a fl...

Engineering system modeling and design tools are needed to help successfully provide appropriate and desirable energy technologies to the 2.7 billion people presently relying on inefficient and polluting solid fuels to meet their basic energy needs for cooking, heating, and lighting. To understand the impacts of technology design choices and applic...

This paper presents an experimentally validated steady-state heat transfer model of a shielded-fire, natural-draft biomass cookstove suitable for conceptual design of the small household cookstoves used in developing countries. The input variables for the model included 10 geometrical design variables, 2 material design variables, and 3 operating c...

Increased energy demands are driving the development of new power generation technologies with high efficient. Direct fired fuel cell turbine hybrid systems are one such development, which have the potential to dramatically increase power generation efficiency, quickly respond to transient loads (and are generally flexible), and offer fast start up...

Ever increasing energy demands are driving the development of high-efficiency power generation technologies such as direct-fired fuel cell turbine hybrid systems. Due to lack of an accurate system model, high nonlinearities and high coupling between system parameters, traditional control strategies are often inadequate. To resolve this problem, lea...

When the operating condition of a gas turbine engine changes from one steady-state to another, the cooling must ensure that the solid's temperatures never exceed the maximum allowable throughout the transient process. Exceeding the maximum allowable temperature is possible even though cooling is increased to compensate for the increase in heating b...

Engineering design is a complex and iterative process that involves multiple engineering teams sharing and communicating information during the design process. One aspect of engineering design involves the development of physics-based models and their analysis via numerical simulations that are computationally expensive. To overcome the time constr...

Approximately 40% of the world’s population lives in energy poverty, lacking basic clean energy to prepare their food, heat water for washing, and provide light in their homes. Access to improved energy services can help to alleviate this poverty and result in significant improvements to health and livelihoods, yet past strategies for meeting the n...

This article reviews the cookstove modeling literature for one- to three-burner natural draft, wood-fired cookstoves fueled with solid unprocessed biomass ranging in size from 1 to 20 cm and operated by an individual in a residential setting. These household cookstove models are organized around the three major zones of the cookstove system: the fu...

This article presents a unified dataset of 63 points compiled from three published laboratory studies for the most common type of improved household cookstove used in the developing world—a cylindrical, natural draft, shielded, wood-fired cookstove. Each data point includes 11 geometric variables, thermal conductivity of the stove body and insulati...

The heat-transfer coefficient (HTC) in internal-coolant passages can vary appreciably about a heat-transfer enhancement feature such as a pin fin, a rib, and a concavity because of stagnation regions and wakes about the enhancement feature. However, the computed or measured HTC is often averaged spatially in the spanwise direction or over some regi...

Multi-coordination of actuators for a highly integrated, tightly coupled advanced power system was evaluated using the Hybrid Performance (Hyper) project facility at the U.S. Department of Energy’s National Energy Technology Laboratory (NETL). A two-by-two scenario in a fuel cell, turbine hybrid power system was utilized as a representative problem...

The lattice Boltzmann method (LBM) and traditional finite difference methods have separate strengths when solving the incompressible Navier–Stokes equations. The LBM is an explicit method with a highly local computational nature that uses floating-point operations that involve only local data and thereby enables easy cache optimization and parallel...

The burning of solid fuels for cooking creates significant adverse health, social, and economic consequences for more than three billion people worldwide. Recognizing this issue, many groups have worked to develop improved stoves that increase fuel efficiency, decrease fuel use, and reduce particulate emissions. Less attention has been given to dev...

The development of energy services for the 40% of the world's population currently living in energy poverty is a challenging design problem. There are competing and often conflicting objectives between stakeholders from global to user viewpoints, and the confounding effects of real-world performance, rebound, and stacking of technologies makes the...

The lattice Boltzmann method is being increasingly employed in the field of computational fluid dynamics due to its computational efficiency. Floating-point operations in the lattice Boltzmann method involve local data and therefore allow easy cache optimization and parallelization. Due to this, the cache-optimized lattice Boltzmann method has supe...

As the scale and complexity of engineered systems grows, the effectiveness of traditional engineering tools shrinks. In the new world of complex multiscale systems, integrated computational design environments will be essential tools for engineers to understand and make decisions about the systems they are designing and optimizing. New tools are ne...

Digital manufacturing significantly reduces the expense and time required to produce custom products. Utilizing this technology, a customized product can be quickly manufactured. But the timescale and expense of the engineering design workflows used to develop these customized products have not been adapted from the workflows used in mass productio...

Computational fluid dynamics is not often used early in the conceptual design stage of product development due to the lengthy computation times involved with solving complex computational fluid dynamics models. At this early stage, design options are being explored and significant changes are common, and therefore updated solutions must be found qu...

Often the emergent behavior of large-scale complex engineered and natural systems is a consequence of the interaction and interconnectivity between a large numbers of component subsystems. Consequently, modeling and simulating these large-scale systems requires methods that enable large numbers of heterogeneous, distributed models and databases to...