Simulation of two-phase liquid cooling for thermal prediction of direct liquid cooling schemes

• US 5,050,114 A
• Filed: 09/17/1990
• Issued: 09/17/1991
• Est. Priority Date: 09/17/1990
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lee, Tien-Yu T.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US07/583,759
• Time in Patent Office: 365 Days
• Field of Search: 364/551.01, 364/578, 361/385, 357/82, 357/81, 357/83
• US Class Current: 703/9
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method for predicting the optimum operating conditions for a two-phase liquid cooling environment using simulation software utilizes a data base containing properties for several liquid coolants. A coolant is selected from the data base, and a cooling scheme is designated. Physical properties related to an integrated circuit are entered, includinhg circuit surface heat flux. A coolant temperature and flow rate are selected. The operating conditions for the integrated circuit are calculated based upon the cooling scheme and test conditions, including calculating boiling incipience heat flux and critical heat flux. The circuit surface heat flux is compared to the boiling incipience heat flux and critical heat flux to determine if the test conditions provide for nucleate boiling. The calculations are repeated for additional temperatures and flow rates. Results are displayed in printed or graphic form.

Claims

1. A method for predicting optimal operating conditions for two-phase liquid cooling of integrated circuits, comprising;

providing a data base which contains physical and thermodynamic properties for a plurality of liquid coolants used in a plurality of cooling schemes;

selecting one of the plurality of liquid coolants and one of the plurality of cooling schemes from the data base;

entering physical properties related to an integrated circuit, at least comprising entering integrated circuit surface heat flux;

selecting a temperature and a flow rate as a set of test conditions for the selected liquid coolant from a range of temperatures and flow rates;

calculating operating conditions for the integrated circuit based upon the selected cooling scheme and test conditions, at least comprising calculating boiling incipience heat flux and critical heat flux;

comparing the heat flux of the integrated circuit to the calculated boiling incipience heat flux and critical heat flux to determine if the test conditions provide for nucleate boiling;

repeating the method, beginning with selecting a temperature and a flow rate, until the entire range of temperatures and flow rates has been selected;

displaying results in printed or graphic form; and

using the results displayed to choose an appropriate flow rate for the selected liquid coolant.

2. The method of claim 1 wherein providing a data base comprises:

providing tables for densities of saturated liquid, densities of saturated vapor, and enthalpies of evaporation based upon system pressure;

providing average molecular weights;

providing equations of state;

providing equations for calculating boiling temperatures, surface tensions, kinematic viscosities, specific heats, thermal conductivities, volumetric coefficients of thermal expansion; and

providing heat transfer characteristics for the plurality of liquid coolants.

3. The method of claim 1 wherein entering physical properties additionally comprises entering a packaging model, integrated circuit heating length, and system pressure.

4. The method of claim 1 wherein calculating operating conditions additionally comprises calculating a single phase heat transfer coefficient, integrated circuit temperature at boiling incipience, integrated circuit temperature at nucleate boiling, density of saturated liquid and a density of saturated vapor, enthalpy of evaporation, surface tension, kinematic viscosity, specific heat, thermal conductivity, and thermal expansion coefficient.

5. A method for determining operating parameters required to sustain nucleate boiling activity in a two-phase liquid cooling scheme used to cool an integrated circuit having a high surface heat flux, comprising:

calculating boiling incipience heat flux and critical heat flux for the cooling scheme based upon predetermined test conditions;

comparing the boiling incipience heat flux and the critical heat flux to the surface heat flux of the integrated circuit to determine whether the specified test conditions provide for nucleate boiling; and

selecting an appropriate flow rate for a two-phase liquid coolant chosen for the cooling scheme.

6. The method of claim 5 wherein the specified test conditions are determined to provide for nucleate boiling if the surface heat flux of the integrated circuit is greater than the boiling incipience heat flux and less than the critical heat flux.