Developing the Small Particle Heat Exchange Receiver for a Prototype Test · PROTOTYPE TEST...

SDSU Combustion and Solar Energy Laboratory 1

DEVELOPING THE SMALL PARTICLE HEAT EXCHANGE RECEIVER FOR A

PROTOTYPE TEST

Fletcher Miller, Principal Investigator Department of Mechanical Engineering,

San Diego State University

SunShot

Concentrating Solar Power Program Review 2013

Phoenix, AZ

Tuesday, April 23rd, 2013

1


Project Partners

Start Date: Sept. 1st, 2012

Michael McDowell Rocketdyne

Arlon Hunt Thermaphase

David Teraji Solar Turbines Andrew Clarkson

L-3 Brashear


Presentation Outline

• Concept of the Small Particle Solar Receiver • Project Objectives and Description • Lab-Scale Component Testing • Receiver window design (optical/mechanical) • Radiation heat transfer and thermo/fluid

dynamic modeling • Challenges & Future work


Solar Central Receivers

Solar One, Barstow, California Our proposed technology, a gas-small particle receiver, can efficiently deliver the temperatures needed for a high-efficiency, gas turbine (Brayton cycle).

“New” Receiver Concept

Commercial central receivers use either molten salt or steam as the coolant, and are limited to medium temperatures and moderate solar fluxes


Small Particle Receiver Under Renewed Development at SDSU

Advantages:

• Radiation is absorbed by sub-micron carbon particles, which act as selective, efficient absorbers of solar radiation.

• Extremely high temperatures and flux levels are possible, because the absorbers are expendable.

• The carbon particles oxidize once they reach high temperatures.

• The small particles are at thermal equilibrium with their surroundings (no resistance to heat transfer).

• Pressure drops are minimized by removing tubes or foam absorbers.

Schematic of a Small Particle Receiver Conceptual Small Particle Receiver


Comp

Receiver

Recp

B

1

2

3 4

7

Solar receiver goes in-line with the combustor.

Advantages for Gas Turbines: – High efficiency – Low water

consumption – Possible combined

cycle – Ease of Operation

Small Particle Receiver in a Gas Turbine Cycle

Recuperated Gas Turbine Cycle


Project Objectives

• The objective of this project is to design, construct, and test a revolutionary high temperature small particle solar receiver in the multi-MW range that can be used to drive a gas turbine to generate low-cost electricity.

• A secondary objective is demonstrating for the first time a pressurized solar receiver with a window greater than 1 m in diameter.


• Phase 1 – Lab-Scale Component Testing – Window and Seal Design – Full-scale Particle Generator Design – Receiver Modeling and Preliminary Design

• Phase 2 – Finalize Designs, Fabricate and Test Components

• Phase 3 – Assemble components and test receiver at the National Solar Thermal Test Facility at Sandia National Labs.

Project Description


Lab-Scale System


Single Particle Absorption Efficiency vs. Wavelength


Scanning Electron Micrograph (SEM) of Particles on a Filter

5 µm

Use two techniques to measure the size: • Angular Light

Scattering

• Count particles on the filter using ImageJ


Comparing DPS data to SEMs (DPS = Diesel Particle Scatterometer using angular light scattering)

• DPS data matches SEM analysis to within a few nanometers.

Nitrogen Flow Rate = 600 SCCM Temperature = 1000 degrees C

Natural Gas Flow Rate (SCCM) SEM Size (nm) DPS Size (nm) Difference (nm)

20 178 181 3

20 177 175 2

40 275 250 15

SDSU Combustion and Solar Energy Laboratory 13 13

Window and Mount Design


Window Optical Analysis

• Start with optical constants (n and k) of quartz. • Use Generalized Fresnel Equations to determine

transmission, reflection, and absorption • MIRVAL calculates incident radiation from

heliostat field (modified for spectral calculations) • In-house code traces rays interacting with the

window and entering receiver.


Window Solar Absorption Maps


84

86

88

90

92

94

96

0 10 20 30 40 50 60 70 80 90

Tra

nsm

issi

on %

Cap Angle

Transmission for Ellipsoidal Window (HSQ 300) Transmission for Ellipsoidal Window (HOQ 310)

Transmission Transmission for Ellipsoidal Window

Transmission (HSQ 300) Transmission HOQ 310

Window Transmission vs. Cap Angle


Weibull Failure Probability

Stress Intensity Factor (Ki)

Apply Dynamic Fatigue

Determine Design Strength

Trade Study of Window Mount

FEA Structural Thermal

Implement

Verify Thru Small Scale Test

Detailed Design (Drawings, Assy Procedures, Etc.)

Window Mechanical Design Process R

elia

bilit

y Eng. D

esign


Hemispherical Cap window and Mount


Failure Probability • Based on Weibull Probabilistic Failure (Static Strength), characteristic

strength = 38MPa, m=10 • At .01% take FS of 2, arrive at 𝝈acceptable~7.5MPa

0.10%

0.01% 19

𝑃𝑓 = 1.0 − 𝑒 − 𝜎𝜎𝑜

𝑚


Principle Stresses in Spherical Cap

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

0 10 20 30 40 50 60 70St

ress

es,M

pa

Φ

Bending Stresses in a Sphere with Fixed Edges P=5Bar,

φ=60o, aperture=1.5m

Sigma 1

Sigma 2

Sigma 3

20


Receiver Fluid Dynamic and

Radiation Modeling

SDSU Combustion and Solar Energy Laboratory

Schematic of 2-D Receiver Model

22

Concentrated Solar

Radiation

Air-Particle Inlet

Air-Particle Inlet

Flow Direction

Hot Air Outlet

0.6m


Model Program Overview

23

Temperature (r,z) FLUENT -Energy -Momentum -Mass

MCRT (FORTRAN)

-Radiation

• MCRT solves radiative transfer equation

• Fluent solves energy, momentum, & mass equations

• Temperature data is passed to FORTRAN code

• Volumetric source terms (−𝛻 ∙ 𝑞𝑟) are passed to FLUENT

• Process iterates until convergence

Source Terms (r, z) (−𝛻 ∙ 𝑞𝑟)


Results - Mass-Flow Rate Variation • 4kg/s • 5 MW • 1547 K outlet • 86.3% receiver

efficiency

24

• 6kg/s • 5 MW • 1325 K outlet • 90.4% receiver

efficiency


Results - Mass-Flow Rate Variation

• Input power is Gaussian-distributed 5 MW for all five cases

25

80%

81%

82%

83%

84%

85%

86%

87%

88%

89%

90%

91%

1300

1350

1400

1450

1500

1550

1600

3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0

Rec

eive

r E

ffic

ienc

y

Out

let T

empe

ratu

re [K

]

Gas Mass Flow Rate [kg/s]

Gas Outlet Temperature vs. Mass Flow Rate

TemperatureEfficiency


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Capabilities of the newest Software

• Three-Dimensional Model.

• Arbitrary axisymmetric geometries.

• Solar irradiation from heliostat field • Window included in the MCRT model.

Presenter

Presentation Notes

The outlet tube is already present in the last version of the 2-D model.


3-D Model Results

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SIMULATION CONDITIONS: Time: 12pm on March 21st Mass flow: 4kg/s RESULTS: Outlet temperature: 1450 K Efficiency: 90% Pressure drop: 91 Pa Maximum wall temperature: 1450 K

Temperature field (K)


Challenges to Date • Particle Generator does not work well at higher pressures.

– Undergoing redesign with Senior Project Team

• Exact optical constants of glass not available at all wavelengths.

– Did bracketing calculations. Evaluating measurement of constants.

• 3-D calculations take a long time (days)

– Considering GPU, supercomputer, and cluster options.

• Staffing may not match tasks exactly

– Working to strengths available


Future Work in Phase 1

• Use three-dimensional coupled model to perform preliminary receiver design

• Complete window thermal and mechanical design (includes seal)

• Redesign particle generator and perform component lab-scale testing at 5 atm.

• Design full-scale particle generator.


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Acknowledgements Google Re<C Program California Energy Commission DOE Sunshot Program Award # DE-EE0005800 Students in the SDSU Combustion and Solar Energy Laboratory: Adam Crocker Pablo Fernandez del Campo Lee Frederickson Milorad Dordevich Ahmet Murat Mecit Trent Martin E-Fann Saung Kyle Kitzmiller Alex Whitmore Ara Hovhannisian


Thank you for your Attention!

Developing the Small Particle Heat Exchange Receiver for a Prototype Test · PROTOTYPE TEST...

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